1674 DIESEL TRUCK ENGINE Caterpillar


Testing And Adjusting

Usage:

Introduction

NOTE: For Specifications with illustrations, make reference to ENGINE SPECIFICATIONS FOR 1674 DIESEL TRUCK ENGINE, Form No. REG01429. If the Specifications in Form REG01429 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 a problem with the engine can be a difficult job. It can be difficult because there can be more than one cause for a problem. Here is an important fact to remember. The list of problem, cause and correction on the following pages is only a guide to help solve the problem. The serviceman must use a step by step procedure and check all possible causes of a problem to accurately make a diagnosis.

Normally, more or other repair work is needed in addition to the recommendations in the list. Remember that a problem is not normally caused by only one part, but by the relation of one part with other parts. The serviceman must find the problems and their source, then make the necessary repairs.

1. Engine Will Not Turn When Start Switch Is On.
2. Engine Will Not Start.
3. Misfiring or Running Rough.
4. Stall at Low rpm.
5. Sudden Changes In Engine 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. Fuel 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. Too Much Black or Gray Smoke.
21. Too Much White or Blue Smoke.
22. Engine Has Low Oil Pressure.
23. Engine Uses Too Much Lubrication Oil.
24. Engine Coolant Is Too Hot.
25. Starting Motor Does Not Turn.
26. Alternator Gives No Charge.
27. Alternator Charge Rate Is Low or Not Regular.
28. Alternator Charge Too High.
29. Alternator Has Noise.
30. Exhaust Temperature Too High.

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. Finding the source of the problem is difficult, especially when smoke is coming from the exhaust. Smoke coming from the exhaust can be caused by a bad fuel injection valve, but it can also be caused by the following:

a. Not enough air for good combustion.
b. An overload at high altitude.
c. Burning of too much oil.
d. Not enough compression.

Fuel System Inspection

1. Look at the reading on the gauge for fuel pressure. Not enough fuel pressure is an indication of a problem with the components that send fuel to the engine.

2. 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.

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

4. Install a new fuel filter. Clean the primary fuel filter if so equipped.

5. Remove any air that may be in the fuel system.

6. Inspect the fuel bypass valve to see that there is no restriction to good operation.

7. Bleed the fuel system to remove trapped air.

Testing Fuel Injection Equipment

An easy check can be made to find the cylinder that is misfiring, or running rough, and causing black smoke to come out of the exhaust pipe.

Run the engine at the speed that gives misfiring. Loosen the fuel line nut at a fuel injection pump or valve. This will stop the flow of fuel to that cylinder. Do this for each cylinder until a loosened fuel line is found that makes no difference in engine running. Be sure to tighten each fuel line nut after the test before the next fuel line nut is loosened. Check each cylinder by this method. When a cylinder is found where the loosened fuel line nut does not make a difference in engine running, test the injection pump and injection valve for that cylinder.

Checking the Fuel Injection Valves

Check the fuel injection valves for:

1. Too much carbon on the tip of the nozzle or in the nozzle orifice.
2. Wear of the orifice.
3. Nozzle screen being dirty.

Use the Caterpillar Diesel Fuel Injection Test Bench to test the nozzle.

Checking Fuel Injection Pump Lifter Washer and Pump Plunger

The timing dimension should be checked to compensate for wear in the timing gears or pump lifters. This will assure that the point of the fuel injection is correct. If the timing dimension is too small, injection will begin early, and if too great, injection will be late.

When pump plunger wear becomes excessive, the lifter washer may also be worn so it will not make full contact with the end of a new plunger. To avoid rapid wear on the end of the new plunger, replace the lifters having washers showing visible wear.


These are patterns of wear between washer and plunger. Fig. A illustrates the contact surfaces of a new pump plunger and a new lifter washer. In Fig. B the pump plunger and lifter washer have worn considerably. Fig. C shows how the flat end of a new plunger makes poor contact with a worn lifter washer, resulting in rapid wear to both parts.

A pump can maintain a satisfactory discharge rate and yet be unserviceable because of delayed timing resulting from wear on the lower end of the plunger. When testing a pump which has been in use for a long time, check the plunger length with a micrometer. Discard the pump if the plunger measures less than the minimum length (worn) dimension.

Look for wear at the top part of the plunger. Check the operation of the plunger according to the instructions for the Fuel Injection Test Bench.

Fuel Injection Service

Injection Valve

Check the seat of the nozzle and the seat in the precombustion chamber before installing the fuel injection valve. It is important to keep the correct torque on the nut that hold the fuel nozzle in the precombustion chamber. Tighten the nut to 55 ± 5 lb. ft. (7.6 ± 0.7 mkg). There will be damage to the nozzle if the nut is too tight. If the nut is not tight enough the nozzle can leak.

Removal of Injection Pump

The fuel rack must be held at the center or "zero" position while removing or installing a fuel injection pump. An injection pump installed in the "fuel on" side of its gear segment can cause the engine to overspeed with resultant serious damage to the engine and driven equipment.

The rack is positioned at the center or "zero" position by using a centering pin, located under cover (1). To center the rack, move the rack to the fuel off position, loosen cover (1) and depress the centering pin into the slot in the rack.

NOTE: Hold pin down in the centered position by placing cover (1) partially over the centering pin, and tightening bolt finger tight.

Depress the speed limiter plunger, and move the governor control lever toward the fuel on position until the centering pin drops into the slot in rack. The rack is now centered.

When removing fuel injection pumps, spacers and lifters, the components should be kept together and marked so they can be installed in their respective location.

While disassembling fuel injection pumps, exercise considerable care to prevent damage to the plunger surfaces. The barrel and the plunger assembly are matched and the individual parts are not interchangeable with other barrels or plunger assemblies. Use extreme care when inserting the plunger into the bore of the barrel.


RACK CENTERING PIN
1. Cover.

Installation of Injection Pump

8S4613 Wrench.8S2244 Extractor.

The installation of fuel injection pump assemblies requires that the lifter be at a low point and the fuel rack be at the centered position. To install a fuel injection pump, proceed as follows.

