1673 DIESEL TRUCK ENGINE Caterpillar


Testing And Adjusting

Usage:

Problem Solving

Index

1. Engine Fails to Start
2. Misfiring
3. Stalls at Low Speed
4. Erratic Engine Speed
5. Low Power
6. Excessive Vibration
7. Heavy Combustion Knock
8. Valve Train Clicking Noise
9. Oil in Coolant
10. Mechanical Knock
11. Excessive Fuel Consumption
12. Loud Valve Train Noise
13. Little Rocker Arm Movement and Excessive Valve Lash
14. Valve Rotocoil Spring Retainer Free
15. Slobber
16. Valve Lash Close-up
17. Premature Engine Wear
18. Coolant in Engine Lubricating Oil
19. Excessive Black or Gray Smoke
20. Excessive White or Blue Smoke
21. Low Engine Oil Pressure
22. High Lubricating Oil Consumption
23. Abnormal Engine Coolant Temperature
24. Starting Motor Fails to Crank
25. Alternator or Generator Fails to Charge
26. Alternator or Generator Charging Rate Low or Unsteady
27. Alternator or Generator Charging Rate High
28. Noisy Alternator or Generator

Air Induction And Exhaust System

Restriction Of Air Inlet And Exhaust

Engine horsepower and efficiency will be reduced if either the air inlet or exhaust system becomes restricted. The air cleaner should not restrict air flow to the point of 30" (762 mm) of water difference in pressure.

Exhaust back pressure (pressure difference measured between the turbocharger outlet elbow tap and the ambient air) should be no more than 27" (686 mm) of water.

Measuring Inlet Manifold Pressure

This test should be used if engine horsepower seems to be too low, yet no specific symptom of engine trouble is apparent.

Inlet manifold pressures in the RACK SETTING INFORMATION are recorded under specific operating conditions: 29.4 inches (746,76 mm) of mercury barometric pressure, 85° F. (29.4° C.) ambient temperature and 35 API rated fuel. Any deviation from these conditions can affect the inlet manifold pressure. Ambient air which is denser than that at 85° F./29.4 inches (29.4° C/746,76 mm) of mercury, can cause a slightly higher horsepower and inlet manifold pressure rating can be slightly lower than the values given in the RACK SETTING INFORMATION. Fuel density (API gravity rating) also affects the horsepower and inlet manifold pressure. If the fuel is rated above the standard 35 API gravity rating, the inlet manifold pressure can be slightly less than the value given in the RACK SETTING INFORMATION. If the fuel is rated below the standard rating, the inlet manifold pressure can be slightly more. Be sure the air cleaner and exhaust are not restricted when checking inlet manifold pressure.

The components in a 4S6553 Instrument Group provide a means of reading engine RPM and inlet manifold pressure simultaneously. This group contains an instantaneous reading tachometer, and a gauge for reading inlet manifold pressure. Instructions (FE036044) included with this group, explain the testing procedure.

Crankcase Pressure

Excessive crankcase pressure can be a result of combustion gas leaking past broken or damaged pistons and/or piston rings. This condition will usually be accompanied by irregular engine operation and excess fumes from crankcase breather opening. This pressure can cause the breather element to become restricted in an unusually short time. In addition, it can cause engine oil to leak past gaskets and seals that would function properly under normal conditions.

Compression

Irregular (rough) engine operation can be caused by improperly adjusted or leaky valves. Operate the engine at RPM which makes the malfuction most pronounced. A non-firing or low compression cylinder can be located by momentarily loosening and then retightening fuel lines at the fuel injection pumps one at a time. Continue this until a loosened fuel injection line makes little or no difference in the engine operation. This same test can also indicate faulty fuel injection so further checking of the cylinder is necessary.

Cylinder Condition

Engine cylinder condition can be analyzed with controlled pressure air through the engine cylinder precombustion chamber. Special Instruction (GMG00694) explains the procedure.

3B7762 Tee3B7767 Nipple6K6875 Hose Assembly8M2744 Gauge1P5569 Tip7S8890 Adapter7S8895 Adapter8S2268 Tube Assembly9S7341 AdapterAir pressure regulator

Air escaping from the exhaust opening indicates exhaust valve leakage. Air escaping from the air inlet indicates inlet valve leakage. If air escapes from the crankcase breather during this test, it is an indication of piston, rings and/or liner faults.


MEASURING AIR FLOW
1-Air regulator. 2-6K6875 Hose Assembly and 7S8895 Adapter. 3-8S2268 Tube Assembly and 9S7341 Adapter. 4-8M2744 Gauge (0-100 PSI). 5-7S8890 Adapter. Parts not shown: 3B7762 Tee, 3B7767 Nipple, 1P5569 Tip.

Cylinder Head

Original equipment cylinder heads for turbo-charged engines are equipped with valve seat inserts. Valve seat inserts are installed in replacement cylinder heads for all engines.

