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 can not give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.

Troubleshooting Index

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

2a. Engine Will Not Start. Governor Terminal Shaft Does Not Move.

2b. Engine Will Not Start. Governor Terminal Shaft Moves.

3. Engine Overspeeds On Start.

4. Engine Speed Does Not Have Stability.

5. Engine High Idle Speed Too Low.

6. Engine Can Not Be Shut Down Through Governor.

7. Engine Misfiring or Running Rough.

8. Engine Stall at Low rpm.

9. Not Enough Power.

10. Too Much Vibration.

11. Loud Combustion Noise.

12. Valve Train Noise (Clicking).

13. Oil In Cooling System.

14. Mechanical Noise (Knock) In Engine.

15. Fuel Consumption Too High

16. Loud Valve Train Noise.

17. Too Much Valve Lash.

18. Valve Rotocoil or Spring Lock is Free.

19. Oil at the Exhaust.

20. Little or No Valve Clearance.

21. Engine Has Early Wear.

22. Coolant in Lubrication Oil.

23. Too Much Black or Gray Smoke.

24. Too Much White or Blue Smoke.

25. Engine Has Low Oil Pressure.

26. Engine Uses Too Much Lubrication Oil.

27. Engine Coolant Is Too Hot.

28. Starter Motor Does Not Turn.

29. Alternator Gives No Charge.

30. Alternator Charge Rate Is Low or Not Regular.

31. Alternator Charge Too High.

32. Alternator Has Noise.

33. Exhaust Temperature Too High.

34. Air Starting Motor Turns Slowly or Has A Loss of Power.

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

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

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

Engine Crankshaft Will Not Turn When Start Switch Is On

Engine Will Not Start - Governor Terminal Shaft Does Not Move Fuel Control Linkage

Engine Will Not Start - Governor Terminal Shaft Opens At Least Half Way Or More At Cranking As Observed By Outboard Shaft Rotation

Engine Overspeeds On Start

Engine Speed Does Not Have Stability.

Engine High Idle Speed Too Low

Engine Cannot Be Shut Down Through Governor.

Engine Misfiring Or Running Rough

Engine Stall At Low RPM

Not Enough Power

Too Much Vibration

Loud Combustion Noise (Sound)

Valve Train Noise (Clicking)

Oil In Cooling System

Mechanical Noise (Knock) In Engine

Fuel Consumption Too High

Loud Valve Train Noise

Too Much Valve Lash

Valve Rotocoil Or Spring Lock Is Free

Oil At The Exhaust

Little Or No Valve Clearance

Engine Has Early Wear

Coolant In Lubrication Oil

Too Much Black Or Gray Smoke

Too Much White Or Blue Smoke

Engine Has Low Oil Pressure

Engine Uses Too Much Lubrication Oil

Engine Coolant Is Too Hot

Starter Motor Does Not Turn

Alternator Gives No Charge

Alternator Charge Rate Is Low Or Not Regular

Alternator Charge Too High

Alternator Has Noise

Exhaust Temperature Is Too High

Air Starting Motor Turns Slowly Or Has A Loss Of Power

Air Starting Motor Pinion Does Not Engage With The Flywheel

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

Air Starting Motor Pinion Does Not Engage Correctly With The Flywheel

Fuel System

Either too much fuel or not enough fuel for combustion can be the cause of a problem in the fuel system.

Many times work is done on the fuel system when the problem is really with some other part of the engine. The source of the problem is difficult to find, especially when smoke comes from the exhaust. Smoke that comes from the exhaust can be caused by a bad fuel injector, but it can also be caused by one or more of the reasons that follow:

a. Not enough air for good combustion.

b. An overload at high altitude.

c. Oil leakage into combustion chamber.

d. Not enough compression.

Fuel System Inspection

A problem with the components that send fuel to the engine can cause low fuel pressure. This can decrease engine performance.

1. Check the fuel level in the fuel tank. Look at the cap for the fuel tank to make sure the vent is not filled with dirt.

2. Check the fuel lines for fuel leakage. Be sure the fuel supply line does not have a restriction or a bad bend.

3. Install new fuel filters. Clean the primary fuel filter.

4. Inspect the fuel pressure relief valve in the fuel transfer pump to see that there is no restriction to good operation.

Checking Engine Cylinders Separately

Temperature of an exhaust manifold port, when the engine runs at low idle speed, can be an indication of the condition of a fuel injector. Low temperature at an exhaust manifold port is an indication of no fuel to the cylinder. This can possibly be an indication of an injector with a defect. Extra high temperature at an exhaust manifold port can be an indication of too much fuel to the cylinder, also cased by an injector with a defect.

Fuel Pressure

The 6V9450 Engine Pressure Group can be used to check engine fuel pressures.

6V9450 ENGINE PRESSURE GROUP

This tool group has a gauge to read pressure in the fuel manifolds. Special Instruction Form No. SEHS8524 is with the tool group and gives information for its use.