1. Remove the air-fuel ratio control and depress the speed limiter.

2. Depress rack centering pin and move governor control lever in the fuel on direction. The rack centering pin will drop into a slot in the fuel rack and stop rack movement when the rack is in the centered position. Secure the rack linkage in this position.


RACK CENTERING PIN LOCATION
1. Cover. 2. Pin.

NOTE: Put the centering pin cover (1) partially over, the centering pin (2) and tighten the bolt finger tight to hold down the centering pin.

3. Align the notches (4) on the bonnet and barrel with the slot (5) of the pump gear segment.


ALIGNING NOTCHES WITH GEAR TOOTH
3. 8S2244 Extractor. 4. Notches. 5. Slot.

4. Put the injection pump into the housing. Slot (5) must align with the dowel in the lifter and the notches in the bonnet and barrel must align with the dowels in the pump bore. Keep a downward force on the pump and install the retaining bushing.


NOTICE

Do not force the pump assembly into the pump housing. Damage to the dowel in the lifter will result if the pump assembly is forced down.


5. When the fuel pump assembly is installed correctly the retaining bushing can be installed finger tight, flush with the top of the housing. If the bushing can not be installed this far finger tight, remove the bushing and pump assembly. Again align the components and again install the pump.

6. After the fuel pump assembly is installed correctly, tighten the bushing to 150 ± 10 lb. ft. (20.7 ± 1.4 mkg) with 8S4613 Wrench.

Finding Top Center Compression Position For No.1 Piston

2P8300 Engine Turning Tool.

No.1 piston on the compression stroke, at top center (TC) is the reference point for timing procedures.

Remove the valve cover. The four valves at the front of the engine are the inlet and exhaust valves for No.1 cylinder. All valves will be closed and the dash mark on the camshaft drive gear will align with the dash mark, marked "TIME" on the camshaft housing. Remove the cover (3) and plug (2).


TIMING BOLT LOCATION
1. Bolt to be used as timing bolt. 2. Plug. 3. Cover.

NOTE: Use 2P8300 Engine Turning Tool to rotate the flywheel.

1. Rotate the crankshaft counterclockwise (as viewed from the flywheel end of the engine) at least 30°. Continue rotating the crankshaft until the TC 1 and 6 cyl. mark is aligned with the timing pointer in the flywheel housing.

2. Install bolt (1) through the opening for plug (2) and into the threaded hole in flywheel.

NOTE: If timing hole is passed, do not back up, repeat Step 1 again.

NOTE: To check the timing of the overhead camshaft, install the timing pin into timing hole (5) between No.5 and No.6 cylinder inlet valves. The pin should engage a hole in the camshaft.


VALVE COVER REMOVED
4. Timing pin storage hole. 5. Timing hole.

Checking The Timing Of The Fuel Injection Pump Housing On Engine

Checking with 1P540 Flow Checking Tool Group

1P540 Flow Checking Tool Group.3S2954 Timing Indicator Group.9M9268 Dial Indicator.2P8294 Housing.2P8299 Pinion.

The timing of the fuel injection pump housing should be checked and reset if necessary to correct for slipped drive gear or worn timing gears.

See Special Instruction (FM035709) for complete instructions for the fuel flow method of engine timing (injection sequence).


MEASURING PISTON TRAVEL
1. 3S3263 Adapter. 2. 9M9268 Dial Indicator. 3. 3S3264 Rod. 4. Precombustion chamber. 5. Inlet port. 6. Piston. 7. Crankshaft.

Travel of piston (6), from point of closing inlet port (5) at top center, can be found by using the 3S2954 Timing Indicator Group. Change the travel of piston (6) into degrees to see if engine timing (injection sequence) is correct.

The 1P540 Flow Checking Tool Group is used to put pressure in the fuel system. Use the 1P539 Tank Assembly to get 10 to 15 psi (0.70 to 1.05 kg/cm2) fuel pressure.

See the chart to find angle relation to indicator reading. At the indicator reading and timing angle for this engine, fuel flow from the injection pump should be 6 to 12 drops per minute [point of closing inlet port (5)].

If the correct indicator reading is not on the dial indicator, it is possible that the camshaft for the fuel injection pumps needs timing. See, TIMING THE CAMSHAFT FOR THE FUEL INJECTION PUMPS. Several cylinders can be checked, and if there is a difference in the readings remove the fuel pump housing so all Lifter settings can be checked and an adjustment made. See, FUEL PUMP LIFTER SETTING (OFF ENGINE).

Checking the Timing of the Fuel Injection Pump with 1P3500 Injection Timing Group


1P3500 INJECTION TIMING GROUP

This group can be used to check injection timing. Special Instructions GMG00501 is part of the group and contains instructions for its use.

Fuel Injection Pump Camshaft Timing for Engines 94B1 - 94B3471

The timing should be checked and reset, if necessary, to account for worn timing gears or slipped drive gear. The timing can be set in the following manner.

1. Find top center (TC) compression for No.1 piston. Refer to FINDING TOP CENTER COMPRESSION POSITION FOR NO.1 PISTON.

2. Remove timing pin (2) and cover (1). Install timing pin (2) back into the hole it was taken out of, until the end of the pin engages the timing slot in the fuel injection pump camshaft. Timing pin must be free in timing slot of camshaft.


TIMING PIN LOCATION
1. Timing hole cover. 2. Timing pin.

3. If the timing pin will not engage the slot in the fuel injection pump camshaft, proceed as follows:

4. Remove the cover over the accessory drive gear. Loosen the four bolts (3) retaining the accessory drive gear to the variable timing drive shaft.


ACCESSORY DRIVE GEAR
3. Bolts (four).

5. Rotate the variable timing drive shaft until timing pin (2) engages the timing slot in the fuel injection pump camshaft. Timing pin (2) must be free in the camshaft slot.

6. Remove timing pin (2) and tighten bolts (3).

NOTE: At this time, remove all other timing pins from their timing holes.

7. Rotate flywheel counterclockwise two complete turns (as viewed from the flywheel end) and insert timing bolt into flywheel timing hole.

NOTE: If flywheel timing hole is passed, do not back up, repeat Step 7.

8. Fuel injection pump camshaft timing pin (2) should freely engage the timing slot in the fuel injection pump camshaft. If the fuel injection timing pin does not engage the slot in the fuel injection pump camshaft, repeat the complete timing procedure.