Tools required to install valve guides are: 7S8858 Driver Bushing and 7S8859 Driver. The counterbore in the driven bushing mates with the counterbore in the cylinder head to limit driving the guide.

Valve Clearance Setting


ADJUSTING VALVE CLEARANCE

Precombustion Chamber Position

Use 5F8353 Wrench to remove and install chamber. Coat threads with 9M3710 Anti-Seize Compound.


PRECOMBUSTION CHAMBER POSITION
Install thinnest gasket first. Install precombustion chamber and tighten to 150 ± 10 lb. ft. (20,7 ± 1,4 mkg). If the glow plug opening is not positioned in the "go" range, remove the chamber and replace gasket with that called for in the diagram.

Use gaskets to position precombustion chambers to prevent wiring interference.

Fuel System

Difficulty within the fuel system can be classed in one of two groups: lack of fuel or too much fuel for proper combustion.

Many times the fuel system is blamed when the fault lies elsewhere, especially when smoky exhaust is the problem. Smoky exhaust can be the result of a faulty fuel injection valve, but it can also be caused by lack of air for complete combustion, overloading at high altitude, excessive oil burning or lack of compression.

Visual Inspection

1. Observe the fuel pressure gauge reading. Lack of pressure indicates difficulty in the supply side of the system.

2. Check the fuel level in the supply tank and the fuel tank cap vent for being plugged.

3. See that the vent valve is closed.

4. Check for leakage in the fuel supply lines and components or for a kinked or restricted supply line.

5. Replace the fuel filter element and clean the primary fuel filter if so equipped.

6. Inspect the fuel bypass valve to see that it moves freely and that dirt is not holding the plunger off its seat. Be certain the spring has correct tension.

7. Bleed the fuel system to remove trapped air.

Testing Fuel Injection Equipment

A simple check can be made to determine which cylinder is misfiring or causes puffing black smoke. With the engine running at a speed which makes the defect most pronounced, momentarily loosen the fuel line nut on the injection pump sufficiently to "cut out" the cylinder. Check each cylinder in the same manner. If one is found where loosening makes no difference in the irregular operation or causes puffing black smoke to cease, the pump and valve for only that cylinder need be tested.

Checking Fuel Injection Valve

Examine fuel injection valves for:

1. Excessive carbon on tip of nozzle or in orifice.
2. Erosion of the orifice.
3. Screen plugged with dirt.

The condition of a capsul-type nozzle assembly can be tested on the Caterpillar Diesel Fuel Injection Test Apparatus, and the rate of leakage of the nozzle assembly can be determined.

Checking Fuel Injection Pump Lifter Washer and Pump Plunger

The timing dimension should be checked and adjusted, if necessary, by setting the fuel injection pump timing dimension with the fuel injection pump off the engine. 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.


WEAR BETWEEN LIFTER 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.

Inspect the upper diameter of the plunger for wear. Performance of pumps worn in this manner can be checked as described in the Instructions for Fuel Injection Test Apparatus.

Fuel Injection Service

Fuel Injection Valve

When installing a fuel injection valve, always check the seats of both the nozzle and the precombustion chamber. The nozzle assembly should be only finger-tight on the body. It is important to maintain the nozzle retaining nut torque to 105 ± 5 lb. ft. (14,5 ± 0,7 mkg). EXCESSIVE TORQUE will damage the nozzle. LESS TORQUE will allow the nozzle to leak and may cause the nozzle case to bulge or split.

Fuel Injection Pump

Use an 8S4613 Wrench and 8S2244 Extractor to remove and install fuel injection pumps.

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

While disassembling fuel injection pumps, exercise considerable care to prevent damage to the plunger surfaces. The barrel and the plunger are matched and are not interchangeable. Use extreme care when inserting the plunger into the bore of the barrel.

Fuel Pump Installation

The installation of fuel injection pumps requires that the lifter be at a low point and the fuel rack be centered or at "zero" position. To center or "zero" the rack, install the 7S7113 Rack Setting Gauge and set it at .000 in., retract the speed limiter, and move the rack in "fuel on" direction until it contacts the gauge. To install the pump, sight down the pump and align notches in bonnet and barrel with slot in the pump gear segment. Slot is 180° from pump gear segment center tooth. Position the notches in bonnet and barrel to align with dowels in the housing. Install the pump. Keep a downward force (by hand) on the pump and install the bushing finger tight, until flush with top of housing. If the bushing cannot be assemblied this far finger tight, remove the bushing and pump. The threads, on the bushing or in the housing, can be the restriction. Align the pump components and reinstall it. If the bushing installs correctly, tighten it to a torque of 150 ± 10 lb. ft. (20,7 ± 1,4 mkg). Overtightening the bushing can damage the housing or if the bushing is not tight enough, the pump will leak.