FUEL MANIFOLD AND LINES
6. Fuel supply line to cylinder head. 7. Fuel manifold.

The fuel pressure regulating valve keeps the pressure in fuel manifolds (7) between 415 and 450 kPa (60 to 65 psi). To check the fuel manifold pressure, disconnect one of the fuel lines (6) and install a tee between the line and manifold. Connect the 6V9450 Engine Pressure Group to the tee and operate the engine.

Engine Rotation

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

Finding Top Center Position For No. 1 Piston

9S9082 Engine Turning Tool.

TIMING BOLT LOCATION
1. Cover. 2. Timing bolt. 3. Plug in timing bolt hole.

1. Remove cover (1) and the timing hole plug (3) from the right front side of the flywheel housing.

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 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
2. Timing bolt. 4. 9S9082 Engine Turning 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 can not be moved and the valves are slightly open, the No. 1 piston is on the exhaust stroke. Make reference to charts for CRANKSHAFT POSITIONS FOR INJECTOR TIMING AND VALVE CLEARANCE SETTING to find the correct cylinder(s) to be checked/adjusted for the stroke position of the crankshaft when the timing bolt has been 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 (3512 SHOWN)

Camshaft Timing

Timing Check

9S9082 Engine Turning Tool.

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

LOCATION OF TIMING PINS
1. Timing hole. 2. Timing pin. 3. Cover.

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, 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.

INSTALLATION OF TIMING PINS
2. Timing pin. 4. Camshaft (R.H.).

4. With timing bolt installed in flywheel with No. 1 piston now 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.

7. 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

9S9082 Engine Turning Tool.6V3010 Puller Group.8S9089 Two 1/2 - 13 NC Bolts 114.3 mm (4.50 in.) long.5P1076 Two Washers (Hardened).

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.

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 injectors and the valves.

NOTE: The above procedure must be done before camshaft drive gear (5) is pulled off the camshaft taper.

LOOSEN ROCKER SHAFTS
1. Bolt. 2. Rocker shaft.

2. If LH flywheel cover is to be removed, first remove tachometer drive and service meter as a unit. Now remove the tachometer drive shaft.

3. Remove the cover(s) from the flywheel housing. Remove tachometer drive adapter (4) from LH side and/or plate (6) from opposite side.

REMOVE CAMSHAFT DRIVE GEARS (LH SIDE)
3. Bolt. 4. Tachometer drive adapter. 5. Drive gear.

CAMSHAFT DRIVE GEARS (RH SIDE)
5. Drive gear. 6. Plate.

4. Install the 6V3070 Puller Group, two 8S9089 Bolts and two 5P1076 Washers. Loosen drive gears (5) from the taper on the camshafts. Remove the tooling and the gears.

5. Remove timing pin(s) (7) from the storage position (under the rear camshaft covers) on each side of the engine.

CAMSHAFT TIMING PIN INSTALLED
7. Timing pin.

6. Turn camshafts and install timing pins (7) through the engine block and into the groove (slot) in the camshaft on each side of the engine.

INSTALL CAMSHAFT DRIVE GEARS
4. Tachometer drive adapter. 5. Drive gear. 9. Tachometer drive shaft.

7. Install camshaft drive gears as follows:

a. Put camshaft drive gears (5) in position on the camshaft taper.

b. For correct timing, all gear clearance (backlash) must be removed. Turn camshaft drive gears (5) in the same direction as crankshaft rotation and hold in this position.

c. Install tachometer drive adapter (4) on the left side and plate (6) on the right side to hold camshaft drive gears (5) to the camshafts. Tighten the bolts with the procedure that follows:

d. For gears with two bolts, tighten the bolts in steps to a torque of 100 ± 15 N·m (75 ± 11 lb. ft.). For gears with one bolt, tighten the bolt in steps to a torque of 360 ± 50 N·m (265 ± 35 lb. ft.).

e. Hit the face of plate (6) and tachometer drive adapter (4). Tighten the bolts again to a torque of 100 ± 15 N·m (75 ± 11 lb. ft.) or 360 ± 50 N·m (265 ± 35 lb. ft.).

f. Again hit the face of the plate and tachometer drive adapter, and again tighten the bolts to a torque of 100 ± 15 N·m (75 ± 11 lb.ft.) or 360 ± 50 N·m (265 ± 35 lb. ft.).

NOTE: If necessary, do Step 7f until the bolts hold torque (can not be moved) to make sure the drive gears are in full contact with the taper on the camshafts.

8. Install tachometer drive shaft (9) in tachometer drive adapter (4). Install covers and gaskets on flywheel housing. Install tachometer drive and service meter on LH cover.

STORAGE POSITION FOR TIMING PINS
7. Timing pin. 8. Cover.

9. Remove timing pins (7) from the camshafts. Install timing pins (7) in their storage positions. Install covers (8) over the camshafts and timing pins.

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

11. Make sure the rocker arms are engaged correctly with the push rods, and tighten the bolts to hold all of the rocker shafts in position.

