Testing And Adjusting

Usage:

Introduction

NOTE: For Specifications with illustrations, make reference to Specifications for 3500 Spark Ignited Engine Attachments, Form No. SENR4603. If the Specifications in Form SENR4603 are not the same as in the Systems Operation and the Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.

Troubleshooting

Troubleshooting can be difficult. On the following pages there is a list of possible problems. To make a repair to a problem, make reference to the cause and correction.

This list of problems, causes, and corrections will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more or other repair work is needed beyond the recommendations in the list. Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list cannot give all possible problems and corrections. The service personnel must find the problem and its source, then make the necessary repairs.

Troubleshooting Problem List

1. Engine Will Not Turn When Start Switch Is On.

2. Engine Will Not Start/Engine Starts, But Shuts Down.

3. Misfiring Or Running Rough.

4. Stall At Low RPM.

5. Sudden Changes In Engine Speed (RPM).

6. Not Enough Power.

7. Too Much Vibration.

8. Loud Combustion Noise.

9. Loud Noise (Clicking) From Valve Compartment.

10. Oil In Cooling System.

11. Mechanical Noise (Knock) In Engine.

12. Gas Consumption Too High.

13. Loud Noise From Valves Or Valve Drive Components.

14. Little Movement Of Rocker Arm And Too Much Valve Clearance.

15. Valve Rotocoil Or Spring Lock Is Free.

16. Oil At The Exhaust.

17. Little Or No Valve Clearance.

18. Engine Has Early Wear.

19. Coolant In Lubrication Oil.

20. Exhaust Temperature Is Too High.

21. Engine Has Low Oil Pressure.

22. Engine Uses Too Much Lubrication Oil.

23. Engine Coolant Temperature Is Too High.

24. Electric Starter Motor Does Not Turn.

25. Alternator Gives No Charge.

26. Alternator Charge Rate Is Low Or Not Regular.

27. Alternator Charge Too High.

28. Alternator Has Noise.

29. Short Spark Plug Life.

30. Detonation.

31. Gas Supply Line Shutoff Valve Failure.

32. Air Starting Motor Turns Slowly Or Has A Loss Of Power.

33. Air Starting Motor Pinion Does Not Engage With The Flywheel.

34. Air Starting Motor Runs, Pinion Engages But Does Not Turn Flywheel.

35. Air Starting Motor Pinion Does Not Engage Correctly With The Flywheel.

36. Solid State Magneto (Altronic).

37. Electric Protective Systems. See:

Form No. SENR4616, Electric Protective System Energize To Run (SI-ETR)

Form No. SENR4617, Troubleshooting Guide Electric Protective System Energize To Run (SI-ETR)

Form No. SENR4618, Control Panel (Status-Timing) For 3500 Spark Ignited Engines

Problem 1: Engine Crankshaft Will Not Turn When Start Switch Is On

Probable Cause:

1. Problem With Air Starter Motor

Make reference to Problem 32.

2. Problem With Electric Starter Motor

Make reference to Problem 24.

3. Oil Pressure Switch For Prelubrication Pump Has A Defect

Make a replacement of defective switch.

4. Prelubrication Oil Pump Has A Defect

Repair or replace pump components as needed.

5. Status Control Has Detected A Fault Or Has A Defect

Refer to the Troubleshooting Section of Form No. SENR4618, Control Panel (Status-Timing) For 3500 Spark Ignited Engines.

6. Timing Control Has Detected A Fault

Refer to 3500 Spark Ignited Electronic Troubleshooting, Form No. SENR4612.

7. Inside Problem Prevents Engine Crankshaft From Turning:

If the crankshaft cannot be turned after disconnecting the driven equipment, remove the spark plugs and check for fluid in the cylinders. If fluid in the cylinders is not the problem, the engine must be disassembled to check for other inside problems. Some of these inside problems are bearing seizure, piston seizure, wrong pistons installed in the engine, and valves making contact with pistons.

Problem 2: Engine Will Not Start Or Engine Starts, But Shuts Down

Probable Cause:

1. No Gas To Engine

Check gas supply and pressure regulator. Reset shutoff valve in the supply line. Check carburetor throttle, and linkage between carburetor and governor.

2. Wrong Ignition Timing

Set magneto timing (see Magneto Timing).

3. Timing Control Has A Defect Or Detected A Fault

Refer to 3500 Spark Ignited Electronic Troubleshooting, Form No. SENR4612.

4. Ignition System Failure

Check the ignition transformers for loose connection, moisture, short or open circuits. Check the primary and secondary wiring. Check the spark plugs for correct type. Check the magneto. Repair or replace any component that shows signs of failure. Make reference to Problem 36.

5. Gas Line Pressure Regulator Not Working

Clean balance line. Check inlet and outlet regulator pressures. Disassemble and inspect.

6. Carburetor Not Working

Check all carburetor adjustments. Be sure that throttle plate is open and that governor permits it to open fully. Inspect the fuel-air diaphragm for leaks, dirt or wet fuel. Check the governor high idle and carburetor stop screw for low idle adjustments.

7. Slow Cranking Speed

Cranking speed must be at least 150 rpm. Check condition of starting system. Make reference to Problem 24.

8. Electrical Shutoff System Failure

Make repairs or replacements as necessary.

9. Status Control Has Detected A Fault Or Has A Defect.

Refer to the Troubleshooting Section of Form No. SENR4618, Control Panel (Status-Timing) For 3500 Spark Ignited Engines.

Problem 3: Misfiring Or Running Rough

Probable Cause:

1. Ignition System Failure

a. Check the ignition transformers for loose connection, moisture, short or open circuits. Check the primary and secondary wiring. Check the spark plugs for correct type. Check the magneto. Repair or replace any component that shows signs of failure. See Problem 36.

b. Replace the Altronic Interface Module.

c. If the problem persists, replace the Timing Control Module.

2. Low Gas Pressure

Check for leaks in gas supply. Check the line pressure regulator, shutoff valve and solenoid. If two or more engines are used, be sure the common supply line is large enough. Regulator pressure should not change over the normal load range. Inspect the regulator diaphragm for leaks and valve for correct seat contact. Check gas pressure before and after the line pressure regulator. Check for restriction in balance line from carburetor to regulator.

3. Wrong Air/Fuel Ratio

Adjust for proper free oxygen in exhaust or correct differential/pressure for fuel used.

a. Make sure all connectors are tight, check for any signs of damage, or moisture in the connectors or the wiring harness.

4. Wrong Valve Clearance

Make adjustment according to subject, Valve Clearance.

5. Bent or Broken Push Rod

Replacement of push rod is necessary.

Problem 4: Stalls At Low RPM

Probable Cause:

1. Idle RPM Too Low

Increase low idle rpm.

2. Too Much Load

Check for attachment excessive loading. Reduce load and/or adjust throttle stop. If necessary, disconnect attachments and test engine.

Problem 5: Sudden Changes In Engine Speed (RPM)

Probable Cause:

1. Wrong Adjustment Or Leaky Valve

Make adjustment to the valves.

2. Exhaust Bypass System Failure

Inspect the valve. Check valve diaphragm and boost air hose for leakage. Check breather element for plugging.

3. Governor Or Linkage Adjustment Incorrect

Check to see if linkage between governor and carburetor operates smoothly and has no free play. Make adjustment to the governor and linkage as necessary.

4. Governor Failure

Look for damaged or broken springs, linkage or other components. Check governor-to-carburetor linkage or other components. Check for correct spring. Check governor oil pump and bypass valve.

Problem 6: Not Enough Power

Probable Cause:

1. Low Gas Pressure Or Gas Line Pressure Regulator Failure Or Gas Supply Line Not Large Enough

Check for leaks in gas supply. Check the line pressure regulator, shutoff valve and solenoid. If two or more engines are used, be sure the common supply line is large enough. Regulator pressure should not change over the normal load range Inspect the regulator diaphragm for leaks and valve for correct seat contact. Check gas pressure before and after the line pressure regulator. Check for restriction in balance line from carburetor to regulator.

2. Carburetor Adjustment Or Carburetor Not Working

Check all carburetor adjustments. Be sure that throttle plate is open and that governor permits it to open fully. Check the BTU content of the fuel based on lower heat value (LHV). If it is too low, a higher fuel pressure (correct spring force in the regulator), or a special carburetor may be needed. Inspect the fuel-air diaphragm for leaks, dirt or wet fuel. Check the governor high idle and carburetor stop screw for low idle adjustments.

3. Leaks In Air Induction System

Check air cleaner for restriction. Check inlet manifold pressure on turbocharger engines.

4. Too Much Valve Clearance

Make adjustments according to the subject, Valve Clearance.

5. Ignition System Failure

b. Replace the Altronic Interface Module.

c. If the problem persists, replace the Timing Control Module.

6. Defective Spark Plugs

Check type of plug used. Install correct type. Inspect for gas leaks and/or cracked porcelain. Clean and set gap of the plugs. Install new plugs if badly worn.

7. Wrong Ignition Timing

Set magneto timing (see Magneto Timing).

8. Exhaust Bypass Failure

Check the valve movement. Check the diaphragm and boost air hose for leaks. Check breather element for plugging.

9. Turbocharger Has Carbon Deposits Or Other Causes Of Friction

Inspect and repair turbocharger as necessary.

10. Deposits In The Combustion Chamber

Make a compression test on all cylinders. Any cylinder which has great difference from the others should be inspected and cleaned.

Problem 7: Too Much Vibration

Probable Cause:

1. Vibration Damper Loose

Check vibration damper for damage. Tighten bolts. If vibration damper bolt holes have damage or wear, replace with new parts.

2. Pulley Or Vibration Damper Has A Defect

Install a new pulley or vibration damper.

3. Engine Supports Are Loose, Worn, Or Have A Defect

Tighten all mounting bolts. Install new components if necessary.

4. Driven Equipment Is Not In Alignment Or Is Out Of Balance

Check Alignment and balance, make corrections as needed.

5. Misfiring Or Running Rough

Make reference to Problem 3.

Problem 8: Loud Combustion Noise (Sound) (Indicated by Timing Control)

Probable Cause:

1. Gas Octane Rating Too Low

Use recommended gas.

2. Detonation

Make reference to Problem 30.

3. Improper Valve Train Operation

Make reference to Problem 13, 14 & 15.

Problem 9: Loud Noise (Clicking) From Valve Compartment (possibly indicated by Timing Control)

Probable Cause:

1. Broken Valve Spring(s) Or Locks

Install new parts where necessary. Broken locks can cause the valve to slide into the cylinder. This will cause much damage.

2. Not Enough Lubrication

Check lubrication in valve compartment. There must be a strong flow of oil at engine high rpm, but only a small flow of oil at low rpm. Oil passages must be clean, especially those sending oil to the cylinder head.

3. Too Much Valve Clearance

Make adjustments according to the subject Valve Clearance.

4. Damage to Valve(s)

Make a replacement of the valve(s) as necessary.

5. Damaged Camshaft Lobe Or Valve Lifter

Make reference to Problem 13.

Problem 10: Oil In Cooling System

Probable Cause:

1. Defect In Core Of Oil Cooler

Install a new core in the oil cooler.

2. Defect In Head Gasket Or Water Seals

Check cylinder liner projection. Install a new head gasket and new water seals in the spacer plate. Tighten the bolts that hold the cylinder head according to Specifications.

Problem 11: Mechanical Noise (Knock) In Engine

Probable Cause:

1. Failure Of Bearing For Connecting Rod

Inspect the bearing for the connection rod and the bearing surface on the crankshaft. Install new parts where necessary.

2. Damaged Timing Gears

Install new parts where necessary.

3. Defect In Attachment

Repair or install new components.

4. Damaged Crankshaft

Install a new crankshaft.

5. Damaged Camshaft

Make reference to Problem 13.

Problem 12: Gas Consumption Too High

Probable Cause:

1. Gas System Leaks

Replacement of parts is needed at points of leakage.

2. Defective Spark Plugs

Check type of plug used. Install correct type. Inspect for gas leaks and/or cracked porcelain. Clean and set gap of the plugs. Install new plugs if badly worn.

3. Wrong Ignition Timing

Set magneto timing (see Magneto Timing).

4. Ignition System Failure

b. Replace the Altronic Interface Module.

c. If the problem persists, replace the Timing Control Module.

Problem 13: Loud Noise From Valves Or Valve Drive Components

Probable Cause:

1. Damaged Valve Spring(s)

Make replacement of damaged parts.

2. Damaged Camshaft

Make replacement of damaged parts. If replacement of Camshaft is made, new valve lifters are also necessary.

3. Damaged Valve Lifter

Make a replacement of the damaged valve lifter. Inspect camshaft lobes for damage. Look for valves that do not move freely. Make an adjustment to valve clearance according to the subject, Valve Clearance.

Problem 14: Little Movement Of Rocker Arm And Too Much Valve Clearance

Probable Cause:

1. Not Enough Lubrication

Check lubrication in valve compartment. There must be a strong flow of oil at engine high rpm, but only a small flow at low rpm. Oil passages must be clean, especially those sending oil to the cylinder head.

