Introduction

NOTE: For Specifications with illustrations, make reference to SPECIFICATIONS FOR 5.4" BORE 60° V8 VEHICULAR ENGINE, Form No. SENR7205. If the Specifications in Form SENR7205 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 in the book with the latest date.

Fuel System

FUEL SYSTEM SCHEMATIC
1. Fuel transfer pump. 2. Check valve. 3. Fuel injection pump. 4. Fuel filter. 5. Reservoir. 6. Fuel supply line. 7. Electric priming pump. 8. Fuel return line to tank. 9. Fuel filters. 10. Fuel filter bleed. 11. Injection pump bleed. 12. Bypass valve. 13. Switch.

NOTE: The fuel system shown is for the earlier engines. Even though some components on the later engines are not located the same as on the earlier engines, this schematic still applies. The 600 Series Tractors have a manually operated priming pump.

Fuel is drawn from the fuel tank through the fuel supply line and fuel filter by the transfer pump. This pump is mounted on the fuel injection pump housing and is driven by a shaft connected to the fuel injection pump camshaft.

A bypass valve, at the inlet side of the fuel filter, assures adequate pressure for the fuel system and allows excess fuel to be bypassed back to the fuel tank through a fuel return line.

A fuel priming pump is used to fill the filter case, pressurize the fuel and assure that the system is free of air prior to starting the engine. A system of check valves allows fuel to be pumped past the fuel transfer pump when the priming pump is in use. As the filter and fuel injection pump passages are being filled with fuel from the priming pump, the fuel filter bleed on the filter housing can be opened to allow air to escape. The injection pump bleed valve can be used to allow any entrained air to escape from the individual fuel pumps and eliminate the need for loosening fuel line connections at the individual fuel pumps.

Individual fuel injection lines carry fuel from the pumps to each cylinder. One section of line connects between the fuel injection pump and an adapter on the inward portion of the camshaft housing. Another section of line on the inside of the camshaft housing connects between the adapter and the top of the precombustion chamber.

The fuel pump camshaft is driven by gears located inside a cover at the rear of the engine. An adjustable drive gear at the rear of the engine vee, drives a speed sensing, variable timing unit which in turn is coupled to the fuel pump camshaft through a sliding spline. This variable timing unit automatically provides retarded timing for easier starting and smooth low rpm operation. It will also advance timing as engine rpm increases to provide optimum engine operating efficiency.

Fuel Injection Pump

Fuel enters the fuel injection pump housing through passage (6) and enters the fuel injection pump body through the inlet port (2). The injection pump plungers (5) and the lifters (11) are lifted by the cam lobes (12) on the camshaft and always make a full stroke. The lifters are held against the cam lobes by the springs (3). Each pump measures the amount of fuel to be injected into its respective cylinder and forces it out the fuel injection nozzle.

The amount of fuel pumped each stroke is varied by turning the plunger in the barrel. The plunger is turned by the governor action through the fuel rack (8) which turns the gear segment (10) on the bottom of the pump plunger. Passage (4) provides fuel to lubricate the pump plunger and passage (7) allows air to be bled from the system through the valve on top of the fuel filter case.

FUEL INJECTION PUMP
1. Check valve. 2. Inlet port. 3. Spring. 4. Lubrication passage (fuel). 5. Pump plunger. 6. Fuel passage. 7. Bleed passage. 8. Fuel rack. 9. Lubrication passage (oil). 10. Gear segment. 11. Pump Lifter. 12. Camshaft lobe.

Fuel Injection Valve

FUEL INJECTION VALVE CROSS SECTION
1. Fuel line assembly. 2. Seal. 3. Body. 4. Nut. 5. Seal. 6. Nozzle assembly. 7. Glow plug. 8. Precombustion chamber.

Fuel, under high pressure from the injection pumps, is transferred through the injection lines to the injection valves. As high pressure fuel enters the nozzle assembly, the check valve within the nozzle opens and permits the fuel to enter the precombustion chamber. The injection valve provides the proper spray pattern.