12. Make adjustments to the valves and fuel timing. See VALVE CLEARANCE SETTING and FUEL TIMING for the correct procedures.

Start Up Procedure

Use this procedure when an engine is started for the first time after work is done on the fuel system or governor.

1. Disconnect the air inlet system from the turbochargers.

2. Have a person in position near each turbocharger air inlet with a piece of steel plate large enough to completely cover the turbocharger air inlet.

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Be careful when plate is put against air inlet opening. Due to excessive suction, the plate can be pulled quickly against air inlet openings. To avoid crushed fingers, do not put fingers between plate and air inlet opening.

3. Start the engine. If the engine starts to run too fast or runs out of control, immediately put the steel plates against the turbocharger air inlets. This will stop the air supply to the engine, and the engine will stop.

Crankshaft Positions For Fuel Timing And Valve Clearance Setting

CYLINDER AND VALVE LOCATION (3512 SHOWN)

Fuel Timing

6V7880 Timing and Fuel Setting Tool Group.8S3675 Contact Point, 3.0 mm (.12 in.) long.6V3075 Dial Indicator (Metric).6V3117 Set Gauge.6V7881 Timing Fixture.9S9082 Engine Turning Tool.

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NOTICE
The camshafts must be correctly timed with the crankshaft before an adjustment of fuel timing is made. The timing pins must be removed from the camshafts before the crankshaft is turned or damage to the cylinder block will be the result.

1. See chart CRANKSHAFT POSITIONS FOR FUEL TIMING AND VALVE CLEARANCE SETTING and put the engine in time. With the two crankshaft positions given in the chart, all of the injectors can be checked or adjusted. This will make sure the pushrod lifters are off the lobes and on the base circles of the camshafts.

NOTE: See the Fuel Setting And Related Information Fiche for the correct fuel timing dimension to use.

Before a check or an adjustment of the fuel timing can be made, the tooling must be set to the correct dimension as follows:

FUEL TIMING TOOLS
1. 6V3117 Set Gauge. 2. 6V3075 Dial Indicator (metric). 3. 8S3675 Contact Point, 3.0 mm (.12 in.) long. 4. 6V7881 Timing Fixture.

2. Install the 8S3675 Contact Point on the dial indicator stem.

3. Install 6V3075 Dial Indicator (2) in the collet of 6V7881 Timing Fixture (4).

ADJUSTMENT OF FUEL TIMING TOOLS

4. Put the dial indicator and timing fixture on 6V3117 Set Gauge (1) with the angle of the timing fixture on the top surface and the extension rod on the bottom step.

5. Move the dial indicator in the collet until the pointers indicate zero. Now move the dial indicator in the collet until the large pointer indicates setting shown in the DIAL INDICATOR SETTING CHART (if other than zero setting) and tighten the collet.

6. Make sure the top surfaces of injector follower (5) and shoulder (6) are clean and dry.

7. Put 6V3075 Dial Indicator (2) and 6V7881 Timing Fixture (4) in position on the injector to be checked. Make sure the angle of the timing fixture is on the top surface of follower (5) and the extension rod is on the top surface of injector shoulder (6) as shown in illustration.

FUEL TIMING TOOLS IN POSITION
2. 6V3075 Dial Indicator (metric). 4. 6V7881 Timing Fixture. 5. Injector follower. 6. Shoulder on injector body.

8. The dial indicator pointers must indicate 0.00 ± 0.20 mm.

9. If the dial indicator pointers indicate zero, or are within the tolerance given in Step 8, no adjustment is necessary. Proceed to Step 14.

10. If the dial indicator pointers do not indicate 0.00 ± 0.20 mm, do Steps 11 through 14.

11. Loosen the push rod adjustment screw locknut for the injector to be adjusted.

12. Put 6V3075 Dial Indicator (2) and 6V7881 Timing Fixture (4) in position on the injector to be adjusted. Make sure that the timing fixture sets flat on the top surface of follower (5), and the extension rod is on the top surface of injector shoulder (6).

FUEL TIMING TOOLS IN POSITION

13. Turn the adjustment screw until zero is read on the dial indicator. Tighten the adjustment screw locknut to a torque of 70 ± 15 N·m (50 ± 11 lb. ft.) and check adjustment again. If necessary, do this procedure again until the adjustment is correct.

ADJUSTMENT OF FUEL TIMING

14. Remove the timing bolt from the flywheel when the fuel timing check is completed.

Injector Synchronization

8T2684 Rack Synchronizing Gauge.

Injector synchronization is the setting of all injector racks to a reference position so each injector gives the same amount of fuel to each cylinder. This is done by setting each injector rack to the same position while the control linkage is in a fixed position (called the synchronizing position). The procedure for adjustment of injector synchronization is as follows:

LOCATION OF FUEL SETTING COVER AND SYNCHRONIZING PIN
1. Plug. 2. Synchronizing pin. 3. Cover.

1. The top bolt that holds cover (3) in position is synchronizing pin (2). Remove synchronizing pin (2) and plug (1) from the front drive housing. DO NOT destroy seal or remove cover (3).