2. Rocker Arm Worn At Face That Makes Contact With Bridge

If there is too much wear, install new parts or rocker arms. Make adjustment of valve clearance according to the subject, Valve Clearance.

3. Bridges For Valves Worn/Incorrect Adjustment

Make an adjustment or replacement as necessary.

4. End Of Valve Stem Worn

If there is too much wear, install new valves. Make adjustment of valve clearance according to the subject, Valve Clearance.

5. Worn Push Rods

If there is too much wear, install new push rods. Make adjustment of valve clearance according to the subject, Valve Clearance.

6. Valve Lifters Worn Or Broken

If there is too much wear, install new valve lifters. Check camshaft for wear. Check for free movement of valves or bent valve stems. Make adjustment of valve clearance according to the subject, Valve Clearance.

7. Worn Cams On Camshaft

Check valve clearance. Check for free movement of valves or bent valve stems. Install a new camshaft. Make adjustment of valve clearance according to the subject, Valve Clearance.

8. Loose Or Broken Rocker Shaft Retaining Bolt

Repair or replace as necessary.

Problem 15: Valve Rotocoil Or Spring Lock Is Free

Probable Cause:

1. Cracked Inlet Valve Rotocoil

Check for causes for engine overspeed.

2. Broken Locks

Broken locks can cause the valve to slide into the cylinder. This will cause much damage.

3. Broken Valve Spring(s)

Install new valve spring(s).

4. Broken Valve

Replace valve and all other damaged parts.

Problem 16: Oil At The Exhaust

Probable Cause:

1. Failure Of Seal Rings In Turbocharger

Check inlet manifold for oil and make repairs to the turbocharger if necessary.

2. Too Much Oil In The Valve Compartment

Be sure that the dowel is installed in the left bolt hole of the rocker shaft. The dowel is located between the rocker shaft and valve cover base. Look at both ends of the rocker arm shaft. Be sure that there is a plug in one end.

3. Worn Valve Guides

Reconditioning of the cylinder head is needed.

4. Worn Piston Rings

Inspect and install new parts as needed.

5. Cracked Or Broken Cast Iron Band In Piston

Check for high crankcase pressure (over 3 in of water).

Problem 17: Little Or No Valve Clearance

Probable Cause:

1. Worn Valve Seat Or Face Of Valve

Make adjustment of valve clearance according to the subject, Valve Clearance. Reconditioning of cylinder head may be needed.

Problem 18: Engine Has Early Wear

Probable Cause:

1. Dirt In Lubrication Oil

Remove dirty lubrication oil. Install a new oil filter element. Put clean oil in the engine. Check oil filter bypass valve for a weak or broken spring.

2. Air Inlet Leaks

Inspect all gaskets and connections. Make repairs if leaks are found.

3. Incorrect Lubrication Oil Or Oil Change Periods For Application

Determine correct lubrication oil and oil change periods for type of application. Refer to Lubrication Section of Operation And Maintenance Guide, Form SEBU6148, and Application And Installation Guide, Form No. LEBH6154.

Problem 19: Coolant In Lubrication Oil

Probable Cause:

1. Failure Of Oil Cooler Core

Install a new core for the oil cooler. Drain crankcase and refill with clean lubricant. Install a new oil filter element.

2. Failure Of Cylinder Head Gasket

Check cylinder liner projection. Install a new head gasket and new water seals in the spacer plate. Tighten the bolts that hold the cylinder head according to Specifications.

Install a new cylinder head gasket. Tighten the bolts that hold the cylinder head, according to the Specifications.

3. Crack Or Defect In Cylinder Head

Install a new cylinder head.

4. Failure Of Cylinder Liner Seals

Replace cylinder liner seals.

5. Cracked Or Broken Cylinder Liner

Replace cylinder liner.

6. Crack Or Defect In Cylinder Block

Install a new cylinder block.

Problem 20: Exhaust Temperature Is Too High

Probable Cause:

1. Exhaust System Has A Leak

Find cause of exhaust leak. Make repairs as necessary.

2. Air Inlet Or Exhaust System Has A Restriction

Remove restriction.

3. Wrong Ignition Timing

Set magneto timing (see Magneto Timing).

4. Change In Fuel BTU

Adjust the air/fuel ratio to the new BTU.

5. To Much Load On The System

Reduce the load.

Problem 21: Engine Has Low Oil Pressure

Probable Cause:

1. Oil Level Low

Fill if needed.

2. Defect In Oil Pressure Gauge

Install new gauge.

3. Dirty Oil Filter Or Oil Cooler

Check the operation of oil filter bypass valve. Clean or install a new core for the oil cooler. Drain crankcase and refill with clean lubricant. Install a new oil filter element.

4. Too Much Clearance Between Rocker Arm Shaft And Rocker Arms

Check lubrication in valve compartment. Install new parts as necessary.

5. Oil Pump Suction Pipe Has A Defect

Replacement of pipe is needed.

6. Oil Pump Pressure Regulating Valve Does Not Close

Clean valve and housing. Install new parts as necessary.

7. Oil Pump Has A Defect

Repair or replace oil pump as necessary.

8. Too Much Clearance Between Crankshaft And Crankshaft Bearings

Inspect the bearings and install new crankshaft bearings as necessary.

9. Too Much Clearance Between Camshaft And Camshaft Bearings

Install new camshaft and camshaft bearings as necessary.

10. Broken Piston Cooling Jet

Install new jet.

Problem 22: Engine Uses Too Much Lubrication Oil

Probable Cause:

1. Plugged Crankcase Breather

Clean breather.

2. Too Much Lubrication Oil In Engine

Remove extra oil. Find where extra oil comes from. Put correct amount of oil in engine.

3. Oil Leaks

Find all oil leaks. Make repairs as needed. Check for dirty crankcase breather.

4. Oil Temperature Is Too High

Check operation of oil cooler. Install new parts if necessary. Clean the core of the oil cooler.

5. Too Much Oil In Valve Compartment

6. Worn Valve Guides

Reconditioning of the cylinder head is needed.

7. Worn Piston Rings

Install new parts if necessary.

8. Failure Of Seal Rings In Turbocharger

Check inlet manifold for oil and make repairs to the turbocharger if necessary.

Problem 23: Engine Coolant Temperature Is Too High

Probable Cause:

1. Restriction To Flow Of Coolant Through Radiator Core Tubes Or Heat Exchanger

Clean and flush radiator or heat exchanger.

2. Restriction To Air Flow Through Radiator

Remove all restrictions of flow.

3. Low Fan Speed

Check For worn or loose fan belts.

4. Not Enough Coolant In System

Add coolant to cooling system.

5. Pressure Cap Has A Defect

Check operation of pressure cap. Install a new pressure cap if necessary.

6. Combustion Gases In Coolant

Find out where gases get into the cooling system. Make repairs as needed.

7. Water Temperature Regulators (Thermostats) Or Temperature Gauge Has A Defect

Check water temperature regulators for correct operation. Check temperature gauge operation. Install new parts as necessary.

8. Water Pump Has A Defect

Make repairs to the water pump as necessary.

9. Too Much Load On The System

Reduce the load.

10. Wrong Ignition Timing

Set magneto timing (see Magneto Timing).

11. Change In Fuel BTU

Adjust the timing to the new BTU.

Problem 24: Electric Starter Motor Does Not Turn

Probable Cause:

1. Battery Has Low Output

Check condition of battery. Charge battery or make replacement as necessary.

2. Wiring Or Switch Has Defect

Make repairs or replacement as necessary.

3. Starter Motor Solenoid Has Defect

Install a new solenoid.

4. Starter Motor Has Defect

Make repair or replacement of starter motor.

5. Inside Of Engine Problem

6. Status Control Has Detected Fault Or Has Defect

Refer to the Troubleshooting Section of Form No. SENR4618, Control Panel (Status-Timing) For 3500 Spark Ignited Engines.

Problem 25: Alternator Gives No Charge

Probable Cause:

1. Loose Drive Belt For Alternator

Make an adjustment to put the correct tension on the drive belt.

2. Charging Or Ground Return Circuit Or Battery Connections Have A Defect

Inspect all cables and connections. Clean and tighten all connections. Make replacement of defective parts.

3. Rotor (Field Coil) Has A Defect

Install a new rotor.

4. Voltage Regulator Has A Defect

Replace voltage regulator.

5. Stator Has A Defect

Replace stator.

6. Diodes Have A Defect

Replace diode.

Problem 26: Alternator Charge Rate Is Low Or Not Regular

Probable Cause:

1. Loose Drive Belt For Alternator

Make an adjustment to put the correct tension on the drive belt.

2. Charging Or Ground Return Circuit Or Battery Connections Have A Defect

Inspect all cables and connections. Clean and tighten all connections. Make replacement of defective parts.

3. Alternator Regulator Has A Defect

Replace alternator regulator.

4. Rectifier Diodes Have A Defect

Make replacement of rectifier diode that has a defect.

5. Rotor (Field Coil) Has A Defect

Install a new rotor.

Problem 27: Alternator Charge Too High

Probable Cause:

1. Alternator Or Alternator Regulator Has Loose Connections

Tighten all connections to alternator or alternator regulator.

2. Alternator Regulator Has A Defect

Replace alternator regulator.

Problem 28: Alternator Has Noise

Probable Cause:

1. Drive Belt For Alternator Is Worn Or Has A Defect Install a new drive belt for the alternator.

2. Loose Alternator Drive Pulley

Check key groove in pulley for wear. If groove is worn, install a new pulley. Tighten pulley nut according to Specifications.

3. Drive Belt And Drive Pulley For Alternator Are Not In Alignment

Make an adjustment to put drive belt and drive pulley in correct alignment.

4. Worn Alternator Bearings

Install new bearings in the alternator.

Problem 29: Short Spark Plug Life

Probable Cause:

1. Wrong Ignition Timing

Set magneto timing (see Magneto Timing).

2. Defective Spark Plugs

Check type of plug used. Install correct type. Clean and set gap of the plugs. Install new plugs if badly worn.

3. Incorrect Spark Plug Gap

Clean and make adjustment to the plug gap.

Problem 30: Detonation

Probable Cause:

1. Wrong Ignition Timing

Set magneto timing (see Magneto Timing).

2. Wrong Air/Fuel Ratio (Low Emission Engines)

Adjust for proper free oxygen in exhaust

3. Deposits In Combustion Chamber

Remove deposits from combustion chambers.

4. High Inlet Manifold Air Temperature

Check for high engine room temperature or high temperature of water to aftercooler. Check that air has been vented from aftercooler water.

5. Overload

Reduce the load.

6. Obstructions In Aftercooler

Inspect, clean or install new aftercooler as necessary.

7. Change In Fuel BTU

Set magneto timing (see Magneto Timing) according to the new BTU.

Problem 31: Gas Supply Line Shutoff Valve Failure

Probable Cause:

1. Defect In Solenoid

Install new solenoid.

2. Wrong Electrical Rated Solenoid

Install new solenoid with correct electrical rating.

3. Defect In Wiring And/Or Connections

Correct the defect in wiring and connections.

4. Status Control Has Detected A Fault Or Has A Defect

Refer to the Troubleshooting Section of Form No. SENR4618, Control Panel (Status-Timing) For 3500 Spark Ignited Engines.

Problem 32: Air Starting Motor Turns Slowly Or Has A Loss Of Power

Probable Cause:

1. Low Supply Air Pressure

Make an increase to the air supply pressure.

2. Pressure Regulator Adjustment Not Correct

Make an adjustment to the air pressure regulator.

3. Oiler Not Working Correctly

Check the oiler, inlet hose, fitting and oil supply hose to make sure they are vacuum tight and free of leaks. Clean, make adjustments, tighten all fittings, fill oiler or make a replacement, if necessary.

4. Worn Motor Parts

Disassemble the motor and make an inspection of the parts. A guide for determining worn parts that cannot be used again is as follows

a. Install a set of new vanes if any vane is cracked, damaged or worn to the extent that its width is 32 mm (1.25 in) at either end.

b. Replace rotor bearings if any roughness or looseness is apparent in the bearings.

c. Replace rotor if the body has deep scoring that cannot be removed with the use of emery cloth.

d. Replace cylinder if there are any cracks or deep scoring.

e. Clean up end plate scoring with emery cloth placed on a flat surface.

5. Air Leakage

Check the motor for worn seals. Plug the exhaust. Apply 205 kPa (30 psi) air to the inlet and put the unit in nonflammable fluid for 30 seconds. If bubbles appear, make a replacement of the motor seals.

Problem 33: Air Starting Motor Pinion Does Not Engage With The Flywheel

Probable Cause:

1. Broken Clutch Jaws Or Other Parts

Make a replacement of the parts.

Problem 34: Air Starting Motor Runs, Pinion Engages But Does Not Turn The Flywheel

Probable Cause:

1. Broken Shafts, Gears (Flywheel Teeth) Or Clutch Jaws

Make a replacement of the parts.