Fuel Injection Pump Camshaft Timing for Engines 94B3472-Up

The timing should be checked and reset, if necessary to correct because of worn timing gears or slipped drive gear. The timing can be set in the following manner:

1. Refer to FINDING TOP CENTER COMPRESSION POSITION FOR NO.1 PISTON. On these later engines with 6° timing advance, set the pointer on the 2° ATC mark (A). Do not install the long timing bolt in the flywheel.


TIMING MARKS ON FLYWHEEL
A. 2° After top center timing mark.

2. Remove timing pin (2) and cover (1). Install timing pin (2) back into the hole it was taken out of, until the end of the pin engages the timing slot in the fuel injection pump camshaft. Timing pin must be free in timing slot of camshaft.


TIMING PIN LOCATION
1. Timing hole cover. 2. Timing pin.

3. If the timing pin will not engage the slot in the fuel injection pump camshaft, proceed as follows:

4. Remove the cover over the accessory drive gear. Loosen the four bolts (3) retaining the accessory drive gear to the variable timing drive shaft.


ACCESSORY DRIVE GEAR
3. Bolts (four).

5. Rotate the variable timing drive shaft until timing pin (2) engages the timing slot in the fuel injection pump camshaft. Timing pin (2) must be free in the camshaft slot.

6. Remove timing pin (2) and tighten bolts (3).

NOTE: At this time, remove any other timing pins from their timing holes.

7. Rotate flywheel counterclockwise two complete turns (as viewed from the flywheel end) and align the 2° ATC mark (A) with the timing pointer.

NOTE: If flywheel is turned too far, do not back up, repeat Step 7.

8. Fuel injection pump camshaft timing pin (2) should freely engage the timing slot in the fuel injection pump camshaft. If the fuel injection pump timing pin does not engage the slot in the fuel injection pump camshaft, repeat the complete timing procedure.

Checking Fuel Pump Timing Dimension; On Engine

8S7167 Gauge.6F6922 Depth Micrometer with 4 to 5 in. (101.6 to 127.0 mm) rod.8S4613 Wrench.8S2244 Extractor.

This is only a check of the timing dimension. If the on engine dimension setting is incorrect for one pump, all pumps are probably incorrect. So if the timing dimension for one pump is incorrect, remove the pump housing and make the off engine setting of all pumps.

1. Turn the flywheel so the No.1 TC (top center) mark on the flywheel is aligned with the timing pointer.


TIMING MARK
B. 2° after top center mark.

On engines effective with 94B3472, the timing pointer should align with the 2° ATC (after top center) mark (B) on the flywheel.


CHECKING TIMING DIMENSION
1. Spacer. 2. 8S7167 Gauge. 3. 6F6922 Depth Micrometer with 4 to 5 in. (101.6 to 127.0 mm) rod. A. Timing dimension on engine with gauge is 4.353 to 4.357 in. (110.57 to 110.67 mm).

2. Remove the No.1 fuel injection pump with the 8S4613 Wrench and 8S2244 Extractor.

3. With the spacer (1) still in the pump housing, install the gauge (2) in the housing.

4. The on engine timing dimension can be read with the depth micrometer (3). The correct on engine dimension is 4.353 to 4.357 in. (110.57 to 110.67 mm). This dimension includes the 2 in. (50.8 mm) for the 8S7167 Gauge.

5. If the timing dimension is incorrect, check the accessory drive shaft timing. If the drive shaft timing is correct the fuel injection pump housing must be removed and all of the pumps have timing dimension setting made.

Fuel Pump Timing Dimension Setting; Off Engine


1P5600 TOOL GROUP
The tools in the list are the tools needed from the 1P5600 Tool Group to check or make lifter setting OFF ENGINE. 4. 1P7420 Pointer. 5. S1617 Bolt. 6. 1P7410 Timing Plate. 7. S509 Bolt. 8. 2S6160 Washer. 9. 8S2346 Shaft.


CHECKING TIMING DIMENSION (OFF ENGINE)
1. Spacer. 2. 8S7167 Gauge. 3. 6F6922 Depth Micrometer with 4 to 5 in. (101.6 to 127.0 mm) rod. Dimension "A" must be 2.3669 ± .0020 in. (60.119 ± 0.051 mm).

Proceed with off engine timing using an 8S7167 Gauge, 6F6922 Depth Micrometer, 4 to 5 in. (101.6 to 127.0 mm) rod. 1P7410 Plate Assembly (with an 8S2346 Shaft in place of the standard 7F8751 Shaft) and a 1P7420 Pointer Assembly.


POINTER INSTALLED
4. 1P7420 Pointer. 5. S1617 Bolt.

1. Install the pointer assembly on the fuel injection pump housing.

2. Place the timing plate on the drive end of the camshaft. Secure the plate to the camshaft.


CHECKING THE TIMING DIMENSION (OFF ENGINE)
2. 8S7167 Gauge. 3. 6F6922 Depth Micrometer. 4. 1P7420 Pointer. 6. 1P7410 Timing Plate. 7. S509 Bolt. 8. 2S6160 Washer.

3. Refer to the chart for the timing plate degree setting of the lifter being checked or set. Set the timing plate by rotating it counterclockwise until the correct degree setting aligns with the pointer assembly. Lock in position with the lockscrew.

4. The fuel injection pump timing dimension (off engine), using the 8S7167 Gauge is 4.390 to 4.394 in. (111.506 to 111.607 mm).

5. The spacer must be changed to change the timing dimension. Make reference to the spacer chart for spacer thickness.

6. If all timing dimensions are to be checked or reset, continue the same procedure in the firing order of the engine. Recheck each timing dimension after the adjustment has been made, to make sure the dimension is correct.

NOTE: At installation, the fuel injection pump camshaft must be timed to the engine crankshaft. See the topic FUEL INJECTION PUMP CAMSHAFT TIMING.

Fuel Rack Setting

9S240 Rack Positioning Tool Group.9M9268 Dial Indicator.8S4627 Circuit Tester.


NOTICE

A mechanic with training in rack adjustments is the only one to make adjustments to the rack setting. The correct settings are given in the book RACK SETTING INFORMATION.