2. Remove the washer from synchronizing pin (2) and install it into the threaded hole where plug (1) was removed. Tighten synchronizing pin (2).

SYNCHRONIZING POSITION (Governor Fastener Cover Removed Only For Illustration)
2. Synchronizing pin. 4. Fuel stop lever.

LOCATION FOR GAUGE AND CONTROL ROD ADJUSTMENT (Rocker Shaft Removed for Illustration)
5. 8T2684 Rack Synchronizing Gauge [12.7 mm (.50 in.)]. 6. Control rod.

3. Turn the governor or actuator terminal shaft to the fuel "ON" position until the flat face of fuel stop lever (4) contacts synchronizing pin (2). This is the synchronizing position or zero reference point. Hold the control linkage in this position when the injectors are adjusted.

4. Remove the valve covers.

5. With the fuel stop lever against the synchronizing pin, put 8T2684 Rack Synchronizing Gauge (5) on the round part of the injector rack between the injector body and the end of the rack. Use a screwdriver and make an adjustment of control rod (6). Turn the screw on control rod (6) one "click" at a time until rack synchronizing gauge (5) just fits between the injector body and the shoulder at the end of the rack. Remove the screwdriver from control rod (6) so no pressure is on the linkage while the setting is checked with rack synchronizing gauge (5). Any pressure on the linkage with the screwdriver will not give a correct indication when the setting is checked with the rack synchronizing gauge. To make sure the linkage is free and giving the correct setting, move (flip) the linkage and check the setting again. Put the box end of a 9/16" or 5/8" combination wrench over the nut and bolt that holds control rod (6) and the bellcrank together. Pull up on the control rod two or three times; then check the setting again.

GAUGE IN POSITION ON INJECTOR RACK (Rocker Shaft Removed for Illustration)
5. 8T2684 Rack Synchronizing Gauge [12.7 mm (.50 in.)]. 7. Fuel injector rack.

ADJUSTMENT OF FUEL CONTROL ROD
5. 6V3119 Rack Synchronizing Gauge.

6. Use rack synchronizing gauge (5) and, if necessary, make the adjustment to the other injectors. When all adjustments have been made, release the actuator terminal shaft.

7. Install the valve covers.

8. Make a check of the fuel setting and make adjustments if necessary. See FUEL SETTING for this procedure.

Fuel Setting

6V7880 Timing and Fuel Setting Tool Group.5P4814 Collet.6V3075 Dial Indicator (metric).5P7263 Contact Point, 76.2 mm (3.00 in.) long.8T2684 Rack Synchronizing Gauge 12.7 mm (.50 in.).

Fuel Setting Check

Fuel setting is the adjustment of the fuel setting screw to a specified position. The fuel setting screw limits the power output of the engine by setting the maximum travel of all the injector racks.

SYNCHRONIZATION AND FUEL SETTING TOOLS
1. 8T2684 Rack Synchronizing Gauge. 2. 6V3075 Dial Indicator (metric). 3. 5P4814 Collet. 4. 5P7263 Contact Point, 76.2 mm (3.00 in.) long.

Before the fuel setting is checked, the injectors must be correctly synchronized. See the subject INJECTOR SYNCHRONIZATION. After the injectors are synchronized correctly, leave the synchronizing pin in place for the procedure that follows.

1. Put 6V3075 Dial Indicator (2) with 5P7263 Contact Point (4) in 5P4814 Collet (3). Remove the plug from the right side of fuel setting cover (8).

INSTALL DIAL INDICATOR
2. 6V3075 Dial Indicator with 5P7263 Contact Point attached. 3. 5P4814 Collet.

2. Move the governor or actuator terminal shaft in the fuel "ON" direction until the flat face of fuel stop lever (6) contacts synchronizing pin (5). Hold the linkage in this position.

DIAL INDICATOR IN POSITION (Cover Removed Only for Photo Illustration)
2. 6V3075 Dial Indicator. 4. 5P7263 Contact Point, 76.2 mm (3.00 in.) long. 5. Synchronizing pin. 6. Fuel stop lever.

3. Install the dial indicator and collet (3) in the threaded hole as shown. When the contact point seats against fuel stop lever (6), slide the dial indicator in or out until the indicator reads zero. Now tighten collet (3) just enough to hold indicator at this position.

CHECKING FUEL SETTING
2. 6V3075 Dial Indicator (metric). 5. Synchronizing pin. 8. Fuel setting cover.

4. Turn synchronizing pin (5) back out a minimum of 25 mm (1 in.) (or remove it completely), and then slowly move the governor or actuator terminal shaft in the fuel "ON" direction until the flat face of the fuel stop lever is against the end of the fuel setting screw. With the linkage held in this position, the dial indicator reading will be the present fuel setting.

NOTE: See FUEL SETTING AND RELATED INFORMATION FICHE for the correct fuel setting.