RACK SETTING GAUGE INSTALLED
1-7S7113 Rack Setting Gauge. A 9S240 Rack Positioning Tool Group can also be used.

Total rack travel, approximately .800 in. (20,32 mm), will be reduced if the pump is installed one or more teeth off in either the "fuel on" or "fuel off" side of its gear segment. The only way to check for correct installation of pumps with engine stopped is to measure full rack travel with the entire governor removed, including piston and valve mechanism.

Fuel Bypass Valve

The fuel bypass valve should control fuel pressure to the fuel injection pump at full speed to a pressure of 25 to 32 PSI (1,76 to 2,25 kg/cm2).

Locating Top Center Compression Position For No. 1 Piston

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


LOCATING TOP CENTER
1 - Timing pointer (aligned with mark on flywheel).

Remove the timing pointer cover from the flywheel housing. Rotate the engine crankshaft counterclockwise (as viewed from the flywheel end) at least 60° until the mark TC 1 & 6 cyl., on the flywheel, is aligned with timing pointer (1) when the No. 1 cylinder is on the compression stroke.

If the valve and rocker arm cover has been removed, the No. 1 cylinder inlet and exhaust valves (the two valves at the front of the engine) are closed when No. 1 cylinder is on compression.

Fuel System Adjustments

Checking Fuel Injection Pump Timing-On Engine

The timing dimension should be checked and reset, if necessary, to account for slipped accessory drive shaft coupling or worn timing gears. The timing dimension can be checked in either of the following manners.

Checking with 1P540 Flow Checking Tool Group and 3S2954 Timing Indicator Group

3S2954 Timing Indicator Group9M9268 Dial Indicator1P540 Flow Checking Tool Group

Refer to Special Instruction (FM035709) for complete and detailed instructions for the fuel flow method of engine timing.


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) to top center, can be found by using the 3S2954 Timing Indicator Group. Convert the travel of piston (6) into degrees to determine if engine timing is correct.

The 1P540 Flow Checking Tool Group is used to pressurize the fuel system. Maintain 10-15 PSI (0,7-1,05 kg/cm2) fuel with the 1P539 Tank Assembly. This can be done with hand pump provided with the tank assembly or connecting shop air to the tank assembly.

Consult the chart to find the angle corresponding to the indicator reading. At the indicator reading and timing angle specified, fuel flow from the injection pump should be reduced to 6-12 drops per minute [point of closing inlet port (5)].

Checking with 8S4618 Gauge

8S4618 Fuel Pump Lifter Gauge8S4613 Wrench, 8S2244 Extractor.

1. Locate (TC) compression position for No. 1 piston.


FUEL PUMP LIFTER GAUGE INSTALLED 1-8S4618 Gauge.

2. Remove No. 1 fuel injection pump with 8S4613 Wrench and 8S2244 Extractor. Insert fuel pump lifter gauge (1) into fuel pump bore (4).

3. With gauge seated in fuel pump housing, the higher step of the plunger (2) must be slightly above the top surface of the gauge body (3). The lower step of the plunger must be just below the top surface of the gauge body.


FUEL PUMP LIFTER GAUGE INSTALLED
1-Fuel pump lifter gauge. 2-Plunger. 3-Gauge body. 4-Fuel pump bore.

4. If the plunger in the gauge is not in the position stated in Step 3, check the accessory drive shaft timing. See the topic, ACCESSORY DRIVE SHAFT TIMING.

5. If the accessory drive shaft timing is correct and the lifter gauge plunger was not in the position stated in Step 3, the pump timing setting must be corrected. See the topic, FUEL INJECTION PUMP TIMING DIMENSION SETTING-OFF ENGINE.

Checking with 8S7167 Gauge

8S7167 Gauge6F6922 Depth Micrometer [4-5 in. (101,6-127,0 mm) rod]8S4613 Wrench, 8S2244 Extractor

1. Locate (TC) compression position for No. 1 piston.

2. Remove No. 1 fuel injection pump with 8S4613 Wrench and 8S2244 Extractor. Insert gauge (2) into the housing fuel pump bore.

3. The correct depth micrometer (1) timing dimension setting is 4.2159-4.2199 in. (107,08-107,18 mm).


CHECKING TIMING DIMENSION SETTING
1-6F6922 Depth Micrometer with 4-5 in. (101,6-127,0 mm) rod. 2-8S7167 Gauge.

4. If the timing dimension setting measurement is not correct, check the accessory drive shaft timing. See the topic, ACCESSORY DRIVE SHAFT TIMING.

5. If the accessory drive shaft timing is correct and the timing dimension setting measurement was incorrect, the timing setting must be corrected. See the topic, FUEL INJECTION PUMP TIMING DIMENSION SETTING-OFF ENGINE.

Fuel Injection Pump Timing Dimension Setting-Off Engine

1F8747 Timing Plate,8S7167 Gauge,8S4613 Wrench and8S2244 Extractor.6F6922 Depth Micrometer [4-5 in. (101,6-127,0 mm) rod].