Speed Sensing, Variable Timing Unit

The variable timing unit, couples the fuel injection pump camshaft to the engine rear timing gears. The variable timing unit advances the timing as engine rpm increases.

On earlier engines the timing advances from 11° BTC at low idle to 19° BTC at high idle. On later engines the timing advances from 8° BTC at low idle to 19° BTC at high idle.

LOW RPM POSITION
1. Power piston. 2. Power piston cavity. 3. Control valve spring. 4. Power piston return spring. 5. Oil inlet passage. 6. Drain port. 7. Control valve. 8. Flyweights. 9. Shaft assembly.

During engine low rpm operation, the flyweight force is not sufficient to overcome the force of control valve spring (3) and move control valve (7) to the closed position. Oil merely flows through the power piston cavity (2).

HIGH RPM POSITION
1. Power piston. 2. Power piston cavity. 3. Control valve spring. 4. Power piston return spring. 5. Oil inlet passage. 6. Drain port. 7. Control valve. 8. Flyweights. 9. Shaft assembly.

As the engine rpm increases, flyweights (8) overcome the force of control valve spring (3) and move control valve (7) to the closed position, blocking the oil drain port (6). Pressurized oil, trapped in power piston cavity (2), overcomes the force of spring (4) and moves power piston (1) outward. This causes the fuel injection pump camshaft to index slightly ahead of the shaft portion (9) of the variable timing unit. Any outward movement of the power piston increases the force on the control valve spring. This tends to reopen the control valve, letting oil escape from the power piston cavity. As oil begins flowing from the cavity again, return spring (4) moves the power piston inward.

At any given rpm, a balance is reached between the flyweight force and the control valve spring force. The resultant position of control valve (7) will tend to maintain proper pressure behind the power piston. The greater the rpm, the smaller the drain port opening, and the further outward the power piston is forced.

As the power piston is moved outward, the angular relationship of the ends of the drive unit change. As the power piston moves forward in the internal helical spline, the fuel injection pump timing advances.

The gear teeth on shaft assembly (9) drive the governor drive pinion.

Governor

Oil pump gear (14), part of shaft (19), provides immediate pressure oil for the governor. A sump in body assembly (15) provides immediate supply for the pump. A bypass valve, in the body assembly, maintains correct oil pressure.

When the engine is operating, pressure oil from the pump is directed through passage (11) in cylinder (10), to a space around sleeve (13) and through an oil passage in piston (12) to a groove around valve (9). When revolving weights (7) slow down (occurring when engine load increases), the weights move in, allowing governor spring (6) to move valve (9) down. When the valve moves down, the oil passage in piston (12) opens to pressure oil in the groove around valve (9). Pressure oil is now at the large area end of piston (12) and pushes the piston, valve (9) and shaft (16) down. Shaft (16) pushes lever (18), moving fuel rack (21) forward thus increasing the amount of fuel to the engine.

With more fuel, engine rpm increases until the revolving weights again rotate fast enough to balance the force of the governor spring. The passage in piston (12) will be between the oil pressure groove and the oil drain groove in valve (9). The movement of piston (12), valve (9), shaft (16), lever (18) and fuel rack (21) stops and engine rpm is the same as before. When engine load decreases, revolving weights (7) speed up and toes on the weights move valve (9) upward opening oil passage in piston (12) to the drain groove around valve (9). Oil pressure between sleeve (13) and piston (12) pushes the piston, valve (9) and shaft (16) upward which moves fuel rack (21) to decrease the amount of fuel to the engine and the rpm of the engine (and revolving weights) decreases. When revolving weight force again balances governor spring force, the rpm of the engine is the same as before.

GOVERNOR CROSS-SECTION
1. Adjusting screw. 2. Collar. 3. Bolt. 4. Lever assembly. 5. Seat assembly. 6. Governor Spring. 7. Flyweights. 8. Seat. 9. Valve. 10. Cylinder. 11. Oil passage. 12. Piston and valve assembly. 13. Sleeve. 14. Gear. 15. Body assembly. 16. Shaft. 17. Shaft assembly. 18. Lever. 19. Quill shaft. 20. Drive pinion. 21. Fuel rack. A. Speed limiter.