5. If fuel setting is correct, remove the dial indicator and synchronizing pin (5). Install the two plugs, and install pin (5) back into cover (8).

6. If fuel setting needs adjustment, go on to Fuel Setting Adjustment.

Fuel Setting Adjustment

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NOTICE
A mechanic with governor and fuel setting training is the ONLY one to make adjustments to the engine fuel setting.

1. Cut the seal wire and remove fuel setting cover (8) and the gasket. Loosen locknut (7) and (with fuel stop lever still held against end of the fuel setting screw) turn the fuel setting screw in or out until the correct reading is on the dial indicator.

ADJUSTMENT OF THE FUEL SETTING SCREW

2. Now tighten locknut (7). Be sure that the fuel setting screw does not turn when the locknut (7) is tightened. Release the fuel linkage and again move linkage all the way in the fuel "ON" direction. Check the dial indicator reading again to be sure that fuel setting is still correct.

3. Remove the dial indicator and synchronizing pin (5), then install the two plugs.

INSTALL COVER
7. Locknut. 8. Fuel setting cover.

4. Put fuel setting cover (8) and gasket in position over the fuel setting screw and install bolt and synchronizing pin (5) in cover. Install a new seal wire.

Engine Speed Measurement

6V3121 MULTITACH GROUP

The 6V3121 Multitach Group can measure engine speed from a tachometer drive on the engine. It also has the ability to measure engine speed from visual engine parts in rotation.

Special Instruction, Form No. SEHS7807 is with the 6V3121 Multitach Group and gives instructions for the test procedure.

Woodward UG8 Lever Governor

Compensating Adjustment

Although the governor may appear to be operating satisfactorily at no load, high overspeeds and underspeeds after load changes and slow return to normal speed are the results of incorrect compensation adjustments.

After the temperature of the engine and the oil in the governor have reached normal operating values, make compensation adjustments with the engine running at no load conditions.

UG8 LEVER GOVERNOR
1. Compensation pointer. 2. Plug.

1. Loosen the nut that holds compensation pointer (1) and move the pointer up as far as it will go. Tighten the nut.

2. Remove plug (2) from the base of the governor to get access to the needle valve.

3. Use a screwdriver and turn the needle valve three to five turns in a counterclockwise (open) direction. Make sure the screwdriver engages with the shallow slot of the compensating needle valve and not in the deep slot that is at right angles to the shallow screwdriver slot.

4. Let the engine surge for approximately 30 seconds to help remove air from the governor oil passages.

5. Loosen the nut that holds compensation pointer (1) and move the pointer down as far as it will go. Tighten the nut.

6. Slowly turn the needle valve in a clockwise direction until the engine surge just stops.

7. Now check the number of turns the needle valve is open. To find the number of turns the needle valve is open, close the valve completely and make a note of the number of turns needed to close the valve.

8. Open the needle valve to the same position at which the engine did not surge (Step 6).

9. Move the governor linkage to change the engine speed. If the engine does not surge, and the needle valve is 1/2 to 3/4 of a turn open, the governor adjustment is correct. Install plug (2) in the base. If the needle valve is more than 3/4of a turn open, do the steps that follow.

10. Loosen the nut and move compensation pointer (1) up two marks on the pointer scale.

11. Turn the needle valve three to five turns in a counterclockwise (open) direction.

12. Let the engine surge for approximately 30 seconds to help remove air from the governor oil passages.

13. Slowly turn the needle valve in a clockwise direction until the engine surge just stops.

14. Now check the number of turns the needle valve is open. To find the number of turns the needle valve is open, close the valve completely and make a note of the number of turns needed to close the valve.

15. Open the needle valve to the same position at which the engine did not surge (Step 13).

16. Move the governor linkage to change the engine speed. If the engine does not surge, and the needle valve is 1/2 to 3/4 of a turn open, the governor adjustment is correct. Install plug (2) in the base. If the needle valve is more than 3/4of a turn open, do Steps 10 thru 16 again.

A needle valve that is opened less than 1/2 turn will cause a slow return of the engine to normal speed after a load change.

If the compensation pointer is too far toward the maximum position, the engine speed change will be too great when the load changes.

Low And High Idle Speed Adjustment

Connect a tachometer with good accuracy to the engine. Make reference to MEASURING ENGINE SPEED.

1. Start the engine and run to get the engine to the normal temperature of operation.

LOW AND HIGH IDLE ADJUSTMENT
1. Low idle adjustment screw. 2. Locknut. 3. Locknut. 4. High idle adjustment screw. 5. Governor speed adjustment shaft.

2. Move the governor speed adjusting shaft (5) to run the engine at high idle speed. Loosen locknut (3) and turn high idle adjustment screw (4). Turn adjustment screw (4) clockwise to decrease engine speed and counterclockwise to increase engine speed.

3. After the high idle speed has been adjusted, tighten the locknut and check high idle speed again.

NOTE: Make reference to the Fuel Setting and Related Information Fiche for the correct low and high idle speed.