Problem 35: Air Starting Motor Pinion Does Not Engage Correctly With The Flywheel

Probable Cause:

1. Dry Pinion Shaft

Remove the drive pinion and put clean grease on the drive shaft splines and drive pinion.

Problem 36: Solid State Magneto (Altronic)

Probable Cause:

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NOTICE

Both the extension assembly at the spark plug and the internal seal between the tube and the valve cover must be installed on all cylinders when running the engine. Failure to do this may allow a spark from the exposed lead to ignite crankcase vapors. Engine damage could result.

1. Missing On One Or More Cylinders:

a. Locate which cylinder(s) are missing by measuring the exhaust temperature from each cylinder with a pyrometer, or use a Timing Light to check which cylinders are not firing.

b. Find where the wire, in the primary magneto harness, (wire from magneto to transformer), is connected to the problem cylinder. See Wiring Diagrams in Systems Operation.

c. Stop the engine and disconnect the magneto harness connector from the magneto.

NOTE: All ohmmeters must be "zeroed" (adjusted to read zero when the leads are connected together) before using. Follow instructions with your meter.

d. Using an ohmmeter having a scale of RX1, connect the probes between the pin of the problem cylinder, at the magneto connector (pin in wiring harness), and a good ground. Read the resistance. The resistance should be between .1 and .2 ohms. If reading is within specification the primary circuit is not defective. Proceed to Step g. A reading of less than .1 ohm indicates grounded primary wire or shorted primary in the transformer. A reading of more than .2 ohms indicates poor connections, defective primary in transformer, or poor ground connection.

e. To locate the defect, disconnect the primary wire connector from the transformer, (wire from magneto). Connect the ohmmeter to the primary pin (A, B or C) of the transformer and ground. Check resistance again. Correct reading is .1 to .2 ohms.

Correct reading: defect in primary harness wire or connector in harness.

Incorrect reading: defective transformer or poor ground.

f. Connect the ohmmeter across the primary pins (A, B or C) of the transformer. Read the resistance. Correct reading is .1 to .2 ohms.

Correct reading: poor ground.

Incorrect reading: defective transformer.

g. Remove the transformer.

h. Using a scale of RX100 or RX1000, connect the ohmmeter between the spark plug connector and flange of the transformer. The resistance should be between 5,000 to 8,000 ohms.

Correct reading: defective spark plug, magneto or extension assembly.

Incorrect reading: defective transformer.

i. Read the resistance of the spark plug extension between the high tension outlet of the transformer to the spark plug terminal. The resistance should be less than .2 ohms.

Correct reading: possible defective spark plug.

Incorrect reading: defective spark plug extension.

2. Engine Dead And Has No Spark

a. Disconnect the "G" wire from the shutdown circuit. Try to start the engine.

Engine Starts, Defect in shutdown circuit. Repair as required.

Engine Does Not Start, Proceed to Step b.

b. Connect an ohmmeter between the "G" wire and ground.

An ohmmeter reading of infinite (500,000 ohms or greater).

1. The wire is not grounded.

2. Possible defective magneto.

A resistance indication on the ohmmeter.

1. Grounded "G" wire.

2. Defective magneto.

c. Remove the wiring harness connector from the magneto. Connect an ohmmeter between the G pin in the wiring harness connector and ground.

1. Any resistance indication means that the wire is grounded. Replace or repair as required.

2. A reading of infinite indicates that the wire is not grounded. Defective magneto. Repair or replace the magneto.

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NOTICE

Be sure to reconnect the wire to the magnetic switch and the connector to the magneto after the repairs are made.

Timing Control Module Test Procedures

NOTE: For Timing Control Module Test Procedures A and B and Troubleshooting Procedures TSP1 - TSP7, make reference to 3500 Spark Ignited Electronic Troubleshooting, Form No. SENR4612.

Timing Control Module Test Procedure A

Timing Control Module Test Procedure B

Wiring Diagrams

Refer to Form Nos. SENR4616 Electrical Protection System Energize To Run (SI-ETR) and SENR4618 Control Panel (Status-Timing) For 3500 Spark Ignited Engines, for wiring diagrams and electrical schematics. These diagrams contain point-to-point control panel wiring diagrams and also control panel wiring harness diagrams for SI Engines. This information can be helpful for the user who is not familiar with the electrical schematic-type format, or who is interested in the component position layout for replacement purposes.

Ignition System

Magneto Installation (Altronic)

Flywheel Timing Covers
(1) Cover over flywheel pointer. (2) Cover over flywheel ring gear.

NOTE: Make reference to Finding Top Center Compression Position For No. 1 Piston.

1. Remove cover (1) for timing pointer from right side of engine.

2. Remove cover (2), and use a 9S9082 Engine Turning Tool and a 1/2" drive ratchet wrench to turn the flywheel in the direction of normal engine rotation until No. 1 piston is coming up on the compression stroke.

3. Stop turning when the 25° (BTC) timing mark (4) is directly under the flywheel pointer (3).

Flywheel Timing
(3) Flywheel pointer. (4) Flywheel timing marks.

4. Make sure magneto drive coupling (6) is turned so the drive slots are at an angle (5) of 20 ± 5° from the horizontal position as shown. If necessary, remove the bolt and pull drive coupling (6) off the drive gear. Turn the coupling to the correct angle and install it back on the drive gear. Install the bolt to hold drive coupling (6) in place.

Drive Coupling Position
(5) Angle from horizontal position for drive coupling slots. (6) Drive coupling.

Magneto Timing Marks
(7) CW mark. (8) Index mark. (9) Magneto imput connector. (10) Magneto output connector.

5. With magneto off engine, turn magneto shaft until index mark (8) in timing window is at CW mark (7).

6. Install the magneto on the engine. The drive tangs of the magneto and the drive slots of drive coupling (6) must engage correctly.

7. Make final timing adjustment by rotating the magneto at the drive housing mounting and with the use of a timing light when the engine is running at rated speed.

Magneto Timing

Set Up - Adjust - Check

Before adjusting the timing, have a gas analysis test made of the fuel being used. See your Caterpillar dealer, he is equipped to make this analysis.

Set Up Magneto

Magneto timing set up should be used during the following conditions:

1. Installation of a new magneto.

2. Installation of a new SI Timing Control.

Set Up Magneto Procedure:

NOTE: See subject, Timing Control Module Test Procedure A.

1. Connect 8C9904 DDT to connector DDTC on right side of engine using 7X6170 Cable.

2. Enter the "MAG CAL MODE" (Refer to The service tool operating manual).

3. Start the engine and run up to high idle.

4. Loosen magneto fastener bolts and adjust timing 4° ahead of most desired advanced setting (refer to Recommended BTDC Timing And Fuel Gas Chart).

5. Tighten fastener bolts on magneto.

6. Enter "TIM CAL MODE" and press function key until "DES ENG TIM" is displayed. Press ALT1 KEY and then desired ENG TIM from Recommended BTDC Timing And Fuel Gas Chart.

7. Press function key until "ACT ENG TIM" is displayed. Timing should read desired timing ± 1°.

8. Remove service tool and replace the cap on DDT connector.

Adjust Magneto

Magneto Timing Adjust should be used when desired engine timing needs to be set at some value less than the preset value from Recommended BTDC Timing And Fuel Gas Chart.

Adjust Magneto Procedure:

1. Connect 8C9904 DDT to connector DDTC on right side of engine using 7X6170 Cable.

2. Start the engine and run up to high idle.

3. Enter "TIM CAL MODE" and press function key until "DES ENG TIM" is displayed. Press ALT1 KEY and then desired ENG TIM from Recommended BTDC Timing And Fuel Gas Chart.

NOTE: Timing will not retard less than 16° of original set up value.

4. Press function key until "ACT ENG TIM" is displayed. Timing should read desired timing ± 1°.

5. Remove service tool and replace the cap on DDT connector.

Timing And Fuel Charts

Check Magneto

Magneto Timing Check can be used anytime engine is running.

Check Magneto Procedure:

1. Connect 8C9904 DDT to connector DDTC on right side of engine using 7X6170 Cable.

2. Start the engine and run up to high idle.

3. Enter "STATUS MODE" and press function key until "ACT ENG TIM" is displayed.

4. Timing should read desired timing ± 1°.

NOTE: Actual timing may be checked any time while the engine is running. However timing may not equal desired timing due to ENGINE MAP SELECTION or RETARD due to detonation. See Systems Operation for further explanation.

5. Remove service tool and replace the cap on DDT connector.

Spark Plugs

Voltage to cause the spark will change with the spark plug condition and engine load. A new spark plug in an engine at low idle will take 3,000 to 6,000 volts. At full load, this voltage will be 10,000 to 18,000 volts. When the gap of the spark plug increases too much, the voltage needed will be over 20,000 volts. Spark plugs start to cause the engine to run rough (fire erratically) when the spark plug voltage needs go higher than 25,000 volts. New spark plugs have the gap set at 0.24 to 0.32 mm (.009 to .013 in). The spark plug is of a single strap design which can be regapped. Replace worn spark plugs with new ones. Always replace the spark plug gasket when a spark plug is removed and reinstalled.

NOTE: Do Not use a wire brush to clean the tip of the spark plug.

The use of 5P6584 Timing Light is an aid for finding ignition problems. Follow the instructions that come with the tool.

Spark Plug Installation
(1) Transformer assembly. (2) Extension Assembly. (3) Spark Plug.

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NOTICE

DO NOT OVERTIGHTEN the spark plugs.

Install the new spark plug and tighten to 48 ± 4 N·m (35 ± 3 lb ft).

NOTE: Cooler exhaust temperatures at the cylinder head can also be an indication of a bad ignition transformer or spark plug. A pyrometer can be used to check surface temperatures at the cylinder heads.

Control Group (Detonation Sensitive Timing)

Control Group (Detonation Sensitive Timing)
(1) Speed Sensor. (2) Flywheel housing. (3) Crank Angle Sensor. (4) Control Group. (5) Detonation Sensor.

The Control Group (4) is located on a camshaft cover on each side of the engine. The control group detects detonation through Detonation Sensor (5). The Detonation Sensor (5) consists of an accelerometer connected to a buffer module. The accelerometer produces a voltage signal proportional to engine detonation. The buffer module amplifies the signal and sends it to the Timing Control Module (TCM). There is no adjustment or calibrations for the accelerometer. Use 5P0329 Crowfoot Wrench to tighten the detonation sensor to 10 ± 2 N·m (7 ± 1 lb ft).

The Speed Sensor (1) produces a signal whenever a ring gear tooth passes it. This signal is sent to the TCM to indicate engine speed. Adjust clearance between magnetic pick-up and flywheel ring gear to 0.56 to 0.84 mm (.022 to .033 in) With the engine stopped, turn in the pick-up until it comes in contact with the teeth on the flywheel ring gear. Turn the pick-up back out 1/2 ± 1/10 turn. Tighten the locknut to 45 ± 7 N·m (35 ± 5 lb ft)

The Crank Angle Sensor (3) produces a signal once every engine revolution. This signal is sent to the TCM to indicate the crankshaft angle. The TCM determines engine timing by comparing when number 1 cylinder spark plug fires with when the crank angle signal occurs. Adjust clearance between magnetic pick-up and flywheel to 0.56 to 0.84 mm (.022 to .033 in). With the engine stopped, turn in the pick-up until it comes in contact with the rear face of the flywheel. Turn the pick-up back out 1/2 ± 1/10 turn. Tighten the locknut to 45 ± 7 N·m (35 ± 5 lb ft)

Fuel System

When a engine has restricted power it is desirable to make a quick check of the pressure in the inlet manifold. Use the 1U5470 Engine Pressure Group to determine the approximate horsepower.

1U5470 Engine Pressure Group

This tool group has a gauge to read pressure in the inlet manifold. Special Instruction, Form No. SEHS8524 is with the tool group and gives information on the use of the group. Correct engine operating adjustments must be made to get correct results from the instruments and test.

By checking pressure of the inlet manifold and comparison of that pressure with the Fuel Setting And Related Information Fiche, correct analysis can be made of engine operating efficiency. This test can be used if engine horsepower is too low, but with no other condition of engine problem.

Gas engines can burn a wide range of gaseous fuels. BTU content of fuel is a measure of the power content of the fuel. The higher BTU content fuels need less gas pressure to get a specific horsepower.

Low octane fuels burn so fast that the timing must be set back. With early timing and low octane fuel, combustion occurs before the piston goes over top center. The result of this is "knocking."

The fuel-air ratio adjustment is made by changing the gas pressure. Too much gas makes a "rich mixture" and not enough gas makes a "lean mixture." Either causes a loss of power. When Propane gas is used, the adjustment of the fuel-air ratio is more difficult to make than when natural gas is used.

The BTU HHV (high heat value) of gaseous fuels is the unit of measurement of fuel heat content. The BTU LHV (low heat value) content is more important. The combustion procedure forms carbon dioxide and water, but, the heat needed for conversion of water into vapor is lost to the engine. The heat that can be used in the fuel is the LHV of the fuel. As a rule, the LHV is 10% less than the HHV on natural gas. When BTU HHV is given, remember to change the specification to BTU LHV so the result is correct.