The 9S240 Rack Positioning Tool Group makes it possible to set the rack, or measure rack position, during normal operation of the engine. The ability to observe rack position during operation provides much of the needed data to determine actual horsepower output and find the cause for lack of power.


9S240 RACK POSITIONING TOOL GROUP
1. 8S4627 Circuit Tester. 2. 9S238 Bracket. 3. 9M9268 Dial Indicator. 4. 9S8521 Rod. 5. 9S8518 Plug.

1. Refer to the book RACK SETTING INFORMATION for the correct rack setting dimension.

2. Disconnect the governor control linkage, at the most convenient location, so the governor control lever moves freely throughout its entire length of travel.

3. Remove the fuel ratio control from the rear of the governor, and remove the fuel rack cover and gasket from the front of the flange on the accessory drive housing.

4. Install the rack positioning tool group and dial indicator (3) over the opening for fuel rack cover on front flange of accessory drive housing. Let the spacer hang free as it is not used in this application. The gap between bracket (2) and housing is normal.


RACK SETTING TOOLS INSTALLED
2. 9S238 Bracket. 3. 9M9268 Dial Indicator.

5. Move governor control lever to the fuel off position. Loosen cover (6) and depress rack centering pin so it engages the slot in the rack.

NOTE: Hold pin down in centered position, by placing cover (6) partially over the centering pin, and tightening the retaining bolt finger tight.


CENTERING PIN COVER
6. Cover.

6. Depress the speed limiter plunger with rod (4) and move the governor control lever toward the fuel on position until the slot in the rack contacts the rack centering pin. The rack is now centered. Zero the dial indicator and remove rack centering pin.


DEPRESSING SPEED LIMITER PLUNGER
4. 9S8521 Rod.

7. Attach one end of the 8S4627 Circuit Tester (1) to the brass screw terminal on the outside of the governor housing.

8. With the speed limiter depressed, rotate the governor control lever toward the fuel on direction until the tester light comes on bright.

9. Slowly, rotate the governor control lever toward the fuel off position until the light goes out.

10. Now, again slowly rotate the governor control lever toward the fuel on position, until the tester light just barely comes on (a dim light); the rack collar is now just touching the stop bar or torque spring. Rack setting can now be read directly from the 9M9268 Dial Indicator (3).

11. If rack needs adjustment, be sure the engine is stopped. Remove the governor housing rear cover. Refer to one of the following rack adjustment topics for the correct procedure.

Rack Setting Adjustment for Engines 94B1-94B1681

Move governor control lever to the fuel off position.


RACK SETTING ADJUSTMENT (Earlier Engines)
1. Shims under stop bar.

Check adjustment by performing Steps 5 through 10 in the topic CHECKING FUEL RACK SETTING. Continue adjustment by add or remove shims (1) under the step bar to change rack setting. The reading on the dial indicator should be the same as the setting given in the book RACK SETTING INFORMATION.

Rack Setting Adjustment for Engines 94B1682-Up

Check adjustment by performing Steps 5 through 10 in the topic CHECKING FUEL RACK SETTING.

1. Move governor control lever to the fuel off position.

2. Loosen locknut (2) with wrench (3).

3. Turn adjusting screw (1) clockwise to decrease rack travel. Never adjust rack travel with shims.

4. Tighten locknut (2).

Continue adjustment procedure until the reading on the dial indicator is the same as the setting given in the book RACK SETTING INFORMATION.


RACK SETTING ADJUSTMENT (Later Engines)
1. Adjustment screw. 2. Locknut. 3. Wrench. 4. 9S5521 Rod.

Fuel Rack Setting with 7S7113 Rack Setting Gauge

Use this gauge to check and adjust rack setting with the fuel injection pump housing either installed, or removed from the engine.

1. Remove the rack cover from the front of the accessory drive housing rear flange and the cover from the rear of the governor housing.


7S7113 RACK SETTING GAUGE INSTALLED
1. Rack setting gauge.

2. Install the 7S7113 Rack Setting Gauge (1) over the front end of the fuel rack.

3. Set gauge to the rack setting. Refer to the book RACK SETTING INFORMATION for correct setting.

4. Depress the speed limiter plunger, and move the governor control lever to FULL LOAD position. The rack collar should just contact the stop bar or torque spring. Refer to the applicable topic RACK ADJUSTMENT.

Governor Adjustments


NOTICE

A mechanic with training in governor adjustments is the only one to make adjustments to the low and high idle rpm. The correct low and high idle rpm, and the rack setting dimensions for this engine, are given in the book RACK SETTING INFORMATION.


Engine rpm should be checked with an accurate tachometer.


HIGH AND LOW IDLE ADJUSTMENTS
1. Low idle adjusting screw. 2. High idle adjusting screw.

Low and high idle rpm can be adjusted by removing the cover at the rear of the governor, and turning the high idle and low idle adjusting screws. Turning either adjusting screw in a clockwise direction will decrease the respective high and low idle rpm. The retainer holes in the cover are shaped to prevent the screws from turning, after the adjustment has been made.

After setting the idle rpm, move the governor control lever to change the engine rpm. Return it to the idle position and recheck the idle rpm. Repeat the adjustment procedure until the specified idle rpm is obtained.

Fuel Ratio Control Test And Adjustment

Diaphragm

Make test with the fuel ratio control off the engine. Application of air pressure to chamber (3) through port (2) is needed to complete the test.

1. Application of 5 psi (0.35 kg/cm2) to chamber (3) must start movement of bolt (1).

2. Application of 16.5 to 20.5 psi (1.16 to 1.44 kg/cm2) pressure causes bolt (1) to be fully extended.

3. Pressure of 35 psi (2.46 kg/cm2), applied in the chamber (3), and then turned off, must not drop more than 2 psi (0.14 kg/cm2) in 10 seconds.


TESTING DIAPHRAGM
1. Bolt. 2. Port. 3. Chamber. 4. Bolts.

At installation put 8H5137 Sealant on threads of bolts (4) that hold the control to the governor.

Fuel Ratio Control Setting

8S4627 Circuit Tester.9S8521 Rod.