4. Move the governor speed adjusting shaft (5) to run the engine at low idle speed. Loosen locknut (2) and turn low idle adjustment screw (1). Turn adjustment screw (1) clockwise to increase low idle speed and counterclockwise to decrease low idle speed.

LOW AND HIGH IDLE STOP LEVER
6. Low and high idle stop lever.

Speed Droop Adjustment

Adjustment for Zero Droop

8T5096 Dial Indicator Group.6V6042 Indicator Contact Point Group.

1. Disconnect the engine oil pressure and air inlet pressure lines for the fuel ratio control housing.

COVER AND SHUT-OFF SOLENOID
1. Cover assembly.

2. Remove the oil level gauge from cover assembly (1).

3. Remove the screws that hold cover assembly (1) in position. Remove cover assembly (1) and the shut-off actuator as a unit from the governor.

OIL PRESSURE LINE TO FUEL RATIO CONTROL
2. Junction block. 3. Oil pressure line (from rotating bushing).

4. Remove the screw and pull junction block (2) from oil pressure line (3).

REMOVAL OF FUEL RATIO CONTROL
3. Oil pressure line. 4. Fuel ratio control housing. 5. Lever. 6. Shut-off strap.

5. Remove the eight bolts that hold fuel ratio control housing (4) to the governor housing. Lift the unit until lever (5) is disconnected from the compensation lever. Turn and lift the unit to move the fuel ratio control around and off shut-off strap (6). Be careful not to damage pressure line (3) when the fuel ratio control is removed.

GOVERNOR SHUT-OFF STRAP
6. Shut-off strap.

6. Move shut-off strap (6) off the pins in the governor housing and remove it.

DROOP ADJUSTMENT
7. Speeder plug. 8. Droop cam. 9. Screw. 10. Bracket. 11. Terminal shaft.

7. Install the 3S3269 Contact Point, 25.4 mm (1.00 in.) long on the dial indicator. Put the dial indicator in position on the governor with the contact point on bracket (10) of speeder plug (7). Adjust the dial of the indicator to zero.

DROOP ADJUSTMENT
10. Bracket.

8. Move governor terminal shaft (11) from the maximum position to the minimum position. The dial indicator must read 0.00 to 0.05 mm (.000 to .002 in.) for zero droop.

9. If the droop adjustment is not correct, loosen screw (9) and move droop cam (8). Tighten screw (9). Move droop cam (8) toward speeder plug (7) to increase droop, and away from the speeder plug to decrease droop.

10. Check the speed droop adjustment again with the dial indicator.

11. Install the shut-off strap in the governor.

12. Install the fuel ratio control over the shut-off strap. Make sure lever (5) is engaged correctly with compensation lever (12) and install the screws to hold the unit to the governor.

GOVERNOR ASSEMBLY
12. Compensation lever.

13. Make sure the O-ring seals are installed on the oil pressure line and into the fuel ratio control. Install junction block (13).

FUEL RATIO CONTROL OIL LINE
13. Junction block.

GOVERNOR COVER ASSEMBLY
14. Oil level gauge. 15. Cover assembly.

14. Install the shut-off actuator and cover assembly (15) on the fuel ratio control housing. Install oil level gauge (14) in the cover assembly.

15. Connect the engine oil pressure and air inlet pressure lines to the fuel ratio control housing.

Adjustment for Positive Droop

1. Remove the fuel ratio control from the governor. See Steps 1 through 6 in Adjustment for Zero Droop.

2. Connect a tachometer with good accuracy to the engine. Make reference to MEASURING ENGINE SPEED.

3. Loosen screw (9) and move droop cam (8) on droop lever (16) to get distance (A) for the droop percentage needed. See SPEED DROOP CHART to get the dimension needed.

SPEED DROOP ASSEMBLY
8. Droop cam. 9. Screw. 16. Droop lever. A. Speed droop setting.

NOTE: Dimension (A) is an approximate dimension. The final adjustments must be determined with the engine running.

4. Install the fuel ratio control on the governor. See Steps 12 through 16 in the Adjustment for Zero Droop. Start the engine and run to get the engine to the normal temperature of operation.

5. Put a load on the engine to get maximum full load. Make a note of the full load rpm.

6. Remove all load from the engine and make a note of the no load high idle rpm.

7. Find the difference of the no load high idle rpm and the full load rpm. Divide the difference by the full load rpm and multiply times 100. The result is the percent of speed droop.

8. If the speed droop is not correct, stop the engine and move droop cam (8) toward speeder plug (7) to increase speed droop, or move away from the speeder plug to decrease speed droop.

9. Do Steps 1 thru 8 to check the speed droop and adjust again if needed.

Fuel Ratio Control

The UG8 Lever governors are equipped with a fuel ratio control. Most adjustments are made at the factory or when the unit is rebuilt and there is a test bench available to make the adjustments. The following adjustment can be used to control acceleration smoke and engine response.

Adjustment

NOTE: Engine must be shutdown before making this adjustment to keep dirt and foreign material out of the governor.