Make reference to the Operation and Maintenance Guide for more information on fuels.

Initial Adjustments

Carburetor Control Linkage (3161 Governor)

Linkage Adjustment
(1) Carburetor lever. (2) Throttle stop screw. (3) Upper linkage. (4) Governor lever. (5) Lower linkage.

NOTE: Right hand mounted governors and actuators are shown. On left hand mounted governors and actuators, install levers on the control shafts at the same angles from shutoff position.

1. Disconnect lower linkage assembly (5).

2. Adjust upper linkage assembly (3) to dimension "X" (length of rod measured between the rod ends) and reference angle "Y".

3. Turn throttle stop screw (2) counterclockwise until the throttle plate will close without the screw touching the stop.

4. Rotate the carburetor throttle plate to the closed position and hold. Carburetor lever (1) must be 30 degrees off horizontal in the clockwise direction.

5. Rotate the governor control shaft to the off position. Governor lever (4) must be 24 ± 5 degrees from vertical as shown.

6. Adjust and connect the lower linkage assembly (5). Linkage adjustment should now be complete. The governor is in the off (closed) position and the carburetor throttle plate is bottomed out in the throttle body.

7. Turn throttle stop screw (2) in the clockwise direction until it just makes contact when the throttle plate bottoms out in the throttle body.

8. Check linkage operation. The linkage must not bind at any position in the travel range.

Carburetor Control Linkage (EG3P Governor)

Linkage Adjustment
(1) Reference angle. (2) Reference angle. (3) Reference angle. (4) Reference angle. (5) Carburetor lever. (6) Throttle stop screw. (7) Reference dimension. (8) Upper linkage. (9) Lower linkage. (10) Actuator lever.

NOTE: Right hand mounted governors and actuators are shown. On left hand mounted governors and actuators, install levers on the control shafts at the same angles from shutoff position.

1. Disconnect lower linkage assembly (9).

2. Adjust upper linkage assembly (8) to dimension (7) (length of rod measured between the rod ends) and reference angle (4).

3. Turn throttle stop screw (6) counterclockwise until the throttle plate will close without the screw touching the stop.

4. Rotate the carburetor throttle plate to the closed position and hold. Check reference angle chart for degrees off horizontal for carburetor lever (5).

5. Rotate the actuator control shaft to the off position. Governor lever (10) must be 15 ± 5 degrees from vertical as shown.

6. Adjust and connect the lower linkage assembly (9). Linkage adjustment should now be complete. The governor is in the off (closed) position and the carburetor throttle plate is bottomed out in the throttle body.

7. Turn throttle stop screw (6) in the clockwise direction until it just makes contact when the throttle plate bottoms out in the throttle body.

8. Check linkage operation. The linkage must not bind at any position in the travel range.

Carburetor

Carburetor Adjustment
(1) Power adjustment screw.

Turn power adjustment screw (1) on the carburetor in a clockwise direction until it bottoms out, then turn the screw counterclockwise three (3) full turns for N/A engines or one (1) turn for low emission engines.

NOTE: Turn the power adjustment screw CLOCKWISE for a LEANER fuel mixture. Turn the power adjustment screw COUNTERCLOCKWISE for a RICHER fuel mixture.

Gas Pressure Regulator

Gas line pressure must be regulated for use in engines. Naturally Aspirated engines, using a gas pressure regulator, require a line pressure of 34 to 140 kPa (5 to 20 psi).

A standard turbocharged engine must have a greater working pressure of 97 to 240 kPa (14 to 35 psi).

A low emission turbocharged engine requires a gas pressure of 165 to 240 kPa (24 to 35 psi) and must be maintained by ± 1 psi throughout the operating range. The maximum line pressure which the line pressure regulator can reduce to a working pressure is 240 kPa (35 psi). If the gas pressure exceeds 240 kPa (35 psi), a second line pressure regulator of adequate flow capacity must be used ahead of the line pressure regulator on the engine.

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NOTICE

Use only properly designated Caterpillar gas pressure regulators.

The gas pressure regulator requires adjustment when the engine is installed, and when the regulator is reworked. To adjust the gas pressure regulator correctly, the 1U5470 Engine Pressure Group or a water manometer must be used to measure the differential air-fuel pressure. The specification for this differential air-fuel pressure is given in the Fuel Setting And Related Information Fiche. See the Engine Information Plate for the performance specification number.

Differential Air-Fuel Pressure Measurement (Turbocharged Engine Illustrated)
(1) Cap over regulator adjustment screw. (A) Location for pressure tap at carburetor inlet. (B) Location for pressure tap for gas pressure to the carburetor.

1. Make sure that the main gas valve is shut off.

2. Remove plug from the gas line at location (B) and plug from the elbow on the carburetor at location (A).

3. Connect the 1U5470 Engine Pressure Group or a water manometer and shutoff valve between locations (A) and (B) to measure gas pressure before starting the engine.

4. Remove cap (1), and install the correct tools, from the 8T5160 Regulator Adjusting Tool Group, for pressure setting adjustment.

5. Open the main gas valve.

6. Adjust the gas pressure regulator until there is an air-fuel differential pressure of 1.5 kPa (6 in of water). The regulator adjustment is made by turning the slotted nut. Turn the slotted nut clockwise to increase the output pressure or counterclockwise to decrease the output pressure.

7. Shut off the main gas valve, and crank the engine 10 to 15 seconds to purge unburned gas from the exhaust system. Allow the starter to cool for two minutes.

NOTE: Make reference to the Operation And Maintenance Guide for the correct starting procedures.

8. Open the main gas valve and start the engine.

9. Again adjust the gas pressure regulator to get an air-fuel differential pressure of 1.5 kPa (6 in of water).

NOTE: If a manometer is used to check the air-fuel differential pressure, a shut-off valve must be installed between the carburetor and manometer. This shut off valve must be in the OFF position before the engine is stopped. This prevents manometer fluid from getting into the inlet of the carburetor.

Engine Timing

1. After the gas pressure regulator adjustment is completed, start the engine. Let the engine warm up to normal operating temperatures at minimum load.

2. Set the engine at rated speed with minimum load and adjust engine timing to the correct value. See subject, Magneto Timing in the Ignition System section for the correct specifications.

Adjustments For Unknown BTU Fuels (Not for Low Emission Engines)

Engines Rated At Variable Speed

1. Make the needed adjustments given in the Initial Adjustments section, so the engine can be started.

2. Install an accurate tachometer on the engine.

3. Start the engine and put under constant fixed load. Load should be as near full as possible.

4. Physically lock the carburetor throttle plate in position while the engine is operating.

5. Disconnect the governor linkage.

6. Turn the carburetor power adjustment screw to get maximum engine rpm. Maximum engine rpm can be found best by starting with a lean mixture, and slowly increasing richness to reach maximum rpm.

7. Reduce the maximum obtainable rpm by 3%. This is done by leaning the mixture. Turn the carburetor power adjustment screw clockwise. This will give the correct air fuel ratio.

8. Reconnect the governor linkage, and unlock the throttle plate.

9. If the differential pressure setting is desired, use the 1U5470 Engine Pressure Group or a water manometer and follow the procedure in the Initial Adjustments section.

Engines Rated At Constant Speed

1. Make the needed adjustments given in the Initial Adjustments section, so the engine can be started.

2. Install an accurate tachometer on the engine.

Check Inlet Manifold Pressure
(1) Plug or sending unit for manifold air temperature gauge.

3. Use the 1U5470 Engine Pressure Group to read inlet manifold pressure at location (1).

4. Start the engine and put it under constant fixed load. Load should be 1/2 to 3/4 rated load capacity. Allow governor to keep engine at constant rpm.

5. Turn the carburetor power adjustment screw until minimum inlet manifold pressure is obtained.

6. After minimum inlet manifold pressure is obtained, turn the carburetor power adjustment screw clockwise until inlet manifold pressure is increased by one inch of mercury.

7. At this point the adjustment is complete. If the differential pressure setting is desired, use the 1U5470 Engine Pressure Group or a water manometer and follow the procedure in the Initial Adjustments section.

Power Adjustment Screw Setting

The carburetor power adjustment screw is usually set at three (3) full turns open from the full off position for N/A engines. For low emission engines set power adjustment screw at one (1) turn open from the full off position. Leave the regulator in a fixed position and carefully adjust the power adjustment screw for a drop in rpm, or increase in inlet manifold pressure, as explained in the two adjustment procedures in this section.

NOTE: Turn the power adjustment screw CLOCKWISE for a LEANER fuel mixture. Turn the power adjustment screw COUNTERCLOCKWISE for a RICHER fuel mixture.

After adjustment of the power adjustment screw, loads should be applied to the engine to make sure the new setting is not causing poor engine operation due to a restriction of gas flow.

Balance Line

Turbocharged engines have a balance line from the carburetor to the line pressure regulator. The balance line transmits manifold air pressure to the upper side of the regulator diaphragm. This force, added to the spring force, makes sure that gas pressure to the carburetor will always be greater than inlet air pressure, regardless of load conditions. A turbocharged engine will not develop full power with the balance line disconnected.

Adjustments For Known BTU Fuels (Not for Low Emission Engines)

1. Make the needed adjustments given in the Initial Adjustments section, so the engine can be started. Use the HIGH and LOWER Heating Value Fuels graphs to find the differential pressure setting which will give the correct air fuel ratio.

2. Find the correct differential pressure to use from the graphs.

Heat Value Charts

3. Start the engine and adjust gas pressure regulator to give the correct differential pressure with engine at low idle.

4. With the engine at normal operating temperature, increase load to 1/2 to 3/4 rated load at rated speed.

5. Adjust the carburetor power adjustment screw to obtain a minimum inlet manifold pressure for turbocharged engines (maximum vacuum on Naturally Aspirated Engines).

6. After a minimum inlet manifold pressure is obtained, turn the screw clockwise until the inlet manifold pressure is increased by one (1) inch of mercury (Turbocharged engines) or the vacuum is decreased (Naturally Aspirated engines) by one (1) inch of mercury.

7. An alternate method is to set the carburetor power adjustment screw at rated speed and load by using an oxygen meter.

Attach the oxygen meter to the exhaust elbow on all naturally aspirated engines. Adjust the power adjusting screw until a 2% oxygen reading is obtained.

Low Emission Engine Settings

An oxygen meter is required to make the following adjustments to the carburetor.

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NOTICE

A low emission engine cannot be operated above 1/2load at rated speed until the oxygen level in the exhaust has been adjusted. Failure to properly adjust a low emission engine can cause detonation and severe engine damage, or shutdown the engine by SI Timing Control.

1. After making the initial carburetor and pressure regulator adjustments, the engine can be started and allowed to warm up to normal operating temperatures at minimum load. See the Initial Adjustments section.

2. Set the engine at rated speed with minimum load and adjust the engine timing to the correct value. See subject, Magneto Timing in the Ignition System section for the correct specifications.

3. After the timing has been correctly adjusted, increase load to 1/2 rated load at rated speed.

4. Connect an oxygen meter to the exhaust manifold at a point before the turbocharger and turn the carburetor power adjustment screw to obtain a preliminary oxygen level that is 1.5 less than the desired level at rated load and speed.

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NOTICE

The engine cannot be misfiring while setting the oxygen level, or a false reading will be obtained. Misfire can be detected with a hydrocarbon analyzer or by monitoring the oxygen level on each bank of the engine. In addition, the SI Timing Control can register detonation falsely and retard the timing and cause shutdown.

5. Increase the load to rated load and speed, and set the oxygen level as follows:

a. Refer to the appropriate chart for your engine configuration to determine the proper oxygen level.

b. Adjust the carburetor power adjustment screw until the oxygen level matches the number found on the oxygen emission graph.

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NOTICE

It is important that the oxygen levels read as outlined in step 5b above. If the mixture is too rich (oxygen levels below the % level determined in step 5b) there could be possible engine detonation which could cause the engine timing to retard and shutdown. If the mixture is too lean (oxygen levels above the percent measured in step 5b) power loss, poor response, part throttle instability, misfire or a combination of these problems could result.

6. After 150 hours of operation, the adjustments should be checked and readjusted if necessary, due to the break-in period of the engine.

Oxygen Emissions Graphs

Compression Ratio ... 9:1

Type of Duty ... Continuous

Rated kW ... 858

Rated bhp ... 1150

Rated rpm ... 1200

Air Inlet And Exhaust System

Restriction Of Air Inlet And Exhaust

There will be a reduction of horsepower and efficiency of the engine if there is a restriction of the air inlet or exhaust system.

Air flow through the air cleaner must not have a restriction of more than 381 mm (15 in) of water difference in pressure.

Back pressure from the exhaust (pressure difference measurement between exhaust outlet elbow and atmosphere) must not be more than 686 mm (27 in) of water for naturally aspirated and turbocharger engines (measured between the turbocharger outlet and atmosphere).