The fuel rack must be set correctly before setting the fuel ratio control. The same 8S4627 Circuit Tester can be used as for fuel rack setting. See, FUEL RACK SETTING.

1. Install the fuel ratio control when the governor control lever is in the fuel off position. Then move the governor control lever to the high idle position, with engine stopped, through the remainder of the setting procedure. Be sure the speed limiter is depressed with rod (4).

2. Remove the override control and cover.

3. Turn the cover (1) clockwise until the circuit tester light burns maximum output.

4. Turn the cover counterclockwise slowly until the circuit tester light burns minimum output. This will place the rack in the correct starting position. Mark the cover and base for adjusting purposes.


SETTING FUEL RATIO CONTROL
1. Cover. 2. Bolt. 3. Governor control lever. 4. 9S8521 Rod.

5. From the book RACK SETTING INFORMATION, get the figure for rack setting and subtract the figure given for fuel ratio control setting. From this, determine how many turns of the cover are required to adjust the control.

NOTE: In this application, one revolution counterclockwise of the cover causes .050 in. (1.27 mm) restriction in movement of the rack. Turning the cover the distance of one hole will give .008 in. (0.20 mm) adjustment to rack movement.

6. Turn the cover counterclockwise the number of turns plus any part of a turn for better hole alignment, to get the dimension nearest to that given in the book RACK SETTING INFORMATION.

7. Install the cover and remove the rack setting tools.

NOTE: Before starting the engine, make sure the governor control lever will move the governor to the fuel off position and that all parts operate freely.

With the above adjustment made, another adjustment can be made while the engine is running (if needed) to make an improvement to engine performance. To reduce exhaust smoke during speed increase, turn cover (1) out (less fuel) 1/2 turn at a time until operation is as needed. When exhaust smoke is as needed, but speed increase is slow, turn cover (1) in (more fuel) 1/2 turn at a time until operation is as needed.

NOTE: Some exhaust smoke is likely to appear at maximum speed increase.

If speed increase is slow and full engine power is lost, inspect the air line to the cover and the cover gasket for air leaks. If no air leaks are present, inspect the diaphragm. A damaged diaphragm will not permit the fuel rack to open completely, speed increase will be slow and full engine power will not be available.

Precombustion Chamber

Use the 8S225 Tool Group to remove and install chamber. Put 9M3710 Anti-Seize Compound and use either 5M2667, 1S9325, 1S9326 or 1S9327 gasket to position precombustion chamber.


PRECOMBUSTION CHAMBER POSITIONING DIAGRAM
A. Go range. B. No Go range. C. No Go range. D. No go range.

Install 5M2667 Gasket marked "2C". Install precombustion chamber and tighten to torque of 150 ± 10 lb. ft. (20.7 ± 1.4 mkg), If the glow plug opening is not positioned in the go range (A), remove the chamber. Replace gasket with the gasket marked "2F" if opening was in range (B), "2J" if opening was in range (C) and "2M" if opening was in range (D).

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 30 in. (762 mm) of water difference in pressure.

Back pressure from the exhaust (pressure difference measurement between exhaust outlet elbow and atmosphere) must not be more than 25 in. (635 mm) for naturally aspirated and 20 in. (508 mm) for turbocharged engines.

Measurement Of Pressure In Inlet Manifold

By checking the pressure in the inlet manifold the efficiency of an engine can be checked by making a comparison with the information given in the book, RACK SETTING INFORMATION. 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 book, RACK SETTING INFORMATION. Development of this information is done with these conditions: 29.4 in. (746.76 mm) of mercury barometric pressure, 60° F (15.5° C) outside air temperature and 35 API rated fuel. Any change from these conditions can change the pressure in the inlet manifold. Outside air that has higher temperature and lower barometric pressure than given above will cause a lower horsepower and inlet manifold pressure measurement, than given in the book, RACK SETTING INFORMATION. Outside air that has a lower temperature and higher barometric pressure will cause a higher horsepower and inlet manifold pressure measurement.

A difference 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 book, RACK SETTING INFORMATION. If the fuel is rated below 35 API, the pressure in the inlet manifold can be more than given in the book, RACK SETTING INFORMATION. BE SURE THAT THE AIR INLET AND EXHAUST DO NOT HAVE A RESTRICTION WHEN MAKING A CHECK OF PRESSURE IN THE INLET MANIFOLD.

Use the 4S6553 Instrument Group to check engine rpm and the pressure in the inlet manifold. This instrument group has a tachometer for reading engine rpm. It also has a gauge for reading pressure in the inlet manifold. Special Instruction (FE036044) is with the tool group and gives instructions for the test procedure.


4S6553 INSTRUMENT GROUP
1. 4S6992 Differential Pressure gauges. 2. Zero adjustment screw. 3. Lid. 4. 8M2743 Gauge. 5. Pressure tap fitting. 6. 4S6991 Tachometer. 7. 4S6997 Manifold Pressure Gauge.

Use the 1P3060 Pyrometer Group to check exhaust temperature. Special Instruction (GMG-00697) is with the tool group and gives instructions for the test procedure.


1P3060 PYROMETER GROUP

Crankcase (Crankshaft Compartment) Pressure

Broken or damaged pistons or piston rings 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.

Compression Check

2P8300 Engine Turning Tool Group.

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 fuel ignition, loosen a fuel line nut at a fuel injection pump or valve. This will stop the flow of fuel to that cylinder. Do this for each cylinder until a loosened fuel line is found that makes no difference in engine running. Be sure to tighten each fuel line nut after each cylinder test before the next fuel line nut is loosened. This test can also be an indication that the fuel injection is wrong, so more checking of the cylinder will be needed.

Condition of the valves, valve seats, pistons, piston rings and cylinder liners can be tested by putting air pressure in the cylinder. Special Instruction (GMG00694) gives instructions for the test procedure. It also gives the list of parts needed from Parts Department to make the test. 2P8300 Engine Turning Tool Group is needed for turning the engine.

This test is a fast method of finding the cause of compression loss in a cylinder. Removal of the head and inspection of the valves and valve seats is still necessary to find those small defects that do not normally cause a problem. Repair of these problems is normally done when reconditioning the engine.