The engine is stopped by pulling up on the accelerator pedal.

An oil passage through the center of valve (9) has a small oil outlet near the top end of the valve to lubricate a thrust bearing under seat (8). The bearing surface of flyweight assembly (7) drive gear, receives lubricating oil from the oil around sleeve (13), through an opening in cylinder (10).

Governor action will change if there is a loss in lubricating oil pressure; however, the governor still offers protection against engine overspeeding because the flyweights are mechanically connected to the fuel rack. The mechanical connections make it possible to move the fuel rack to the SHUTOFF position by using the controls normally used to stop the engine.

When the engine is started, speed limiter plunger (A) restricts the movement of the governor control linkage. When operating oil pressure is reached, the plunger in the speed limiter retracts and the governor control can be moved to the HIGH IDLE position.

Fuel Ratio Control

The fuel ratio control coordinates the movement of the fuel rack with the amount of air available in the inlet manifold. The control keeps the fuel to air ratio more efficient, thus minimizing exhaust smoke.

A manually operated override lever (1) is provided to allow unrestricted rack movement during cold starts. After the engine starts, the override automatically resets in the RUN position.

Collar (6) mechanically connects to the fuel rack. The head of bolt assembly (7) latches through a slot in collar (6). An air line connects the chamber above diaphragm (5), with the air in the engine inlet manifold.

FUEL RATIO CONTROL CROSS SECTION
1. Lever. 2. Housing. 3. Spring. 4. Spring. 5. Diaphragm. 6. Collar. 7. Bolt assembly.

When the operator moves the governor control to increase engine rpm, the governor spring moves collar (6) down until it contacts the head of bolt assembly (7). The bolt assembly restricts the movement of the bolt and collar until spring (3) and the turbocharger boost of air pressure in housing (2) forces diaphragm (5), spring (4) and bolt assembly (7) to relieve the bolt head restriction to bolt and collar (6). This allows the fuel rack to move to increase the fuel as turbocharger air pressure (boost) increases with the increase in engine rpm.

Fuel Ratio Control (Hydraulic Activated)

The hydraulic activated fuel ratio control automatically causes a restriction to the amount of travel of the rack in the "fuel on" direction, until the air pressure in the inlet manifold is high enough to give complete combustion. The fuel ratio control keeps engine performance high.

FUEL RATIO CONTROL (HYDRAULIC ACTIVATED)
1. Valve. 2. Oil inlet passage. 3. Passage for inlet air pressure. 4. Oil outlet passage. 5. Large oil passage. 6. Oil drain. 7. Spring. 8. Diaphragm. 9. Valve.

The hydraulic activated fuel ratio control has two valves (1) and (9). Engine oil pressure works against valve (1) to control the movement of the fuel rack. Air pressure from the inlet manifold works against diaphragm (8) to move valve (9) to control oil pressure against valve (1).

When the engine is stopped, there is no pressure on either valve. Spring (7) moves both valves to the ends of their travel. In this position, the fuel rack travel is not restricted. Also in this position, an oil outlet passage (4) is open to let oil away from valve (1).

When the engine is started, the open oil outlet passage (4) prevents oil pressure against valve (1) until air pressure from the inlet manifold is high enough to move valve (9) to close the large oil passage (5). Engine oil pressure then works against valve (1) to move this valve into its operating position. The control will operate until the engine is stopped.

When the governor control is moved toward the full load position with the engine running, the head on the stem of valve (1) will cause a restriction to the travel of the fuel rack, until the air pressure in the inlet manifold has an increase. As there is an increase in the air pressure in the inlet manifold, this pressure works against diaphragm (8) to cause valve (9) to move to the left. The large oil passage (5) becomes open to let oil pressure away from valve (1), toward spring (7), and out to drain (6). As there is a decrease in oil pressure, valve (1) moves to the left to let the fuel rack open at a rate equal to (the same as) the air available for combustion.