The off engine setting adjusts for wear in the fuel injection pump housing only. The accessory drive shaft timing adjusts for wear in the timing gears, accessory drive shaft and fuel pump camshaft coupling.

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

2. Place 1F8747 Timing Plate on the drive end of the camshaft. Secure the plate to the camshaft.

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

NOTE: Fuel injection pump removal is made with an 8S4613 Wrench and 8S2244 Extractor.

4. The fuel injection pump timing dimension (off engine), using the 8S7167 Gauge is 4.2675 ± .0005 in. (108,395 ± 0,013 mm).

5. If the timing dimension is .002 in. (0,05 mm) more than the correct timing dimension, the spacer (in the pump housing bore) can be exchanged. See the SPACER PART NUMBER AND THICKNESS CHART.

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.

NOTE: The accessory drive shaft must be positioned correctly in relation to the engine crankshaft, before the fuel injection pump housing is installed.

Accessory Drive Shaft Timing

8S5417 Timing Fixture Plate,8S8375 Sleeve,8B7561 Step Plate,8S2264 Puller Group.

1. Remove the fuel injection pump housing and position the engine crankshaft so No. 1 piston is on compression stroke at top center (TC).

2. Install the 8S5417 Timing Fixture Plate on the rear face of the accessory drive housing, dowels aligned and bolts installed as illustrated.


TYPICAL 8S5417 TIMING FIXTURE PLATE INSTALLATION

NOTE: If the timing fixture plate can be installed, timing is correct. If it cannot be installed, proceed as follows:

3. Remove the small cover from the front of the timing gear housing. Remove the gear retaining nut and washer.

4. Loosen the gear from the accessory drive shaft.

5. Rotate the accessory drive shaft in the direction necessary to install the 8S5417 Timing Fixture Plate.

6. Install the conical washer, with the large diameter against the timing gear, and install the gear retaining nut.


LOOSENING GEAR
Tools required are the 8S5132 Puller Plate, 8S8375 Sleeve, 8S5133 Expansion Plug, 8S6470 Pressure Screw, 8B7561 Step Plate, two 3/8" NF Bolts 31/2 in. (88,9 mm) long and two 3/8" flat washers.


ROTATING THE ACCESSORY DRIVE SHAFT

7. Tighten the gear retaining nut to a torque of 100 ± 10 lb. ft. (13,8 ± 1,4 mkg) and remove the timing plate. The fuel injection pump camshaft will be in time with the engine crankshaft when the injection pump housing is installed on the engine.

Fuel Rack Setting

Rack Positioning Tool, Dial Indicator and Circuit Tester Method:

9S240 Rack Position Tool Group and4B9820 Wrench.

The 9S238 Rack Positioning Bracket 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, can provide most of the needed data to determine actual horsepower output and diagnose the cause for lack of power.


9S240 RACK POSITION TOOL GROUP
1-8S4627 Circuit Tester. 2-9S238 Rack Positioning Bracket Group. 3-9S215 Dial Indicator. 4-9S8521 Rod. 5-9S8518 Plug.

1. Refer to the RACK SETTING INFORMATION to obtain 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.

NOTE: The speed limiter will restrict rack travel until the engine is operating with proper oil pressure, or if engine is not operating the plunger is manually depressed.


DEPRESSING PLUNGER
4-9S8521 Rod (for manually depressing speed limiter plunger). 5-9S8518 Plug.

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

4. Install rack positioning bracket group and dial indicator, over the opening for fuel rack cover on front flange of accessory drive housing.

5. Place the spacer (6) over the rod in the bracket. Adjust the dial on the indicator to read zero when hole attachment (7) is against the rod and the rod is against the spacer.


DIAL INDICATOR ADJUSTED TO ZERO READING
6-Spacer. 7-Hole attachment.

6. Attach one end of the 8S4627 Circuit Tester to the brass screw terminal on the outside of the governor housing.

7. With the speed limiter depressed, move the governor control lever toward the fuel-on direction until the tester light comes on bright.

8. Slowly, move the governor control lever toward the shutoff position until the light goes out.

9. Now, again slowly move the governor control lever toward the fuel-on position, until the tester light just barely comes on (a dim light); rack collar is now just touching the stop bar. Rack setting dimension is read directly from the indicator.

10. To adjust the rack setting, loosen locknut (9) and with wrench (10), adjust screw (8) to obtain the correct rack setting dimension. Rack Travel can be read directly on the indicator.


ADJUSTING RACK SETTING
8-Adjusting screw. 9-Lock nut. 10-4B9820 Wrench.

NOTE: Turn screw (8) clockwise to decrease rack travel. Never adjust rack travel by adding or removing shims.