Valves

Use the 5S1330 Valve Spring Compressor Assembly with the 5S1327 Jaw to put the valve spring under compression. Use the 5S1322 Valve Keeper Installer with the compressor assembly to make the installation of the valve keepers easier and faster.

Valve Seat Inserts

Valve seat inserts are available with a larger outside diameter than the original size. The available inserts are in the chart.

Valve Clearance Setting

Refer to LUBRICATION AND MAINTENANCE PROCEDURES for details of valve clearance adjustment.

Valve Guides

The intake and exhaust valves operate in replacement type valve guides. After the valves have been removed, clean the valve stems and valve guides.

The 7S5919 Driver and 7S8457 Bushing are used for installation of new valve guides.

Water Directors

There are twelve water directors (1) installed in the cylinder head. They give the coolant the desired direction of flow. They are installed on the exhaust valve side. The coolant flow goes toward the precombustion chambers and the exhaust valve ports.

Water directors are installed with a press in the heads after the alignment of the notch on the director with the V-mark on the head.

Replacement type seals (3) and ferrule (2) go between the head and top of the block. Put soap on the inner surface of the seal and put the seal over the flange on the ferrule before installing. Use the FT117 Seal and Ferrule Assembly Tool to install the seal on the ferrule.


WATER DIRECTORS
1. Water director. 2. Ferrule. 3. Seal.


FT117 SEAL AND FERRULE ASSEMBLY TOOL

4. 5H3182 Pin.

5. 2A3672 Spring.

6. Flat Washer.

7. Chain.

8. Upper Rod.

9. Connecting Pin.

10. Bracket.

11. Connecting Joint.

12. Lower Rod.

13. Base.

A. Rubber Seals.

B. Ferrule.

Lubrication System

One of the problems in the following list 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 WEARTURBOCHARGER LUBRICATION VALVE

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 is coming 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 three 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.
3. Compression ring not installed correctly.

Too much oil consumption can also be the result of using oil with the wrong viscosity. Oil with a thin (low) viscosity can be caused from dirt or fuel getting in the crankcase, or by the engine getting too hot.

Oil Pressure Is Low

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

When the engine is running at full load rpm with SAE 10 oil, temperature at 215 ± 10° F (102 ± 6° C), the oil pressure measured at the clean side of the oil filter at the oil filter base will be 60 ± 7 psi (4.6 ± 0.49 kg/cm2).

A lower pressure reading, 16 psi (1.12 kg/cm2), is minimum pressure at low idling speeds. An 8M2744 Gauge, which is part of 7S8875 Hydraulic Test Box, can be used for checking pressure in the system.


7S8875 HYDRAULIC TEST BOX

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 result in the oil pump not having 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 result in cavitation 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 pressure regulating valve for the system 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 and Oil Cooler Bypass Valves

If the bypass valve for the oil filter is held in the open position (unseated) and the oil filter has a restriction, a reduction in oil pressure can result.

The bypass valve is in the oil filter base. The bypass valve will cause the flow of oil to go around the filter elements when there is a reduction to the flow through the elements.

If the oil cooler has a restriction, the oil cooler bypass valve in the oil filter base will open. This will cause the flow of oil to go around the oil cooler.

Too Much Clearance at Engine Bearings or Open, Broken or Disconnected Oil Line or Passage in Lubrication System

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.

Oil Cooler

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 running. The oil pressure of the engine will become low if the oil cooler has a restriction.

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. A broken oil passage can also be the cause.

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

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 (too hot) point of water. The second advantage is that this type system prevents cavitation (air at inlet of pump) in the water pump. With this type system it is more difficult for an air or steam pocket to form in the cooling system.

The cause for an engine getting too hot is generally because regular inspections of the cooling system were not done. Make a visual inspection of the cooling system before testing with testing equipment.

Visual Inspection Of The Cooling System

1. Check coolant level in the cooling system.

2. Look for leaks in the system.

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

4. Inspect the drive belt for the fan.

5. Check for damage to the fan blades.

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

7. Inspect the pressure cap and the sealing surface for the cap. The sealing surface must be clean.

Testing The Cooling System

Remember that temperature and pressure work together. When making a diagnosis 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 altitude on the boiling (too hot) point of water.

Test Tools for Cooling System

9S9102 Thermistor Thermometer Group.9S7373 Air Meter Group.1P5500 Portable Phototach Group.9S8140 Cooling System Pressurizing Pump Group.

The 9S9102 Thermistor Thermometer Group is used in the diagnosis of heating problems. The testing procedure is in Special Instruction (GMG00450).


9S9102 THERMISTOR THERMOMETER GROUP

The 9S7373 Air Meter Group is used to check the air flow through the radiator core. The testing procedure is in Special Instruction (GMG00203).


9S7373 AIR METER GROUP

The 1P5500 Portable Phototach Group is used to check the fan speed. The testing procedure is in Special Instruction (GMG00819).


1P5500 PORTABLE PHOTOTACH GROUP

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


9S8140 COOLING SYSTEM PRESSURIZING PUMP GROUP

Gauge for Water Temperature

9S9102 Thermistor Thermometer Group.2F7112 Thermometer.

If the engine gets too hot and loss of coolant is a problem, a pressure loss in the cooling system could be the cause. If the gauge for water temperature shows that the engine is getting too hot, look for coolant leakage. If a place can not be found where there is coolant leakage, check the accuracy of the gauge for water temperature. Use the 9S9102 Thermistor Thermometer Group. This check can also be made by installing a 2F7112 Thermometer (with a suitable bushing) into the water manifold.


NOTICE

Be careful when working around an engine if it is running.



THERMOMETER INSTALLED
1. 2F7112 Thermometer.

Start the engine. Put a cover over part of the radiator or cause a restriction of coolant flow. The reading on the gauge for water temperature should be the same as the reading on the thermistor thermometer.

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 the sealing surface. Any foreign material or deposits on the cap, seal or sealing surface must be removed.

Temperature Regulator

The temperature that makes the 9S9160 Regulator start to open is 162 to 167° F (72 to 75° C). The regulator is to be fully open at 187° F (86° C).

The temperature that makes the 4L7615 Regulator start to open is 164 to 166° F (73 to 74° C). The regulator is to be fully open at 180° F (82° C).