Inlet Manifold Temperature - (All Aftercooling Systems)

Location To Check Inlet Manifold Temperature
(1) Plug or sending unit for inlet manifold air temperature gauge.

Check the inlet manifold air temperature under full operating conditions. The inlet temperature should be below the maximum limits shown in the chart.

If the inlet temperature is above the maximum limit, check the separate circuit aftercooling thermostat for proper operation.

Follow the manufacturer's maintenance recommendations to service the air-to-air aftercooler and temperature control system.

Measurement Of Exhaust Temperatures

Use the 1U8865 Infrared Thermometer Group to check exhaust temperature. Special Instruction, Form No. NEHS0510 is with the tool group and gives instructions for the test procedures.

A pyrometer can also be used to check the temperatures at the cylinder heads.

Exhaust Bypass Valve

Location To Check Inlet Manifold Temperature
(1) Plug or sending unit for inlet manifold air temperature gauge.

On turbocharged engines, operation of the exhaust bypass valve on engine, can be checked by measuring inlet manifold pressure at location (1) with the 1U5470 Engine Pressure Group. Too much or not enough pressure is an indication of a valve not operating correctly.

For the correct air inlet specifications, see the Engine Information Plate for the performance specification number and make reference to the Fuel Setting And Related Information Fiche.

The exhaust bypass valve is preset at the factory. Adjustments may be necessary due to: replacement of the bypass valve, altitude or changes in ambient temperature conditions.

Exhaust Bpass Valve Typical Example
(1) Air inlet port. (2) Springs. (3) Cover assembly. (4) Plug. (5) Jam nut. (6) Screw. (7) Poppet valve. (8) Breather location. (9) Base assembly. (10) Diaphragm. (11) Diaphragm retainer.

Replacement Proceedure For Adjustable Exhaust Bypass Valve

The following steps are for replacement of the exhaust bypass valve.

NOTE: When replacing an adjustable bypass valve, the part will be marked "NON-CURRENT SETTING".

1. Remove plug (4) and loosen jam nut (5).

2. Cross reference the prescribed valve displacement from the charts in Adjustable Bypass Valve Settings section of this service manual by locating: engine model, speed (rpm), separate circuit aftercooler water temperature (SCAC) and maximum Brake Kilowatt (BkW) output for the engine.

3. Place the bypass valve in the bench fixture and measure zero gauge pressure valve position. Apply 100 kPa (14.5 psi) air pressure to air inlet ("boost inlet") port (1). If the engine is a Low Emission version, apply 150 kPa (22 psi).

4. Turn the bypass valve adjustment screw (6) until the bypass valve movement meets the prescribed valve displacement from the zero gauge pressure position. Back out the screw to increase displacement. Turn the screw in to decrease displacement.

To eliminate false bypass valve settings, remove the "Boost" pressure. Reapply pressure and verify the bypass valve displacement.

5. Tighten jam nut (5) and install plug (4) after the setting is complete.

Modification or Adjustment Proceedure For Adjustable Exhaust Bypass Valve

The following steps are for the adjustment of the exhaust bypass valve to compensate for altitude and/or ambient air temperature.

1. Remove the end cap and loosen the jam nut.

3. Decrease the prescribed value displacement by the amount referenced in the Altitude And Temperature Table For Adjustable Bypass Valves. This chart is an altitude and ambient temperature compensation table for the adjustable bypass valve.

4. Place the bypass valve in the bench fixture and measure zero gauge pressure valve position. Apply 100 kPa (14.5 psi) air pressure to air inlet ("boost inlet") port (1). If the engine is a Low Emission version, apply 150 kPa (22 psi).

5. Turn the bypass valve adjustment screw (6) until the bypass valve movement meets the altitude and temperature compensated prescribed valve displacement from the zero gauge pressure position. Back out the screw to increase displacement. Turn the screw in to decrease displacement.

To eliminate false bypass valve settings, remove the "Boost" pressure. Reapply pressure and verify the bypass valve displacement.

6. Tighten jam nut (5) and install plug (4) after the setting is complete.

Modification or Adjustment Procedure For Adjustable Exhaust Bypass Valve

The following steps are for continuous part load operation or richer than 2 grams/bhp-hr NOx settings on low emission engines.

1. Readjust the adjustable bypass valve so that the engine has 3 to 5% power margin at the maximum continuous power output for the specific application.

2. For engines operating continuously at less than the maximum rating, fuel consumption can be improved by operating the engine near full throttle (55 to 75°). This is typically a 10 to 20 kPa (1.5 to 2.9 psi) pressure drop measured from the compressor outlet to the intake manifold or plenum. Setting engines near full throttle will also help the governing response and stability.

3. When low emission engines are operated at higher than the nominal NOx setting, the bypass valve should be adjusted to allow proper power margin along with correct engine response and stability. Richening the engine from 2 to 5 grams/bhp-hr NOx (decreasing exhaust oxygen by approximately 1%) should be compensated with a 4 mm increase in bypass valve displacement.

For each 1% decrease in exhaust oxygen the bypass valve displacement should increase 4 mm. In addition, power margin should be decreased as discussed in Step 2.

3508 SITA Adjustable Bypass Valve Settings

3508 Low Emission (4P2455)

Turbocharger group ... 7C4470

Bypass valve group ... 7E4299

Fuel ... pipeline natural gas

3508 Standard (9Y0759)

Turbocharger group ... 7E8465

Bypass valve group ... 7E4299

Fuel ... pipeline natural gas

3508 Standard (9Y0759)

Turbocharger group ... 7E8465

Bypass valve group ... 7E4299

Fuel ... propane

Altitude And Temperature Table For Adjustable Bypass Valves

Checking Aftercooler Operation

8T0470 Thermistor Thermometer Group

Use the 8T0470 Thermistor Thermometer Group to check the operation of the aftercooler. Special Instruction, Form No. SEHS8446 gives the procedures for using the 8T0470 Thermistor Thermometer Group.

Crankcase (Crankshaft Compartment) Pressure

Pistons or rings that have damage can be the cause of too much pressure in the crankcase. This condition will cause the engine to run rough. There will also be more than the normal amount of fumes (blow-by) coming from the crankcase breather. The breather can then become restricted in a very short time, causing oil leakage at gaskets and seals that would not normally have leakage. Other sources of blow-by can be worn valve guides or turbocharger seal leakage.

8T2700 Blowby/Air Flow Indicator Group

Compression

An engine that runs rough can have a leak at the valves, or valves that need adjustment. Run the engine at the speed that gives rough running. To find a cylinder that has low compression or does not have good ignition, remove spark plug wires one at a time. This will stop the flow of current to that cylinder. Do this for each cylinder until a removed wire is found that makes no difference in engine rough running. Be sure to install the wire for the spark plug after each cylinder test before the next wire is removed. This test can also be an indication that the spark plug is bad, so more checking of the cylinder will be needed.

Cooler exhaust temperatures at the cylinder head can also be an indication of a bad ignition transformer or spark plug. A pyrometer can be used to check surface temperatures at the cylinder heads.

The 1U8865 Infrared Thermometer Group can also be used to check exhaust temperature. Special Instruction, Form No. NEHS0510 is with the tool group and gives instructions for the test procedures.

Condition of the valves, valve seats, pistons, piston rings and cylinder liners can be tested by putting air pressure in the cylinder. Special Instruction Form No. GMG00694 gives instructions for the test procedure.

Removal of the heads and inspection of the valves and valve seats is necessary to find those small defects that do not normally cause a problem. Repair of these problems is normally done when reconditioning the engine.

Cylinder Heads

The cylinder heads have valve seat inserts, valve guides and bridge dowels that can be removed when they are worn or have damage. Replacement of these components can be made with the tools that follow.

Valves

Valve removal and installation is easier with use of the 1P3527 Valve Spring Compressor Assembly.

Valve Seat Inserts

To remove and install valve seat inserts, use the 6V4805 Valve Seat Extractor Group. For installation, lower the temperature of the insert before it is installed in the head.

Valve Guides

Tools needed to remove and install valve guides are the 5P1729 Bushing and 7M3975 Driver. The counterbore in the driver bushing installs the guide to the correct height. Use a 1P7451 Valve Guide Honing Group to make a finished bore in the valve guide after installation of the guide in the head. Special Instruction, Form No. SMHS7526 gives an explanation for this procedure. Grind the valves after the new valve guides are installed.

Checking Valve Guide Bores

Use the 5P3536 Valve Guide Gauge Group to check the bore of the valve guides. Special Instruction, Form No. GMG02562 gives complete and detailed instructions for use of the 5P3536 Valve Guide Gauge Group.

5P3536 Valve Guide Gauge Group

Bridge Dowels

Use a 5P0944 Dowel Puller Group with a 5P0942 Extractor to remove the bridge dowels. Install a new bridge dowel with a 6V4009 Dowel Driver. This dowel driver installs the bridge dowel to the correct height.

Engine Rotation

SAE standard engine crankshaft rotation is counterclockwise as seen from the flywheel end of the engine.

Finding Top Center Compression Position For No. 1 Piston

Timing Bolt Location (Typical Illustration)
(1) Cover. (2) Timing bolt. (3) Plug in timing bolt hole.

1. Remove cover (1) and the timing hole plug from the right front side of the flywheel housing. On some engines there is a cover and timing bolt hole located on the left side, also.

2. Put timing bolt (2) [long bolt that holds cover (1) on the flywheel housing] through the timing hole in the flywheel housing. Use the 9S9082 Engine Turning Tool (4) and a 1/2" drive ratchet wrench to turn the engine flywheel in the direction of normal engine rotation until the timing bolt engages with the threaded hole in the flywheel.

NOTE: If the flywheel is turned beyond the point that the timing bolt engages in the threaded hole, the flywheel must be turned opposite normal engine rotation approximately 30 degrees. Then turn the flywheel in the direction of normal engine rotation until the timing bolt engages with the threaded hole. The reason for this procedure is to make sure the play is removed from the gears when the No. 1 piston is put on top center.

3. Remove the valve cover for the No. 1 cylinder head.

Timing Bolt Installation (Typical Illustration)
(2) Timing bolt. (4) 9S9082 Engine Timing Tool.

4. The intake and exhaust valves for the No. 1 cylinder are fully closed if No. 1 piston is on the compression stroke and the rocker arms can be moved by hand. If the rocker arms cannot be moved and the valves are slightly open, the No. 1 piston is on the exhaust stroke. Make reference to chart for Crankshaft Positions For Valve Clearance Setting to find the correct cylinder(s) to be checked/adjusted and for the stroke position of the crankshaft when the timing bolt has ben installed in the flywheel.

NOTE: When the actual stroke position is identified, and the other stroke position is needed, it is necessary to remove the timing bolt from the flywheel and turn the flywheel 360° in the direction of normal engine rotation.

Cylinder And Valve Location (3516 shown)

Camshaft Timing

Timing Check

Location Of Timing Pins
(1) Timing hole. (2) Timing pin. (3) Cover.

1. Remove rear camshaft cover (3) from both sides of the engine.

2. Make reference to Finding Top Center Position For No. 1 Piston.

NOTE: Since both rear camshaft covers have to be removed to check the timing, it is not necessary to remove No. 1 valve cover to find the compression stroke when timing bolt is installed in flywheel.

3. With timing bolt installed in flywheel, on each side of the engine, look at rear of camshaft to see if timing groove (slot) is visible on the camshaft. If it is visible, No. 1 piston is on the compression stroke. If it is not visible, feel the backside of the camshaft for the groove. If the groove is at the back of the camshaft, the flywheel will have to be turned 360° to put No. 1 piston on the compression stroke.

Installating Of Timing Pins
(2) Timing pin (4) Camshaft (L.H.).

4. With timing bolt installed in the flywheel, No. 1 piston is on compression stroke, remove timing pins (2) from their storage positions.

5. Install timing pins (2) through holes (1) in the engine block and into the groove (slot) in camshaft (4) on each side of the engine. For the engine to be timed correctly, the timing pins must fit into the groove of each camshaft.

6. If timing pins (2) do not engage in the grooves of both camshafts, the engine is not in time, and one or both camshafts must be adjusted.

Both camshafts are adjusted the same way. See Timing Adjustment for the procedure to put the camshafts in time with the crankshaft.

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NOTICE

If a camshaft is out of time more than 18 degrees (approximately 1/2 the diameter of timing pin out of groove), the valves can make contact with the pistons. This will cause damage that will make engine repair necessary.

Timing Adjustment

NOTE: Before any timing adjustments are made, the timing must be checked first to see if adjustment is necessary. See subject Timing Check for this procedure.

After Timing Check procedure is complete, timing bolt will be engaged in flywheel with No. 1 piston at top center (TC) position.

Loosen Rocker Shafts
(1) Bolt. (2) Rocker shaft.

1. Remove all valve covers on the same side of the engine that camshaft needs adjustment. Now loosen bolts (1) [that hold all rocker shafts (2) to valve cover bases] until all rocker arms are free from the valves.

NOTE: The above procedure must be done before the camshaft drive gear is pulled off the camshaft taper.