11. After the rack has been adjusted, tighten locknut (9) to a torque of 11 ± 1 lb. ft. (1,5 ± 0,14 mkg).

Rack Setting Gauge Method:

7S7113 Rack Setting Gauge.8S4627 Circuit Tester.FT960 Adapter Assembly.

Use a 7S7113 Rack Setting Gauge to check the fuel rack setting.

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.


GAUGE INSTALLED
1-7S7113 Rack Setting Gauge.

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

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

4. To adjust the rack, refer to the topic, RACK POSITIONING TOOL, DIAL INDICATOR AND CIRCUIT TESTER METHOD and follow Steps 6 through 11.

NOTE: If the fuel injection pump housing is removed from the engine, the fuel rack setting can be checked with 7S7113 Rack Setting Gauge, but FT960 Adapter Assembly must also be used.

Governor Adjustments

------ WARNING! ------

Only competent personnel should attempt to adjust the low and high idle RPM. The low and high idle RPM, and the rack setting dimensions for this engine, are listed in the RACK SETTING INFORMATION.

--------WARNING!------

Engine RPM should be checked with an accurate tachometer.


GOVERNOR ADJUSTMENTS
1-Cover. 2-Low idle adjusting screw. 3-Retainer holes (two). 4-High idle adjusting screw.

Low and high idle RPM can be adjusted by removing cover (1), 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. Retainer holes (3), 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 Setting

9S240 Rack Positioning Tool Group,4B9820 Wrench.

The fuel rack must be set correctly before setting the fuel ratio control.

1. Remove the rack cover from the front of the fuel injection pump housing, and cover (4) from the rear of the fuel ratio control.

2. Engage slot in cover (4) with cross-dowel in adjusting bolt and turn the adjusting bolt in as far as possible. This prevents the head of the bolt from limiting the travel of the fuel rack.


RETRACTING SPEED LIMITER PLUNGER
1-Governor control lever. 2-9S8518 Plug. 3-9S8521 Rod.

3. Install 9S238 Rack Positioning Bracket Group over the front end of the fuel rack and 9S215 Dial Indicator in the bracket.

4. Remove the plug from the bottom of the governor. Through opening in plug (2) use rod (3) to push in (retract) the speed limiter plunger.

5. Center the rack and set the dial indicator on zero. Remove the spacer.

6. With the speed limiter plunger held in, move governor control lever (1) to FULL LOAD position. Hold the lever in the FULL LOAD position while making the adjustment.

7. Turn adjusting bolt out with cover (4) until the correct dial indicator reading is obtained. The correct reading is listed in the RACK SETTING INFORMATION.

8. Turn cover (4) clockwise the amount necessary to align the bolt holes and install cover (4).


SETTING FUEL RATIO CONTROL
4-Cover.

9. Remove the 9S238 Rack Positioning Bracket Group, 9S215 Dial Indicator and install the rack cover.

10. Install the standard plug in place of plug (2).

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

With the above initial adjustment made, a further adjustment can be made while the engine is running, if necessary, to improve engine performance. To reduce exhaust smoke during acceleration, turn cover (4) out (less fuel) 1/2 turn at a time until satisfactory. When exhaust smoke is acceptable but acceleration is sluggish, turn cover (4) in (more fuel) 1/2 turn at a time until satisfactory.

NOTE: Some exhaust smoke is likely to appear at maximum acceleration. If acceleration is sluggish and full engine power seems to be lost, inspect the air line to the cover and the cover gasket for air leaks. If no air leaks are apparent, inspect the diaphragm. A damaged diaphragm will not allow the fuel rack to open completely, acceleration will be sluggish and full engine power cannot be obtained.

Governor Control Linkage Adjustment

1P2385 Protractor Assembly.

1. Place the governor control lever on the serrated governor control shaft at 90° dimension (1), from horizontal, when the governor is in LOW IDLE position.

2. Adjust the length of link assembly (4) to position cross shaft lever (5) at 120° dimension (2), from horizontal, when the governor is in LOW IDLE position.


GOVERNOR CONTROL LINKAGE
1-90° dimension (governor control lever). 2-120° dimension (governor linkage cross shaft lever).

3. Tighten the levers and link assembly locknuts when lever positions are correct.


MEASURING ANGLE OF LEVER
3-1P2385 Protractor Assembly. 4-Link assembly. 5-Governor linkage cross shaft lever.

Cooling System

The engine has a pressurized cooling system. Pressurizing the cooling system serves two purposes. First, it permits safe operation at coolant temperature higher than the normal boiling point; thereby, providing a margin of cooling for those intermittent peak loads. Secondly, it prevents cavitation in the water pump and reduces the possibility of air or steam pockets forming in the coolant passages.

Many times, overheating of the engine is caused by failure to make simple systematic inspections. Visual inspections should be made before instrumentation testing.

Visual Inspection

1 Check coolant level.

2 Inspect for leaks in the system.

3 Inspect the radiator fins. Be certain the air flow through the radiator is not restricted by trash or bent radiator fins.