1. Remove the regulator from the engine.

2. Put the regulator and a thermometer in suspension in a pan of water.

3. Put heat to the pan to get the temperature of the water hotter. Make the water move around in the pan so all of the water will be the same temperature.

4. Check the temperature of the water when the thermostat starts to open. If the regulator does not operate correctly, install a new regulator.

NOTE: When installing a regulator inspect seal for defects and change if necessary.

Basic Block

Connecting Rods And Pistons

Use the 7S9470 Piston Ring Expander to remove or install piston rings.

Use the 7S9417 Piston Ring Compressor to install pistons into cylinder block.

Tighten the connecting rod bolts in the following step sequence:

1. Put crankcase oil on threads.

2. Tighten both nuts to 30 ± 3 lb. ft. (4.1 ± 0.4 mkg).

3. Put a mark on each nut and cap.

4. Tighten each nut 90° from the mark.

The connecting rod bearings should fit tightly in the bore in the rod. If bearing joints or backs are worn (fretted), check for bore size as this is an indication of wear because of looseness.

Connecting Rod And Main Bearings

Bearings are available with .010 in. (0.254 mm), .020 in. (0.508 and .030 in. 0.762 mm) smaller inside diameter than the original size bearings. These bearings are for crankshafts that have been "ground" (made smaller) than the original size.

Projection Of Cylinder Liner

1P2394 Puller Plate.8B7548 Push Puller Crossbar and three3H465 Plates.8S3140 Cylinder Block Counterboring Tool Arrangement.1P5510 Liner Projection Tool Group.

1. Make certain that top plate (4) and the cylinder liner flange are clean. Install liners without seals at the bottom and band at the top under the flange of the liner.

2. Use 5/8 in. - 11 NC bolts, with two 2S736 Washers (3) on each bolt to secure top plate (4) to the cylinder block. Place two bolts with washers on each side of the cylinder liner. Tighten the bolts evenly, in four steps; 10 lb. ft. (1.4 mkg), 25 lb. ft. (3.5 mkg), 50 lb. ft. (6.9 mkg) and finally to 70 lb. ft. (9.7 mkg).

NOTE: To avoid moving bolts and washers as each liner is checked, install two bolts with washers on each side of each cylinder liner, along the entire length of the top plate.


SECURING TOP PLATE TO CYLINDER BLOCK (Typical Example)
1. 3H465 Plate. 2. 1P2394 Adapter plate. 3. Cylinder head bolt washers. 4. Top plate.

3. Invert 3H465 Plate (1) from an 8B7548 Push Puller, in the center of adapter plate (2). Center crossbar (6) on the inverted 3H465 Plate. Using two 5/8 in. - 11 NC bolts and two 3H465 Plates, secure the crossbar to the cylinder block as illustrated. Tighten the bolts evenly, in four steps; 5 lb. ft. (0.7 mkg), 15 lb. ft. (2.1 mkg), 25 lb. ft. (3.5 mkg) and finally to 50 lb. ft. (6.9 mkg). Distance from bottom edge of crossbar to top plate, must be the same on both sides of cylinder liner.

4. Use a 1P5510 Liner Projection Tool Group to measure liner projection. Special Instruction (GMG00623) is included with the tool.

5. Measure liner projection as close as possible to the clamping area and at four locations around the liner. The liner projection must be within .0030 to .0076 in. (0.076 to 0.193 mm) and the four measurements should not vary more than .001 in. (0.03 mm). The average projection between adjacent cylinders must not vary more than .001 in. (0.03 mm).


MEASURING LINER HEIGHT PROJECTION (Typical Example)
5. Dial indicator. 6. Crossbar. 7. 1P2402 Block.

NOTE: If liner projection varies from point to point around the liner, rotate the liner to a new position within the bore. If still not within specified limits, move liner to a different bore.

NOTE: When liner projection is correct, mark the liner and top plate so when seals and band are installed, the liner can be installed in the correct position.

NOTE: Measure and check the following dimensions when installing new parts. With all dimensions correct, proceed with the above listed Steps.

a. Top plate thickness, .3925 ± .0005 in. (9.969 ± 0.013 mm).
b. Top plate gasket thickness, .008 ± .001 in. (0.20 ± 0.03 mm). (All surfaces must be clean and dry when installing gasket.)
c. Cylinder liner flange thickness .4048 ± .0008 in. (10.282 ± 0.020 mm).

6. Use the 8S3140 Counterboring Tool Arrangement to machine the contact face on block if needed. Special Instruction (FM055228) gives an explanation of the use of the 8S3140 Counterboring Tool Arrangement.

Adjustment Shims For Liner Projection

Cylinder Block

The bore in the block for main bearings can be checked with the main bearing caps installed without bearings. Tighten the nuts holding the caps to the torque shown in the SPECIFICATIONS, Form No. REG01362. Alignment error in the bores must not be more than .003 in. (0.08 mm). Special Instruction (GMG00503) gives the use of 1P4000 Line Boring Tool Group to machine the main bearing bores. 1P3537 Dial Bore Gauge Group can be used to check the size of the bores. Special Instruction (GMG00981) is with the group.

Flywheel And Flywheel Housing

Heat ring gear to install. Do not exceed 600° F. (315° C.). Install ring gear so chamfered portion of gear teeth face the starter pinion when flywheel is installed.

Checking Flywheel Housing Face Runout

Make tool setup from parts of the 8S2328 Dial Test Indicator Group.


CHECKING FLYWHEEL HOUSING FACE RUNOUT
A. Bottom. B. Right side. C. Top. D. Left side.

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

2. Pry the crankshaft to rear before taking readings at each point.

3. With dial indicator set at .000 in. (0.0 mm) at point (A), rotate crankshaft and take readings at points (B), (C) and (D).

4. The difference between the lowest and highest readings taken at all four points should not exceed .012 in. (0.30 mm), which is the maximum permissible flywheel housing face runout.

Checking Flywheel Housing Bore Runout

Make tool setup from parts of the 8S2328 Dial Test Indicator Group.

1. Fasten the dial indicator to the crankshaft flange and adjust it to read .000 in. (0.0 mm) when the anvil is touching bore at point (1).