1. Remove the cover assembly and shut-off actuator as a unit from the top of the governor.

2. Turn adjusting screw (1) clockwise to reduce smoke or counterclockwise to increase engine response.

3. Turn the adjusting screw 1/2 turn or less in the desired direction.

4. Replace the top cover assembly and shut-off actuator on the governor.

5. Start the engine and check the acceleration smoke and engine response to see if further adjustment is necessary. If necessary repeat Steps 1, 2 and 3.

LOCATION OF ADJUSTMENT SCREW
1. Adjusting screw.

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 in the air inlet or exhaust system.

Air flow through the air cleaner must not have a restriction (negative pressure difference measurement between atmospheric air and air that has gone through air cleaner) of more than 762 mm (30 in.) of water.

Back pressure from the exhaust (pressure difference measurement between exhaust at outlet elbow and atmospheric air) must not be more than 686 mm (27 in.) of water.

Measurement Of Pressure In Inlet Manifold

The efficiency of an engine can be checked by making a comparison of the pressure in the inlet manifold with the information given in the FUEL SETTING AND RELATED INFORMATION FICHE. This test is used when there is a decrease of horsepower from the engine, yet there is no real sign of a problem with the engine.

The correct pressure for the inlet manifold is given in the FUEL SETTING AND RELATED INFORMATION FICHE. Development of this information is done with these conditions:

a. 737 mm (29 in.) (dry) of mercury barometric pressure.

b. 29° C (85° F) outside air temperature.

c. 35 API rated fuel.

On a turbocharged aftercooled engine, a change in fuel rating will also change horsepower and the pressure in the inlet manifold. If the fuel is rated above 35 API, pressure in the inlet manifold can be less than given in the FUEL SETTING AND RELATED INFORMATION FICHE. If the fuel is rated below 35 API, the pressure in the inlet manifold can be more than given in the FUEL SETTING AND RELATED INFORMATION FICHE. BE SURE THAT THE AIR INLET AND EXHAUST DO NOT HAVE A RESTRICTION WHEN MAKING A CHECK OF PRESSURE IN THE INLET MANIFOLD.

PRESSURE TEST LOCATION
1. Inlet water elbow to aftercooler. 2. Elbow or plug for aftercooler air chamber pressure.

Use the 6V9450 Engine Pressure Group to check the pressure in the inlet manifold.

6V9450 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 instructions for its use.

Exhaust Temperature

6V5000 INFRARED THERMOMETER GROUP

Use the 6V5000 Infrared Thermometer Group to check exhaust temperature. Special Instruction Form No. SEHS8149 is with the tool group and gives instructions for the test procedure.

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 coming from the crankcase breather. This crankcase pressure can also cause the element for the crankcase breather to have a restriction in a very short time. It can also be the cause of oil leakage at gaskets and seals that would not normally have leakage.

Compression

An engine that runs rough can have a leak at the valves, or have valves that need adjustment. Removal of the head 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 5P944 Dowel Puller Group with a 5P942 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.

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 only time bridge adjustment is necessary is when a valve has been replaced, ground, or cylinder head has been reconditioned. 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 INJECTOR TIMING AND VALVE CLEARANCE SETTING.

1. Put engine oil on bridge dowel (4) in the cylinder head and in the bore in bridge (2).

2. Install bridge (2) with adjustment screw (5) toward the exhaust manifold.

BRIDGE INSTALLATION
1. Top contact surface. 2. Bridge. 3. Valve stem. 4. Bridge dowel.

3. Loosen the locknut for adjustment screw (5) and loosen the adjustment screw several turns.

4. Put a force of 5 to 45 N (1 to 10 lb.) by hand straight down on top contact surface (1) of bridge (2).

5. Turn adjustment screw (5) clockwise until it just makes contact with valve stem (3). 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
5. Adjustment screw.

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

TIGHTEN LOCKNUT

7. Put engine oil on top contact surface (1) where the rocker arm makes contact with the bridge.

Crankshaft Positions For Fuel Timing And Valve Clearance Setting

CYLINDER AND VALVE LOCATION (3512 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) 1000 service hours of operation, and every 3000 service 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 the 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 1000 service hours of engine operation.

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. 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.

4. 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

5. 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

6. 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.

7. 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.

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

9. 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 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. Oil with a thin viscosity can be caused by fuel leakage into the crankcase, or by increased engine temperature.

Measuring Engine Oil Pressure

6V9450 Engine Pressure Group.

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

6V9450 ENGINE PRESSURE GROUP

The 6V9450 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
6. 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 (6). 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 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 the bypass valve and bypass valve bore. Install new Caterpillar oil filters to be sure that no more debris makes the bypass valve 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 lower piston and ring temperatures. 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 passage 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.

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

8T470 Thermistor Thermometer Group.9S7373 Air Meter Group.6V3121 Multitach Group.9S8140 Cooling System Pressurizing Pump Group.

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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.

8T470 THERMISTOR THERMOMETER GROUP

The 8T470 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.