4 Check fan belts.

5 Check for damaged fan blades.

6 Observe if there is any air or combustion gas in the cooling system.

7. Check to see that the radiator cap sealing surfaces are clean.

Testing Cooling System

Temperature Gauge

2F7112 Thermometer,3B7255 Bushing,3B7722 Bushing,9S9102 Thermistor Thermometer Group.

If overheating and loss of coolant is a problem, a pressure loss in the system could be the cause. If an overheating condition is indicated on the temperature gauge and loss of coolant is not evident, check the accuracy of the temperature gauge. Make this check by installing a 2F7112 Thermometer (using a 3B7255 Bushing and a 3B7722 Bushing).


THERMOMETER INSTALLATION

The accuracy of the temperature gauge can also be checked using the 9S9102 Thermistor Thermometer Group (2). Refer to the TOOL GUIDE. Special Instruction (GMG00450) explains the checking procedure.

------ WARNING! ------

Use CAUTION when working around an engine if it is running.

--------WARNING!------

Start the engine. Cover the radiator to reduce air flow and cooling. The instrument panel temperature gauge should be approximately the same as the test thermometer temperature.

Water Temperature Regulator

The opening temperature of the regulator (bench test in atmospheric pressure) should be approximately 165° F (73° C). The regulator should be fully open at approximately 180° F (82° C).

1. Remove the regulator from the cylinder head.

2. Suspend the regulator and a thermometer in a pan of water.

3. Apply heat to the pan and stir the water to maintain uniformity.

4. Observe the opening temperature of the regulator. If the regulator does not operate correctly, install a new regulator.

Pressurized Cooling System Relief Valve

Radiators equipped with either a removable threaded plug or fitting in the top tank can be pressurized to test the opening pressure of the relief valve.

There must be a pressure gauge and an adjustable valve, to control the pressure, in the line which is attached to the radiator top tank.

Slowly pressurize the radiator top tank. The highest pressure indicated on the gauge is the point the relief valve opens.


NOTICE

Do not exceed 16 PSI (1,1 kg/cm2). Higher pressure can damage components in the cooling system.


A leakage check can be performed by attaching a length of hose to the overflow device. Submerge the opposite end of the hose in a container of water. Pressurize the top tank to a pressure just below the relief valve opening pressure. A steady stream of bubbles from the submerged hose indicates a leak in the relief valve.

If the radiator cap and/or pressure relief valve is functioning properly and still the system will not hold pressure, a thorough inspection of the entire cooling system will be necessary. Correct any leaks detected by the inspection and repeat the pressure test.

Remember that temperature and pressure go hand-in-hand and neither one can be tested logically without considering the other. For example, the effect of pressurization and altitude on the boiling point of water is shown in the chart.

Lubrication System

Engine lubrication system problems are usually indicated by one of these symptoms:

EXCESSIVE OIL CONSUMPTIONLOW OIL PRESSUREHIGH OIL PRESSUREUNUSUAL BEARING WEAR

Excessive Oil Consumption

External Leaks

Check crankshaft seals for leakage at both ends of the engine, look for leaks around the oil pan gasket and all lubrication system connections. Check to see if oil is being blown from the crankcase breather. This can be caused by combustion gases leaking past pistons. Clogged crankcase breathers will contribute to high crankcase pressure and result in gasket and seal leaks.

Leaking turbocharger shaft seals (turbine end) will cause loss of oil through the exhaust gases. This condition is evidenced by oil at the exhaust outlet which may be referred to as "slobbering."

Internal Leakage Into Upper Cylinders

Upper cylinder oil leakage can be the cause of blue smoke. There are four possible routes for oil leakage into upper cylinders.

Oil can leak past the ring seals at the impeller end of the turbocharger shafts.

Leakage between worn guides and valves is also possible.

Worn or damaged piston rings or plugged oil return holes can cause oil to enter the upper cylinder. Incorrectly installed compression rings will cause oil to pump into the cylinders.

Excess oil usage can also be the result of oil viscosity being too low for prevailing conditions. Low oil viscosity can be caused by incorrect selection of oil weights, or engine overheating.

Low Oil Pressure

Oil Pressure Gauge

A defective oil pressure gauge may show low oil pressure.

Crankcase Lubricant Level

Oil level can be too low for oil pump suction bell pickup. Add oil if necessary.

Pump Malfunctions

The oil pump inlet screen can be restricting the suction side of the pump which results in loss of oil pressure. An air leak in the suction side of the pump will also cause loss of pressure. An oil pump bypass valve that is stuck in the open (unseated) position will not allow system pressure to build to maximum pressures. The oil pump gears can be worn sufficiently to cause a reduction in pump output.