Remove Cover Left Hand side
(3) Cover. (4) Magneto. (5) Housing assembly. (6) Oil line.

2. Remove cover (3) on the left side of the engine.

3. Disconnect the wiring harness and remove magneto (4) from housing assembly (5) on the right side of the engine.

4. Remove oil line (6). Remove housing assembly (5) from the right side of the engine.

Camshaft Drive Gear
(7) Gear (camshaft drive). (8) Bolt. (9) Plate.

5. Remove bolt (8) and plate (9) that holds camshaft drive gear (7) on the camshaft.

Magneto Drive Gear
(10) Gear (camshaft drive). (11) Bolt. (12) Gear (magneto drive).

6. Remove bolt (10) and magneto drive gear (11) from the right camshaft.

Remove Camshaft Drive Gears
(A) 1P0820 Hydraulic Puller. (9) Plate.

7. Use tooling (A) to remove the camshaft drive gears (7) and (10) from the camshafts.

8. Put three 5H1504 Washers (3/4" Hardened) behind plate (9) that holds the camshaft drive gear on the camshaft and install the plate and bolt (8) on the camshaft.

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NOTICE

Do not apply more than 51 675 kPa (7500 psi) pressure to 1P0820 Hydraulic Puller. 8B7559 Adapters are rated at 6 1/2 ton each and 1P0820 Hydraulic Puller is rated at 17 ton at 68 900 kPa (10 000 psi). If too much pressure is applied, the gear may be damaged.

9. Use the 8B7559 Adapters and needed parts from the 8B7548 Push-Puller to install the 1P0820 Hydraulic Puller on the camshaft drive gear. Apply 51 675 kPa (7500 psi) to puller and hit the screw until the camshaft drive gear is free of the camshaft taper. Remove the tooling and the camshaft drive gear from the camshaft.

Camshaft Timing
(13) Timing pin.

10. Remove timing pins (13) from the storage position (under the rear camshaft covers) on each side of the engine.

11. Turn the camshafts until timing pins (13) can be installed through timing holes and into the grooves (slots) in the camshaft.

12. Install camshaft drive gears (7) and (10) as follows:

a. Pin both camshafts and put camshaft drive gears in position on each camshaft taper.

b. For correct timing, all gear clearance (backlash) must be removed. Turn the camshaft drive gears in the same direction as crankshaft rotation and hold in this position.

c. Install plate (9) and magneto drive gear (12) to hold the camshaft drive gears to each camshaft.

d. Tighten bolts (8) and (11) in steps to a torque of ... 360 ± 50 N·m (265 ± 35 lb ft)

e. Hit bolts (8) and (11) and again tighten the bolts to a torque of ... 360 ± 50 N·m (265 ± 35 lb ft)

NOTE: If necessary, repeat Step 12e until the bolts hold torque (cannot be moved) to make sure the drive gears are in full contact with the taper on the camshafts.

Install Magneto Drive
(5) Housing assembly. (15) Magneto drive coupling.

13. Install the gasket and magneto drive housing (5) on the flywheel housing. Use two 3/8"-16 NC × 6 in long guide bolts as shown. Turn magneto drive coupling (15) to put the drive slots at the correct angle. See Magneto Installation for the correct drive slot angle.

Install Magneto
(3) Cover. (4) Magneto. (5) Housing assembly. (6) Oil line.

14. Install oil line (6) and magneto (4) on housing assembly (5). Connect the wiring harness to the magneto.

NOTE: See Magneto Timing for the correct installation and adjustment of the magneto.

15. Install the gasket and cover (3) on the left side of the flywheel housing.

16. Remove timing pins (13) from the camshafts. Install timing pins (13) in their storage positions. Install the covers over the camshafts and timing pins.

17. Remove the timing bolt from the flywheel housing

18. Install the 5M6213 Plug in the flywheel housing timing hole. Remove the engine turning pinion and install the cover and gasket.

19. Make sure the rocker arms are engaged correctly with the push rods. Tighten the bolts to hold all of the rocker shafts in position, to a torque of 109 ± 14 N·m (80 ± 10 lb ft).

20. Make adjustments of the valve clearance. See Valve Clearance Setting for the correct procedure.

Bridge Adjustment

When the cylinder head is disassembled, keep the bridges with their respective valves. To make an adjustment to the bridges, use the procedure that follows:

NOTE: The bridges can be adjusted without removal of the rocker arms and shafts. Valves must be fully closed when adjustment is made. To find when valves are fully closed, see subject, Finding Top Center Position For No. 1 Piston and chart Crankshaft Positions For Valve Clearance Setting.

Remove Valve Covers
(1) Transformer. (2) Tube. (3) Valve cover.

1. Disconnect the wiring harness and remove transformers (1) from valve covers (3).

2. Remove the extension from the spark plugs. Remove valve covers (3) from the valve cover bases.

3. If necessary, remove the bolt and retainer that hold tubes (2) in position, and pull the tubes from each cylinder head.

Loosen Adjustment Screw Locknut
(4) Adjustment screw. (5) Locknut. (6) Bridge.

4. Loosen locknut (5) on adjustment screw (4), and turn adjustment screw (4) out (loosen) several turns.

5. Put a force of 5 to 45 N (1 to 10 lb) by hand on top of the rocker arm directly above the center of bridge (6).

6. Turn adjustment screw (4) clockwise until it just makes contact with the valve stem. Then turn the adjustment screw 20 to 30° more in a clockwise direction to make the bridge straight on the dowel, and to make compensation for the clearance in the threads of the adjustment screw.

Bridge Adjustment

Tighten Locknut

7. Hold adjustment screw (4) in this position, and tighten locknut (5) to 30 ± 4 N·m (22 ± 3 lb ft).

8. Make sure valve clearance is correct. See subject, Valve Clearance for the procedures to use.

9. Install tubes (2) and the bolts and retainers in each cylinder head.

10. Install the valve covers, the spark plug extensions and the transformers.

11. Connect the wiring harness to transformers (1).

Crankshaft Positions For Valve Clearance Setting

Cylinder And Valve Location (3516 shown)

Valve Clearance

Valve clearance (lash) is measured between the rocker arm and the bridge for the valves. All clearance measurements and adjustments must be made with the engine stopped, and with the valves FULLY CLOSED.

Valve Clearance Check

When the valve clearance is checked, adjustment is NOT NECESSARY if the measurement is in the range given in the chart for Valve Clearance Check: Engine Stopped. However, it is the recommendation of Caterpillar that the valve clearance setting is to be made at the initial (first) oil change interval. Future checks and adjustments should be made every every 2000 hours thereafter.

If the measurement is not within this range, or if the service meter indication is at the specified interval, adjustment is necessary. See subject, Valve Clearance Adjustment.

Valve Clearance Adjustment

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NOTICE

Due to normal changes (break-in effects) of new or rebuilt engines, the recommended first interval for valve clearance setting is at the initial (first) oil change interval.

Use the procedure that follows for adjustment of the valves:

1. Put No. 1 piston at top center (TC) position. Make reference to Finding Top Center Position For No. 1 Piston.

2. With No. 1 piston at top center position of the correct stroke, adjustment can be made to the valves as shown in the chart Crankshaft Positions For Fuel Timing And Valve Clearance Setting.

NOTE: Before any actual adjustments are made, tap (hit lightly) each rocker arm (at top of adjustment screw) with a soft hammer to be sure that the lifter roller is seated against the camshaft base circle.

3. Make an adjustment to valve bridge. See subject, Bridge Adjustment.

4. Loosen the locknut for the push rod adjustment screw. If there is not enough clearance for feeler gauge between rocker arm and bridge contact surface, turn the adjustment screw counterclockwise to increase the valve clearance.

5. Put a feeler gauge of the correct dimension between the rocker arm and bridge contact surface. Turn the adjustment screw clockwise until the valve clearance is set to the specifications in the chart Valve Clearance Setting: Engine Stopped.

Valve Clearance Adjustment

6. After each adjustment, tighten the nut for the adjustment screw to a torque of 70 ± 15 N·m (50 ± 11 lb ft) and check the adjustment again.

Tighten Adjustment Screw Locknut

7. Remove the timing bolt and turn the flywheel 360° in the direction of engine rotation. This will put No. 1 piston at top center (TC) position on the opposite stroke. Install the timing bolt in the flywheel.

8. With No. 1 piston at top center position of the opposite stroke, adjustment can be made to the remainder of the valves as shown in the chart Crankshaft Positions For Fuel Timing And Valve Clearance Setting.

9. Repeat Steps 3, 4 and 5 for these valve adjustments.

10. Remove the timing bolt from the flywheel when all valve clearances have been adjusted.

Lubrication System

One of the problems in the list that follows will generally be an indication of a problem in the lubrication system for the engine.

Too Much Oil ConsumptionOil Pressure Is LowOil Pressure Is HighToo Much Bearing WearIncreased Oil Temperature

Too Much Oil Consumption

Oil Leakage on Outside of Engine

Check for leakage at the seals at each end of the crankshaft. Look for leakage at the oil pan gasket and all lubrication system connections. Check to see if oil comes out of the crankcase breather. This can be caused by combustion gas leakage around the pistons. A dirty crankcase breather will cause high pressure in the crankcase, and this will cause gasket and seal leakage.

Oil Leakage Into Combustion Area of Cylinders

Oil leakage into the combustion area of the cylinders can be the cause of blue smoke. There are four possible ways for oil leakage into the combustion area of the cylinders:

1. Oil leakage between worn valve guides and valve stems.

2. Worn or damaged pistons, piston rings, or dirty oil return holes in the piston.

3. Compression ring and/or intermediate ring not installed correctly.

4. Oil leakage past the seal rings in the impeller end of the turbocharger shaft.

Too much oil consumption can also be the result if oil with the wrong viscosity is used. An increase of engine temperature can also affect the oil viscosity.

Measuring Engine Oil Pressure

An oil pressure gauge that has a defect can give an indication of low or high oil pressure.

1U5470 Engine Pressure Group

The 1U5470 Engine Pressure Group can be used to measure the pressure in the system. This tool group has a gauge to read pressure in the oil manifold. Special Instruction, Form No. SEHS8524 is with the tool group and gives instructions for its use.

Oil Gallery Plug
(1) Plug.

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Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.

Oil pressure to the camshaft and main bearings should be checked on each side of the cylinder block at oil gallery plug (1). With the engine at operating temperature, minimum oil pressure at full load rpm should be approximately 280 kPa (40 psi), and minimum oil pressure at low idle rpm should be approximately 140 kPa (20 psi).

Oil Pressure Is Low

Crankcase Oil Level

Check the level of the oil in the crankcase. Add oil if needed. It is possible for the oil level to be too far below the oil pump supply tube. This will cause the oil pump not to have the ability to supply enough lubrication to the engine components.

Oil Pump Does Not Work Correctly

The inlet screen of the supply tube for the oil pump can have a restriction. This will cause cavitation (low pressure bubbles suddenly made in liquids by mechanical forces) and a loss of oil pressure. Air leakage in the supply side of the oil pump will also cause cavitation and loss of oil pressure. If the bypass valve for the oil pump is held in the open (unseated) position, the lubrication system can not get to maximum pressure. Oil pump gears that have too much wear will cause a reduction in oil pressure.

Oil Filter Bypass Valve

If the bypass valve for one (or more) of the oil filters is held in the open position (unseated) because the oil filters have a restriction, a reduction in oil pressure can result. To correct this problem, remove and clean each bypass valve and bypass valve bore. Install new Caterpillar oil filters to be sure that no more debris makes any of the bypass valves stay open.

Too Much Clearance at Engine Bearings or Open Lubrication System (Broken or Disconnected Oil Line or Passage)

Components that are worn and have too much bearing clearance can cause oil pressure to be low. Low oil pressure can also be caused by an oil line or oil passage that is open, broken or disconnected.

Piston Cooling Jets

When engine is operated, cooling jets direct oil toward the bottom of the piston to cool the piston and also provide lubrication for the piston pin. If a jet is broken, plugged or installed wrong, seizure of the piston will be caused in a very short time.

Oil Pressure Is High

Oil pressure will be high if the bypass valve for the oil pump can not move from the closed position.

Too Much Bearing Wear

When some components of the engine show bearing wear in a short time, the cause can be a restriction in an oil passage.

If the gauge for oil pressure shows enough oil pressure, but a component is worn because it can not get enough lubrication, look at the passage for oil supply to the component. A restriction in a supply passage will not let enough lubrication get to a component, and this will cause early wear.

Increased Oil Temperature

Look for a restriction in the oil passages of the oil cooler. If the oil cooler has a restriction, the oil temperature will be higher than normal when the engine is operated. The oil pressure of the engine will not get low just because the oil cooler has a restriction.

Also check the oil cooler bypass valve to see if it is held in the open position (unseated). This condition will let the oil through the valve instead of the oil cooler, and oil temperature will increase.

Gauges For Oil Pressure

An oil pressure gauge or a sender that has a defect can give an indication of low or high oil pressure.