The 9S7373 Air Meter Group is used to check the air flow through the radiator core. The test procedure is in Special Instruction Form No. SMHS7063.

9S7373 AIR METER GROUP

The 6V3121 Multitach Group can be used to check the fan speed. Special Instruction Form No. SEHS7807 is with this group and gives instructions for the procedure.

6V3121 MULTITACH GROUP
1. Carrying case. 2. Power cable. 3. Tachometer generator. 4. Tachometer drive group. 5. Multitach.

Pressure Cap Test

9S8140 Cooling System Pressurizing Pump Group

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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.

TYPICAL SCHEMATIC OF PRESSURE CAP
A. Sealing surface of cap and radiator.

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.

One cause for a pressure loss in the cooling system can be a bad seal on the pressure cap of the system. 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, valve, seal, or surface that seals must be removed.

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

9S8140 COOLING SYSTEM PRESSURIZING PUMP GROUP

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.

Radiator and Cooling System Leak Tests (Systems That Use Pressure Cap)

9S8140 Cooling System Pressurizing Pump Group.

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.

9S8140 PRESSURIZING PUMP GROUP INSTALLED ON RADIATOR THAT USES PRESSURE CAP (TYPICAL EXAMPLE)

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 of 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.

Water Temperature Gauge Test

8T470 Thermistor Thermometer Group or2F7112 Thermometer and 6B5072 Bushing

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 8T470 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. Make reference to SPECIFICATIONS or ATTACHMENT SPECIFICATIONS in this manual to find correct range for a specific gauge.

Water Temperature Regulator Test

1. Remove the regulator from the engine.

2. Heat water in a pan until the temperature is 92°C (197°F). Move the water around in the pan to make it all the same temperature.

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

4. Keep the water 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.

V-Belt Tension Chart

Basic Block

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

8B7548 Puller Assembly (Crossbar).Two 3H465 Plates.Two 8F6123 3/4"-16NF Bolts, 140 mm (5.5 in.) long.Four Washers (3/4"-Copper).Four S1575 3/4"-16NF Bolts, 76 mm (3.0 in.) long.8T455 Liner Projection Tool Group.

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. 3H465 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 8T455 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 to 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

8T5096 Dial Indicator Group.

Heat the ring gear to install it. Do not heat to more than 315°C (600°F). Install the ring gear so the chamfer on the gear teeth are next to the starter pinion when the flywheel is installed.

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 crankshaft flange 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
A. Bottom. B. Right side. C. Top. D. Left side.

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

4. The difference between lower and higher measurements taken at all 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 column (B) & (D).

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

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

CHECKING BORE RUNOUT OF THE FLYWHEEL HOUSING

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

7. Turn the crankshaft 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 (if a torsional type).

Electrical System

Test Tools For Electrical System

6V4930 Battery Load Tester.8T900 AC/DC Clamp-On Ammeter.6V7070 Heavy-Duty Digital Multimeter or6V7800 Regular-Duty Digital Multimeter.

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 an 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 Load Tester.

8T900 AC/DC CLAMP-ON AMMETER

The 8T900 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 ammeter 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 complete information for use of the 8T900 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 checks 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 8T900 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.

Alternator Regulator Adjustment (Delco-Remy)

No adjustment can be made to change the rate of charge on these alternator regulators. If the rate of charge (ampere output) is within 10 amperes of rated output (marked on the alternator frame) the regulator is good. An over or under charged battery condition can be corrected sometimes by an adjustment to the voltage. If rate of charge is not correct, a replacement of the regulator is necessary.

When an alternator is charging the battery too much or not enough, an adjustment can be made to the output voltage of some alternators. Make reference to the SPECIFICATIONS section to find all testing specifications for the alternators and regulators.

Delco-Remy 24V 60A (4N3986 Alternator)

No adjustment of voltage output can be made on this alternator. If the voltage and ampere output is not correct, the alternator must be repaired or replaced.

Delco-Remy 32V 60A (4N3987 Alternator)

To make an adjustment to the voltage output, pull out voltage adjustment cap (1). Turn the cap 90° and install it again into the alternator. The voltage adjustment cap has four positions: HI, LO, and two positions between the high and the low setting.

The 4N3987 Alternator can be adjusted for either 30 or 32 volts. A replacement alternator shipped from the factory will be adjusted for 32V (16 battery cells) systems. Where the alternator is to be used in a 30V (15 battery cells) system, pull out voltage adjustment cap (1) and change from the HI position to position 3.

CAP TYPE REGULATOR ADJUSTMENT
1. Voltage adjustment cap.

Alternator Pulley Nut Tightening (Delco-Remy)

Tighten nut that holds the pulley to a torque of 100 ± 10 N·m (75 ± 5 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

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

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).

CONNECTION FOR CHECKING PINION CLEARANCE
1. Connector from MOTOR terminal on solenoid to motor. 2. SW terminal. 3. Ground terminal.

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 8.4 to 9.9 mm (.33 to .39 in.).

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