Oil Filter and Bypass Valve

An oil filter bypass valve stuck in the closed position, with a restricted oil filter element, could cause low oil pressure. Install a new Caterpillar oil filter element, disassemble the bypass valve, clean the spring and plunger. Make certain the plunger moves freely in the valve before assembling the bypass valve.

Excessive Clearance in Engine Bearings or Open System

Worn components with extreme bearing clearances can cause engine oil pressure to be abnormally low. Any open, broken, or disconnected oil lines or passages will cause loss of oil pressure. Check gallery and crankshaft plugs to be sure they are in place.

Oil Cooler and Bypass Valve

Check the oil cooler oil passages for sludge. A clogged oil cooler with a stuck cooler bypass valve will be accompanied by high engine operating oil temperatures. Oil pressure will usually not lower due to sludge deposits alone. The cooler bypass valve must be stuck closed, or nearly so, along with clogged oil cooler to lower the oil pressure.

High Oil Pressure

This condition will occur when an oil pump bypass valve sticks in the closed position and the full pump volume is directed to the engine bearings.

Unusual Bearing Wear

Single components of the engine showing bearing wear at unusually frequent service intervals can be the result of clogged, restricted or broken oil passages. If the oil pressure gauge shows adequate pressure yet a component shows bearing wear, check the branch supply line to that component.

Turbocharger Lubrication Valve

When the oil pressure gauge indicates adequate oil pressure and bearing failure or wear occurs in the turbocharger, check the turbocharger lubrication valve operation. The valve can be stuck and unfiltered oil is lubricating the turbocharger.

Starting And Charging Systems

Most of the electrical system testing can be performed on the vehicle. An "on-vehicle" test that indicates a defective component usually requires component removal for further testing.

1 -Battery must be at least 75% (1.240 Sp. Gr.) full charged and properly secured in the carrier. The carrier must not place excessive physical strain on the battery.

2 -Cables between the battery, starter and engine ground must be of recommended wire size. Wires and cables must be free of corrosion with cable supporting clamps to reduce strain on battery posts.

3 -Leads, junctions, switches and panel instruments that are directly related to the charging circuit must be good enough to provide proper circuit control.

4 -Inspect the crankshaft pulley, charging unit pulleys and drive belts to be sure they are free of grease and oil and are capable of driving the charging unit load.

Battery

9S1990 BATTERY CHARGER TESTER.

The storage battery circuit represents a continuous, although variable, electrical load to the charging unit. If the circuit, positive or negative is opened or broken while the charging unit is charging, the loss of the battery load will result in the charging voltage rising to unsafe levels.

High voltage will damage the charging unit and regulator and may damage other electrical components or instruments.

NEVER DISCONNECT ANY CHARGING UNIT CIRCUIT OR BATTERY CIRCUIT CABLE FROM BATTERY WHEN THE CHARGING UNIT IS PRODUCING A CHARGE.

A load test should be made on a battery that discharges very rapidly when in use. To do this apply a resistance of three times the ampere/hour rating of the battery across the battery main terminals. Allow the resistance to discharge the battery for 15 seconds and immediately test the battery voltage. A 12 volt battery in good condition will test 9 volts.

The instructions included with the 9S1990 Battery Charger Tester completely covers the battery testing subject.

Starting System

Use a D.C. voltmeter to locate starting system components which do not function.

Turn the disconnect switch ON. Attach one voltmeter lead to the starter solenoid terminal connected to both a cable and a small wire. Ground the other voltmeter lead. No voltmeter reading indicates a defective disconnect switch. A voltmeter reading of battery voltage indicates further testing is necessary.

Turn the HEAT-START switch to the START position. Starting motor solenoid operation is audible as the starter motor pinion engages with the ring gear on the engine flywheel. The solenoid operation should also close the electric circuit to the motor. Attach one voltmeter lead to the solenoid terminal that is connected to the motor. Ground the other lead. Turn the HEAT-START switch to START and observe the voltmeter. A battery voltage reading indicates the malfunction is in the motor. It must be removed for further testing. No voltmeter reading indicates that the solenoid contacts do not close and the solenoid must be repaired or the starter pinion clearance should be adjusted.

A starting motor solenoid that will not operate may not be receiving battery current. Attach one lead of the voltmeter to the solenoid battery cable connection. Ground the other lead. No voltmeter reading indicates a defective disconnect switch. A voltmeter reading indicates further testing is necessary.

Continue the test by attaching one voltmeter lead to the starting motor solenoid small wire terminal and the other lead to ground. Observe the voltmeter and turn the HEAT-START switch to START. A voltmeter reading indicates that the malfunction is in the solenoid. No voltmeter reading indicates that either the circuit breaker is defective or the HEAT-START switch does not close when turned to the START position.

Attach one lead of the voltmeter to the HEAT-START switch battery wire terminal and ground the other lead. A voltmeter reading indicates a defective switch. No voltmeter reading indicates the circuit breaker points are open. If the circuit breaker reset button will not close the points the circuit breaker is defective.