2. Pry the crankshaft in such a manner to remove crankshaft main bearing clearance when taking readings at each point.

3. Rotate crankshaft and take readings at points (2), (3) and (4).

4. The difference between the lowest and highest readings taken at all four points should not exceed .012 in. (0.30 mm), which is the maximum permissible flywheel housing bore runout.


CHECKING FLYWHEEL HOUSING BORE RUNOUT
1. Bottom. 2. Right side. 3. Top. 4. Left side.

NOTE: If any method other than described here is used, always consider bearing clearances to obtain correct readings.

Checking Flywheel Face Runout

Make tool setup from parts of the 8S2328 Dial Test Indicator Group and a bolt with the same size thread as the holes in face of flywheel housing and two flat washers.

1. Mount a dial indicator as shown and pry the crankshaft in the same direction before taking all readings so the end clearance is always in the same direction.

2. Set the dial indicator to read .000 in. (0.0 mm).

3. Turn the flywheel and take readings every 90°.


CHECKING FLYWHEEL FACE RUNOUT

4. The difference between the lowest and highest readings taken at all four points should not exceed .006 in. (0.15 mm), which is the maximum permissible flywheel face runout.

Checking Flywheel Bore Runout


CHECKING FLYWHEEL BORE RUNOUT
1. 7H1945 Holding Rod. 2. 7H1645 Holding Rod. 3. 7H1942 Indicator. 4. 7H1940 Universal Attachment.

Make tool setup from parts of the 8S2328 Dial Test Indicator Group.

1. Mount the dial indicator and adjust it so the universal attachment contacts the flywheel bore as shown.

2. Adjust the dial indicator to read .000 in. (0.0 mm) then take readings every 90° around the flywheel.

3. The difference between the lowest and highest readings taken at all four points should not exceed .006 in. (0.15 mm), which is the maximum permissible flywheel bore runout. Flywheel clutch pilot bearing bore runout should not exceed .005 in. (0.13 mm).


CHECKING FLYWHEEL CLUTCH PILOT BEARING BORE

Electrical System

Most of the testing of the electrical system can be done on the engine. The wiring insulation must be in good condition, the wire and cable connections clean and tight and the battery fully charged. If on the engine test shows a defect in a component, remove the component for more testing. The wire size, color and recommendations of length are given in the WIRING DIAGRAMS in SYSTEMS OPERATION.

Battery

9S1990 Battery Charger Tester.

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 charging. 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.


9S1990 BATTERY CHARGER TESTER


NOTICE

Never disconnect any charging unit circuit or battery circuit cable from battery when the charging unit is charging.


Load test a battery that does not hold a charge when in use. To do this, put a resistance, across the battery main connections (terminals). For a 6 volt battery, put a resistance of two times the ampere/hour rating of the battery. For a 12 volt battery, put a resistance of three times the ampere/hour rating. Let the resistance remove the charge (discharge the battery) for 15 seconds. Immediately test the battery voltage. A 6 volt battery in good condition will test 4.5 volts; a 12 volt battery in good condition will test 9 volts.

The Special Instruction (GEG00058) with the 9S1990 Charger Tester gives the battery testing procedure.

Charging System

Battery

The condition of charge in the battery at each regular inspection will show if the charging system is operating correctly. An adjustment is necessary when the battery is always in a low condition of charge or a large amount of water is needed (one ounce per cell per week or every 50 service hours).

Test the charging units and voltage regulators on the engine, when possible, using wiring and components that are a permanent part of the system. Off the engine (bench) testing will give an operational test of the charging unit and voltage regulator. This testing will give an indication of needed repair. Final testing will give proof that the units are repaired to their original operating condition.

Before starting on the engine testing, the charging system and battery must be checked. See the following Steps.

1. Battery must be at least 75% (1.240 Sp. Gr.) full 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 proper circuit control.

4. Inspect the drive components for the charging unit to be sure they are free of grease and oil and are able to drive the load of the charging unit.

Alternator Regulator

When an alternator is charging the battery too much or not enough, an adjustment can be made to the charging rate of the alternator. Remove the hollow head screw (1) from the cover of the alternator regulator and use a screwdriver to turn the adjustment screw. Turn the adjustment screw one or two notches to increase or decrease the charging rate of the alternator.


LOCATION OF ADJUSTMENT SCREW FOR THE 6L5397 and 6L3432 ALTERNATOR REGULATORS
1. Hollow head screw. 2. Connector.

Starting System

Use a D. C. Voltmeter to find starting system components which do not function.

Move the starting 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. The solenoid operation also closes the electric circuit to the motor. Connect one lead of the voltmeter to the solenoid connection (terminal) that is fastened to the motor. Ground the other lead. Activate the starter solenoid and look at the voltmeter. A reading of battery voltage shows the problem is in the motor. The motor must be removed for further testing. No reading on the voltmeter shows that the solenoid contacts do not close. This is an indication the need for repair to the solenoid or an adjustment to be made to starter pinion clearance. Pinion clearance is .36 in. (9.14 mm).

If the solenoid for the starting motor will not operate, current from the battery may not be getting to the solenoid. Fasten one lead of the voltmeter to the connection (terminal) for the battery cable on the solenoid. Ground the other lead. No voltmeter reading shows there is a broken circuit from the battery. Further testing is necessary when there is a reading on the voltmeter.

Further test by fastening one voltmeter lead to the connector (terminal) for the small wire at the solenoid and the other lead to the ground. Look at the voltmeter and activate the starter solenoid. A voltmeter reading shows that the problem is in the solenoid. No voltmeter reading shows that the problem is in the starter switch or wiring. Fasten one lead of the voltmeter to the battery wire connection of the starter switch and ground the other lead. A voltmeter reading indicates a failure in the switch.

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

Pinion Clearance Adjustment (Delco-Remy)

Whenever the solenoid is installed, make an adjustment of the pinion clearance. The adjustment can be made with the starting 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 connection (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 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.

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

6. Pinion clearance (6) must be .36 in. (9.14 mm).

7. Pinion clearance adjustment is made by removing plug and turning nut (4).


PINION CLEARANCE ADJUSTMENT
4. Shaft nut. 5. Pinion. 6. Pinion clearance.

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