The 1U5470 Engine Pressure Group can be used to make a comparison with instrument panel gauges.

Cooling System

This engine has a pressure type cooling system. A pressure type cooling system gives two advantages. The first advantage is that the cooling system can have safe operation at a temperature that is higher than the normal boiling (steam) point of water. The second advantage is that this type system prevents cavitation (low pressure bubbles suddenly made in liquids by mechanical forces) in the water pump. With this type system, it is more difficult for an air or steam pocket to be made in the cooling system.

Visual Inspection Of The Cooling System

The cause for increased engine temperature is generally because regular inspections of the cooling system were not made. Make a visual inspection of the cooling system before a test is made with test equipment.

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DO NOT loosen the filler cap or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

1. After the engine is cool, loosen the pressure cap and turn it to the first stop to let pressure out of the cooling system. Then remove the pressure cap.

2. Check coolant level in the cooling system.

3. Look for leaks in the system.

4. Look for bent radiator fins. Be sure that air flow through the radiator does not have a restriction.

5. Inspect the drive belts for the fan.

6. Check for damage to the fan blades.

7. Look for air or combustion gas in the cooling system.

8. Inspect the filler cap and the surface that seals the cap. This surface must be clean and the seal must not be damaged.

Testing The Cooling System

Remember that temperature and pressure work together. When a diagnosis is made of a cooling system problem, temperature and pressure must both be checked. Cooling system pressure will have an effect on cooling system temperatures. For an example, look at the chart to see the effect of pressure and height above sea level on the boiling (steam) point of water.

Tests Tools for Cooling System

The 8T0470 Thermistor Thermometer Group is used in the diagnosis of overheating (engine hotter than normal) or overcooling (engine cooler than normal) problems. This group can be used to check temperatures in several different parts of the cooling system. The testing procedure is in Special Instruction, Form No. SEHS8446.

8T0470 Thermistor Thermometer Group

The 8T2700 Blowby/Air Flow Indicator Group is used to check the air flow through the radiator core. The operating instructions are included with the group.

8T2700 Blowby/Air Flow Indicator Group

The 6V3121 Multitach Group is used to check the fan speed. The testing procedure is in Special Instruction, Form No. SEHS7807.

6V3121 Multitach Group

Checking Pressure Cap

One cause for a pressure loss in the cooling system can be a bad seal on the radiator pressure cap.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

After the engine is cool, loosen the pressure cap and let the pressure out of the cooling system. Then remove the pressure cap.

Typical Schematic Of Pressure Cap
(A) Sealing surface of cap and radiator.

Inspect the pressure cap carefully. Look for damage to the seal or to the surface that seals. Any foreign material or deposits on the cap, seal or surface that seals, must be removed.

The 9S8140 Cooling System Pressurizing Pump Group is used to test pressure caps and to pressure check the cooling system for leaks.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

1. After the engine is cool, loosen the pressure cap to the first stop and let the pressure out of the cooling system. Then remove the pressure cap.

2. Put the pressure cap on the 9S8140 Cooling System Pressurizing Pump Group.

9S8140 Cooling System Pressurizing Pump Group
(1) Release Valve. (2) Adapter. (3) Hose.

3. Look at the gauge for the exact pressure that makes the pressure cap open.

4. Make a comparison of the reading on the gauge with the correct pressure at which the pressure cap must open.

NOTE: The correct pressure that makes the pressure cap open is on the pressure cap and is also in the Specifications.

5. If the pressure cap is bad, install a new pressure cap.

Testing Radiator and Cooling System for Leaks

To test the radiator and cooling system for leaks, use the procedure that follows:

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DO NOT loosen the filler cap or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

1. After the engine is cool, loosen the pressure cap to the first stop and let the pressure out of the cooling system. Then remove the pressure cap.

2. Make sure the coolant is over the top of the radiator core.

3. Put the 9S8140 Cooling System Pressurizing Pump Group on the radiator.

4. Get the pressure reading on the gauge to 20 kPa (3 psi) more than the pressure on the pressure cap.

5. Check the radiator for outside leakage.

6. Check all connections and hoses for the cooling system for outside leakage.

7. If you do not see any outside leakage and the pressure reading on the gauge is still the same after 5 minutes, the radiator and cooling system does not have leakage. If the reading on the gauge goes down and you do not see any outside leakage, there is leakage on the inside of the cooling system. Make repairs as necessary.

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If a Pressure indication is shown on the gauge, to avoid personal injury push release valve (1) to release all pressure in the system before removal of hose (3) from the radiator.

Water Temperature Gauge Test

Test Location
(1) Plug (one on each side of engine).

Check the accuracy of the water temperature gauge if either of the conditions that follow are found:

1. The gauge reads normal, but the engine is too hot and a loss of coolant is found.

2. The gauge shows that the engine is hot, but no loss of coolant can be found.

Remove plug (1) [1/2" Std. Pipe Thread] and install the 8T0470 Thermistor Thermometer Group or the 2F7112 Thermometer and 6B5072 Bushing. A temperature gauge of known accuracy can also be used to make this check.

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Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.

Start the engine and run it until the temperature reaches the desired range according to the test thermometer. If necessary, put a cover over part of the radiator or cause a restriction of the coolant flow. The reading on the gauge for water temperature should agree with test thermometer within the tolerance range of the gauge.

Water Temperature Regulator Test

1. Remove the regulator from the engine.

NOTE: For certain temperature regulators that operate near or above boiling 100° C (212° F) a 50/50% water/glycol solution must be used to achieve the temperature required to activate the regulator. Refer to Specifications Form No. SENR4603, for the correct complete opening temperature for each regulator.

2. Heat water (water/glycol) in a pan until the desired temperature is reached. Move the water (water/glycol) around in the pan to make it all the same temperature.

3. Hang the regulator in the pan of water (water/glycol). The regulator must be below the surface of the water (water/glycol) and it must be away from the sides and bottom of the pan.

4. Keep the water (water/glycol) at the correct temperature for 10 minutes.

5. After ten minutes, remove the regulator and immediately measure the distance the regulator has opened. The distance must be a minimum of 9.53 mm (.375 in).

6. If the distance is less than 9.53 mm (.375 in) make a replacement of the regulator.

Belt Tension Chart

Basic Block

Piston Rings

The 4C4519 Piston Ring Groove Gauge is available for checking the top piston ring groove with straight sides. For instructions on the use of the gauge, see the Guideline For Reusable Parts, Pistons, Form No. SEBF8049.

Connecting Rod Bearings

The connecting rod bearings fit tightly in the bore in the rod. If bearing joints or backs are worn (fretted), check bore size. This can be an indication of wear because of a loose fit.

Connecting rod bearings are available with 0.63 mm (.025 in) and 1.27 mm (.050 in) smaller inside diameter than the original size bearings. These bearings are for crankshafts that have been ground (made smaller than original size).

Main Bearings

Main bearings are available with a larger outside diameter than the original size bearings. These bearings are for cylinder blocks that have had the bore for the main bearings "bored" (made larger than the original size). The size available is 0.63 mm (.025 in) larger outside diameter than the original size bearings.

Cylinder Block

The bore in the block for main bearings can be checked with the main bearing caps installed without bearings. Tighten the nuts that hold the caps to the torque shown in the Specifications section. Alignment error in the bores must not be more than 0.08 mm (.003 in). Special Instruction, Form No. SMHS7606 gives instructions for the use of 1P4000 Line Boring Tool Group for alignment of the main bearing bores. The 1P3537 Dial Bore Gauge Group can be used to check the size of the bores. Special Instruction, Form No. GMG00981 is with the group.

1P3537 Dial Bore Gauge Group

Projection Of Cylinder Liners

Check liner projection above the spacer plate as follows:

1. Make sure the top surface of the cylinder block, the liner bores, spacer plates and liner flanges are clean and dry.

2. Install a new gasket and spacer plate (5) on the cylinder block.

3. Install the cylinder liners in the cylinder block without seals or bands.

Measuring Liner Height Projection
(1) 3H0465 Plate. (2) Dial indicator. (3) 1P2402 Gauge Body. (4) S1575 Bolt. (5) Spacer plate. (6) 8B7548 Puller Assembly (Crossbar).

4. Hold the spacer plate and liner in position as follows:

a. Install four bolts (4) and washers around each cylinder liner as shown. Tighten the bolts evenly to a torque of 95 N·m (70 lb ft).

b. Install crossbar (6), plates (1) and the two 8F6123 Bolts. Be sure the crossbar is in position at the center of the liner and the liner surface is clean. Tighten the bolts evenly to a torque of 70 N·m (50 lb ft).

c. Check the distance from the bottom edge of crossbar (6) to the top edge of the spacer plate. The distance on each end of the crossbar must be the same.

5. Use 8T0455 Liner Projection Tool Group to measure liner projection.

6. To zero dial indicator (2), use the back of 1P5507 Gauge with dial indicator (2) mounted in 1P2402 Gauge Body (3).

7. Liner projection must be 0.059 to 0.199 mm (.0023 to .0078 in). Make the measurement t the outer flange of the liner, not the inner ring. The maximum difference between high and low measurements made at four places around each liner is 0.05 mm (.002 in).

NOTE: If liner projection changes from point to point around the liner, turn the liner to a new position within the bore. If still not within specifications, move liner to a different bore.

NOTE: When liner projection is correct, put a temporary mark on the liner and spacer plate so when the seals and band are installed, the liner can be installed in the correct position.

Flywheel And Flywheel Housing

Face Run Out (axial eccentricity) of the Flywheel Housing

8T5096 Dial Indicator Group Installed

If any method other than given here is used, always remember bearing clearance must be removed to get correct measurements.

1. Fasten a dial indicator to the flywheel so the anvil of the indicator will touch the face of the flywheel housing.

2. Put a force on the crankshaft toward the rear before the indicator is read at each point.

Checking Face Runout Of The Flywheel Housing

3. With dial indicator set at "0" (zero) at location (A), turn the flywheel and read the indicator at locations (B), (C) and (D).

4. The difference between lower and higher measurements taken at all four points must not be more than 0.38 mm (.015 in), which is the maximum permissible face run out (axial eccentricity) of the flywheel housing.

Bore Runout (radial eccentricity) of the Flywheel Housing

1. Fasten the dial indicator as shown so the anvil of the indicator will touch the bore of the flywheel housing.

2. With the dial indicator in position at (C), adjust the dial indicator to "0" (zero). Push the crankshaft up against the top of the bearing. Write the measurement for bearing clearance on line 1 in column (C) in the Chart For Dial Indicator Measurements.

8T5096 Dial Indicator Group Installed

NOTE: Write the dial indicator measurements with their positive (+) and negative (-) notation (signs). This notation is necessary for making the calculations in the chart correctly.

3. Divide the measurement from Step 2 by 2. Write this number on line 1 in columns (B) & (D).

4. Turn the flywheel to put the dial indicator at (A). Adjust the dial indicator to "0" (zero).

5. Turn the flywheel counterclockwise to put the dial indicator at (B). Write the measurements in the chart.

Checking Bore Runout Of The Flywheel Housing

6. Turn the flywheel counterclockwise to put the dial indicator at (C). Write the measurement in the chart.

7. Turn the flywheel counterclockwise to put the dial indicator at (D). Write the measurement in the chart.

8. Add lines I & II by columns.

9. Subtract the smaller number from the larger number in line III in columns (B) & (D). The result is the horizontal eccentricity (out of round). Line III, column (C) is the vertical eccentricity.

10. On the graph for total eccentricity, find the point of intersection of the lines for vertical eccentricity and horizontal eccentricity.

11. If the point of intersection is in the range marked "Acceptable", the bore is in alignment. If the point of intersection is in the range marked "Not Acceptable", the flywheel housing must be changed.

Graph For Total Eccentricity

Face Runout (axial eccentricity) of the Flywheel.

1. Install the dial indicator as shown. Always put a force on the crankshaft in the same direction before the indicator is read so the crankshaft end clearance (movement) is always removed.

Checking Face Runout Of The Flywheel

2. Set the dial indicator to read "0" (zero).

3. Turn the flywheel and read the indicator every 90°.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.15 mm (.006 in), which is the maximum permissible face runout (axial eccentricity) of the flywheel.

Bore Runout (radial eccentricity) of the Flywheel

1. Install the dial indicator (3) and make an adjustment of the universal attachment (4) so it makes contact as shown.

2. Set the dial indicator to read "0" (zero).

3. Turn the flywheel and read the indicator every 90°.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.15 mm (.006 in), which is the maximum permissible bore runout (radial eccentricity) of the flywheel.

5. Runout (eccentricity) of the bore for the pilot bearing for the flywheel clutch, must not exceed 0.13 mm (.005 in).

Checking Bore Runout Of The Flywheel
(1) 7H1945 Holding Rod. (2) 7H1645 Holding Rod. (3) 7H1942 Indicator. (4) 7H1940 Universal Attachment.