A starting motor that operates too slow can be overloaded by excessive mechanical friction within the engine being started. Slow starting motor operation can also be caused by shorts, loose connections and/or excessive dirt within the motor.

Glow plugs can be checked with an ammeter. Disconnect the wire lead from the glow plug terminal on the HEAT-START switch. Install an ammeter, in series, between the disconnected lead and the terminal on the switch. Observe the ammeter with the HEAT-START switch turned to the HEAT position. Each glow plug draws approximately 10 amperes. The ampere draw of one glow plug multiplied by the number of engine cylinders will be the total ampere draw of the glow plugs in the engine. A low reading is an indication of one or more defective glow plugs. Disconnect one glow plug lead at a time and observe the ammeter with the switch turned to HEAT. The disconnected glow plug that does not change the ammeter reading is the defective glow plug.

When no ammeter reading is obtained, test the HEAT-START switch. Attach one lead of the voltmeter to the glow plug wire terminal on the HEAT-START switch and the other lead to the ground. Observe the voltmeter and turn the switch to HEAT. No voltage indicates that the HEAT-START switch is defective.

Pinion Clearance Adjustment (Delco-Remy)

Whenever the solenoid is installed, the pinion clearance should be adjusted. The adjustment should be made with the starting motor removed.

Bench test and adjust the pinion clearance at installation of solenoid as follows:

1. Install the solenoid without connector (1) from the MOTOR 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. MOMENTARILY flash a jumper wire from the solenoid terminal marked MOTOR to the ground terminal. The pinion will shift into cranking position and will remain there until the battery is disconnected.

5. Push pinion towards commutator end to eliminate free movement.

6. Pinion clearance (6) is .36 in. (9,14 mm).

7. Adjust clearance by removing plug and turning shaft nut (4).


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


PINION CLEARANCE ADJUSTMENT (Delco-Remy)
4-Shaft nut. 5-Pinion. 6-Pinion clearance.

Charging System

The condition and state of charge of the battery at each regular inspection will indicate if the charging system is operating efficiently. An adjustment is necessary either when the battery is always in a low state of charge or an excessive amount of water must be added to the battery (more than one ounce of water per cell per week or per every 50 service hours).

Charging unit and voltage regulator should be tested on the vehicle when possible, using wiring and accessories that are a permanent part of the system. Bench testing will provide the technician with an operational test of the charging unit or voltage regulator. Pre-repair testing will advise the depth of needed repairs. Final testing will prove the units are restored to their original operating efficiency.

Alternator Regulator (Delco)

When an alternator is either overcharging or undercharging the battery, the alternator charging rate can be adjusted. Remove the hollow head screw from the cover of the alternator regulator and use a screwdriver to turn the inside adjustment. Turn the adjustment toward the "+" to increase or toward the "-" to decrease the alternator charging rate.

Basic Block

Cylinder Liner Projection

1P2394 Adapter PlateTwo 3H465 PlatesCrossbar (from 8B7548 Push Puller)Two 5/8"-11 NC bolts, 5.5 in. (118,7 mm) longTwo 4B4281 Washers1P5510 Liner Projection Tool Group

Check liner height projection as follows:

1. Make certain that top of block and cylinder liner flange are clean and free of burrs.

2. Place adapter plate (4) in the cylinder liner. Center crossbar (2) on the adapter plate. Using bolts (1), washers (3) and plates (5), secure the crossbar to the cylinder block as shown. Tighten bolts (1) alternately, in four steps to; 5 lb. ft. (0,7 mkg), 15 lb.ft. (2,0 mkg), 25 lb. ft. (3,5 mkg) and finally to 50 lb. ft. (6,9 mkg). Distance from bottom edge of crossbar, to top of cylinder block, must be the same on both sides of the cylinder liner.


CHECKING LINER PROJECTION
1-Bolts (two). 2-Crossbar. 3-4B4281 Washers (two). 4-1P2394 Adapter Plate. 5-3H465 Plates (two).


SETTING INDICATOR ON ZERO
6-1P2402 Block. 7-1P2403 Dial Indicator. 8-1P5507 Gauge.

3. Install 1P2403 Dial Indicator (7) in 1P2402 Block (6) and use the back of 1P5507 Gauge (8) to "zero" the dial indicator.

4. Measure the liner projection in four places around the liner. Liner projection must be .0020 to .0056 in. (0,051 to 0,142 mm) and the four measurements should not vary more than .002 in. (0.05 mm). The average liner projection between adjacent cylinders must not vary more than .002 in. (0.05 mm).

Connecting Rods And Pistons

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

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

Tighten connecting rod bolt nuts in the following Step sequence.

Flywheel

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.

Crankshaft

Heat crankshaft gear to 600° F. (315° C.) maximum before installing on crankshaft. Install seal so spring-loaded lip faces centerline of cylinder block.

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