Checking Flywheel Clutch Pilot Bearing Bore

Checking Crankshaft Deflection (Bend)

The crankshaft can be deflected (bent) because the installation of the engine was not correct. If the engine mounting rails are not fastened correctly to the foundation mounting rails, the cylinder block can twist or bend and cause the crankshaft to deflect. This deflection can cause crankshaft and bearing failure.

The crankshaft deflection must be checked after the final installation of the engine. The check must be made with the engine cold and also with the engine at the temperature of normal operation. The procedure that follows can be used to check crankshaft deflection with the engine either cold or warm.

1. Remove an inspection cover from the cylinder block that will give access to the connecting rod journal of the crankshaft nearest to the center of the engine.

2. Turn the crankshaft in the direction of normal rotation until the center of the counterweights just go beyond the connecting rod.

Measuring Deflection Of The Crankshaft (Typical Example)
(1) Dial gauge. (2) Mounting face.

3. Install a Starrett Crankshaft Distortion Dial Gauge No. 696 with Starrett No. 696B Balancer Attachment between the counterweights as shown. Put dial gauge (1) within 6.4 mm (.25 in) of counterweight mounting surface (2). Turn the dial of the indicator to get alignment of the zero and the pointer. Turn the indicator on its end points until the pointer of the indicator will not move from zero.

4. Turn the crankshaft in the direction of normal rotation until the indicator almost makes contact with the connecting rod on the other side of the crankshaft.

NOTE: Do not let the indicator make contact with the connecting rod.

5. The dial indicator reading must not change more than 0.03 mm (.001 in) for the approximately 300 degrees of crankshaft rotation. Now turn the crankshaft in the opposite direction to the starting position. The dial indicator must now read zero. If the dial indicator does not read zero, do the procedure again.

If the dial indicator reads more than 0.03 mm (.001 in), the cylinder block is bent. Loosen the bolts that hold the engine mounting rails to the foundation mounting rails and adjust the shims to make the engine straight again. Also, check to see if the engine mounting bolts have enough clearance to let the engine have expansion as it gets hot.

Vibration Damper

Damage to or failure of the damper will increase vibrations and result in damage of the crankshaft.

If the damper is bent or damaged, or if the bolt holes in the damper are loose fitting, replace the damper. Replacement of the damper is also needed at the time of crankshaft failure.

Electrical System

Test Tools For Electrical System

Most of the tests of the electrical system can be done on the engine. The wiring insulation must be in good condition, the wire and cable connections must be clean and tight, and the battery must be fully charged. If the on-engine test shows a defect in a component, remove the component for more testing.

The service manual Testing And Adjusting Electrical Components, Form No. REG00636, has complete specifications and procedures for the components of the starting circuit and the charging circuit.

6V4930 Battery Load Tester

The 6V4930 Battery Load Tester is a portable unit in a metal case for use under field conditions and high temperatures. It can be used to load test all 6, 8 and 12V batteries. This tester has two heavy-duty load cables that can easily be fastened to the battery terminals, and a load adjustment knob on the front panel permits a current range up to a maximum of 700 amperes. The tester also has a thermometer to show when the safe operating temperature limit of the unit has been reached.

NOTE: Make reference to Special Instruction, Form No. SEHS8268 for more complete information for use of the 6V4930 Battery Loader Test.

8T0900 AC/DC Clamp-On Ammeter

The 8T0900 AC/DC Clamp-On Ammeter is a completely portable, self-contained instrument that allows electrical current measurements to be made without breaking the circuit or disturbing the insulation on conductors. A digital display is located on the ammeter for reading current directly in a range from 1 to 1200 amperes. If an optional 6V6014 Cable is connected between this ammeter and one of the digital multimeters, current readings of less than 1 ampere can then be read directly from the display of the multimeter.

A lever is used to open the jaws over the conductor [up to a diameter of 19 mm (.75 in)], and the spring loaded jaws are then closed around the conductor for current measurement. A trigger switch that can be locked in the ON or OFF position is used to turn on the ammeter. When the turn-on trigger is released, the last current reading is held on the display for 5 seconds. This allows accurate measurements to be taken in limited access areas where the digital display is not visible to the operator. A zero control is provided for DC operation, and power for the ammeter is supplied by batteries located inside the handle.

NOTE: Make reference to Special Instruction, Form No. SEHS8420 for more information for use of the 8T0900 Clamp-on Ammeter.

6V7070 Heavy-Duty Digital Multimeter

The 6V7070 Heavy-Duty Digital Multimeter is a completely portable, hand held instrument with a digital display. This multimeter is built with extra protection against damage in field applications, and is equipped with seven functions and 29 ranges. The 6V7070 Multimeter has an instant ohms indicator that permits continuity checking for fast circuit inspection. It also can be used for troubleshooting small value capacitors.

The 6V7800 Regular-Duty Digital Multimeter (a low cost option to the Heavy-Duty Multimeter) is also available; however, the 6V7800 Multimeter does not have the 10A range or the instant ohms feature of the 6V7070 Multimeter.

NOTE: Make reference to Special Instruction, Form No. SEHS7734 for more complete information for use of the 6V7070 and 6V7800 Multimeters.

Battery

Show/hide table

Never disconnect any charging unit circuit or battery circuit cable from battery when the charging unit is operated. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Injury to personnel can be the result.

The battery circuit is an electrical load on the charging unit. The load is variable because of the condition of the charge in the battery. Damage to the charging unit will result if the connections (either positive or negative) between the battery and charging unit are broken while the charging unit is in operation. This is because the battery load is lost and there is an increase in charging voltage. High voltage will damage, not only the charging unit, but also the regulator and other electrical components.

Use the 6V4930 Battery Load Tester, the 8T0900 Clamp-On Ammeter and the 6V7070 Multimeter to load test a battery that does not hold a charge when in use. See Special Instruction, Form No. SEHS8268 for the correct procedure and specifications to use.

Charging System

The condition of charge in the battery at each regular inspection will show if the charging system operates correctly. An adjustment is necessary when the battery is constantly in a low condition of charge or a large amount of water is needed (more than one ounce of water per cell per week or per every 100 service hours).

When it is possible, make a test of the charging unit and voltage regulator on the engine, and use wiring and components that are a permanent part of the system. Off-engine (bench) testing will give a test of the charging unit and voltage regulator operation. This testing will give an indication of needed repair. After repairs are made, again make a test to give proof that the units are repaired to their original condition of operation.

Before the start of on-engine testing, the charging system and battery must be checked as shown in the Steps that follow:

1. Battery must be at least 75% (1.225 Sp. Gr.) fully charged and held tightly in place. The battery holder must not put too much stress on the battery.

2. Cables between the battery, starter and engine ground must be the correct size. Wires and cables must be free of corrosion and have cable support clamps to prevent stress on battery connections (terminals).

3. Leads, junctions, switches and panel instruments that have direct relation to the charging circuit must give correct circuit control.

4. Inspect the drive components for the charging unit to be sure they are free of grease and oil and have the ability to operate the charging unit.

Regulator

The voltage regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system, and switches on and off many times a second to control the field current (DC current to the field windings) to the alternator. The output voltage from the alternator will now supply the needs of the battery and the other components in the electrical system.

When an alternator is charging the battery too much or not enough, check for correct drive belt tension and inspect all cables and connections. No adjustment can be made to change the rate of charge on these alternator regulators. If rate of charge is not correct, a replacement of the regulator is necessary. Make reference to the Specifications section to find all testing and specifications for the alternators and regulators.

Alternator Pulley Nut Tightening (Delco-Remy)

Tighten nut that holds the pulley to a torque of 95 to 110 N·m (70 to 80 lb ft) with the tools shown.

Tools To Tighten Alternator Pulley Nut
(1) 6V7916 Torque Wrench. (2) 8S1588 Adapter (1/2" female to 3/8" male). (3) FT1697 Socket. (4) 8H8517 Combination Wrench (1 1/8"). (5) FT1696 Wrench.

Starting System

Use the multimeter in the DCV range to find starting system components which do not function.

Move the start control switch to activate the starter solenoid. Starter solenoid operation can be heard as the pinion of the starter motor is engaged with the ring gear on the engine flywheel.

If the solenoid for the starter motor will not operate, it is possible that the current from the battery did not get to the solenoid. Fasten one lead of the multimeter to the connection (terminal) for the battery cable on the solenoid. Put the other lead to a good ground. A zero reading is an indication that there is a broken circuit from the battery. More testing is necessary when there is a voltage reading on the Multimeter.

The solenoid operation also closes the electric circuit to the motor. Connect one lead of the multimeter to the solenoid connection (terminal) that is fastened to the motor. Put the other lead to a good ground. Activate the starter solenoid and look at the multimeter. A reading of battery voltage shows the problem is in the motor. The motor must be removed for further testing. A zero reading on the multimeter shows that the solenoid contacts do not close. This is an indication of the need for repair to the solenoid or an adjustment to be made to the starter pinion clearance.

Make a test with one multimeter lead fastened to the connection (terminal) for the small wire at the solenoid and the other lead to the ground. Look at the Multimeter and activate the starter solenoid. A voltage reading shows that the problem is in the solenoid. A zero reading is an indication that the problem is in the start switch or the wires for the start switch.

Fasten one multimeter lead to the start switch at the connection (terminal) for the wire from the battery. Fasten the other lead to a good ground. A zero reading indicates a broken circuit from the battery. Make a check of the circuit breaker and wiring. If there is a voltage reading, the problem is in the start switch or in the wires for the start switch.

A starter motor that operates too slow can have an overload because of too much friction in the engine being started. Slow operation of the starter motor can also be caused by a short circuit, loose connections and/or dirt in the motor.

Pinion Clearance Adjustment (Delco-Remy)

When the solenoid is installed, make an adjustment of the pinion clearance. The adjustment can be made with the starter motor removed.

Connection For Checking Pinion Clearance
(1) Connector from MOTOR terminal on solenoid to motor. (2) SW terminal. (3) Ground terminal.

1. Install the solenoid without connector (1) from the MOTOR connections (terminal) on solenoid to the motor.

2. Connect a battery, of the same voltage as the solenoid, to the terminal (2), marked SW.

3. Connect the other side of the battery to ground terminal (3).

4. Connect for a moment, a wire from the solenoid connection (terminal) marked MOTOR to the ground connection (terminal). The pinion will shift to crank position and will stay there until the battery is disconnected.

Pinion Clearance Adjustment
(4) Shaft nut. (5) Pinion. (6) Pinion clearance.

5. Push the pinion toward the commutator end to remove free movement.

6. Pinion clearance (6) must be 8.3 to 9.9 mm (.33 to .39 in).

7. To adjust pinion clearance, remove plug and turn nut (4).

Solenoid Position Adjustment (Bosch)

The solenoid position on the starting motor controls pinion clearance. If the solenoid position dimension is correct, the pinion clearance is correct. Do the following procedure to adjust the solenoid position.

Solenoid Position Measurement

1. Check distance (X) between intermediate housing (1) and solenoid mounting bracket (2) with calipers.

Solenoid Assembly
(1) Intermediate housing. (2) Solenoid mounting bracket. (3) Bolts (X) 62.5 + 0.2 - 0.5 mm (2.46 + .008 - .020 in).

2. If distance (X) is not correct, loosen bolts (3) and move the solenoid until distance (X) is correct. Bracket (2) has elongated holes.

3. Tighten bolts (3) after the adjustment is correct, to a torque of 7 to 10 N·m (5 to 7 lb ft).

Air Starting System

Pressure Regulating Valve

Pressure Regulating Valve (Typical Illustration)
(1) Adjustment screw. (2) Regulator inlet. (3) Regulator outlet.

To check and adjust the pressure regulating valve, use the procedure that follows:

1. Drain the line to the pressure regulating valve or drain the air storage tank.

2. Disconnect the regulator from the starter control valve.

3. Connect an 8M2885 Pressure Gauge to regulator outlet (3).

4. Put air pressure in the line or tank.

5. Check the pressure.

6. Adjust the pressure regulating valve as shown in Chart For Air Pressure Setting.

7. Remove the air pressure from the line or tank.

8. Remove the 8M2885 Pressure Gauge and connect the air pressure regulator to the line to the air starter motor.

Each engine application will have to be inspected to get the most acceptable starting results. Some of the factors that affect regulating valve pressure setting are: attachment loads pulled by engine during starting, ambient temperature conditions, oil viscosity, capacity of air reservoir, and condition of engine (new or worn).

The advantage of setting the valve at the higher pressures is increased torque for starter motor and faster rotation of engine. The advantage of setting the valve at the lower pressures is longer time of engine rotation for a given reservoir capacity of supply air.

Lubrication

Always use an air line lubricator with these air starter motors.

For temperatures above 0°C (32°F), use a good quality SAE 10 motor oil.

For temperatures below 0°C (32°F), use diesel fuel.

To maintain the efficiency of the starter motor, flush it at regular intervals. Pour approximately 0.5 liter (1 pt) of diesel fuel into the air inlet of the starter motor and operate the motor. This will remove the dirt, water and oil mixture (gummy coating) from the vanes of the motor.