Fuel Priming Pump

An electric fuel priming pump is provided for truck engines. When the glow plugs are activated, the priming pump operates. A switch located on the fuel filter housing can be used to operate the fuel priming pump without activating the glow plugs.

Air Induction And Exhaust System

AIR INDUCTION AND EXHAUST SYSTEM (SCHEMATIC)
1. Flywheel. 2. Exhaust manifold (left bank). 3. Turbocharger. 4. Intake manifolds. 5. Air inlet to turbocharger (from the air cleaner). 6. Engine exhaust (from turbocharger). 7. Exhaust manifold (right bank). Each cylinder of the engine is numbered 1 through 8.

The turbocharger is between the cylinder banks at the front of the engine. It is driven by exhaust gas, from the engine cylinders, that goes through exhaust manifolds (2) and (7).

Exhaust manifolds (2) and (7) have one section to a cylinder. These are interchangeable between banks. Studs and nuts are used to secure the manifold sections to the cylinder heads.

Inlet air for the engine is drawn through the air cleaner by the turbocharger. From turbocharger (3), air is forced directly through intake manifolds (4) into the combustion area of each cylinder.

The intake manifolds (4) have two sections on each bank. The sections are interchangeable between banks.

There are four valves (two intake and two exhaust) for each cylinder. The valves are actuated by overhead camshafts and forked rocker arm assemblies, located in the housing on top of the cylinder heads.

Exhaust gases leave each cylinder through two exhaust valve ports. After passing through the turbine side of the turbocharger, the exhaust exits through exhaust outlet (6).

Turbocharger

All the exhaust gases from the diesel engine pass through the turbocharger.

The exhaust gases enter the turbine housing (10) and are directed through the blades of a turbine wheel (9), causing the turbine wheel and a compressor wheel (4) to rotate.

Filtered air from the air cleaners is drawn through the compressor housing air inlet (1) by the rotating compressor wheel. The air is compressed by action of the compressor wheel and forced to the inlet manifold of the engine.

TURBOCHARGER (Typical Illustration)
1. Air inlet. 2. Compressor housing. 3. Nut. 4. Compressor wheel. 5. Thrust plate. 6. Center housing. 7. Lubrication inlet port. 8. Shroud. 9. Turbine wheel and shaft. 10. Turbine housing. 11. Exhaust outlet. 12. Spacer. 13. Ring. 14. Seal. 15. Collar. 16. Lubrication outlet port. 17. Ring. 18. Bearing. 19. Ring.

When engine load increases, more fuel is injected into the engine cylinders. The volume of exhaust gas increases causing the turbocharger turbine wheel and compressor impeller to rotate faster. The increased rpm of the impeller increases the quantity of inlet air. As the turbocharger provides additional inlet air, more fuel can be burned; hence more horsepower derived from the engine.

Maximum rpm of the turbocharger is controlled by the rack setting, the high idle speed setting and the height above sea level at which the engine is operated.

Show/hide table

If the high idle rpm or the rack setting is higher than given in the RACK SETTING INFORMATION (for the height above sea level at which the engine is operated), there can be damage to engine or turbocharger parts.

The bearings for the turbocharger use engine oil under pressure for lubrication. The oil comes in through the inlet port (7) and goes through passages in the center section for lubrication of the bearings. Oil from the turbocharger goes out through the outlet port (16) in the bottom of the center section and goes back to the engine lubricating system.

The fuel rack adjustment is done at the factory for a specific engine application. The governor housing and turbocharger are sealed to prevent changes in the adjustment of the rack and the high idle speed setting.

Cylinder Heads, Valves And Camshafts

Cylinder Heads and Valves

This is a four stroke cycle engine; i.e., four separate piston strokes are required to complete the firing of one cylinder.

There are four in-head valves for each cylinder; two intake valves and two exhaust valves.

The in-head valves are perpendicular to the bottom face of the cylinder head. The exhaust valves and ports are located toward the outside of the engine. The intake valves are on the inside, toward the vee.

A primary feature of the cylinder head is parallel porting. This provides individual porting for each of the two exhaust valves and the two intake valves. This permits unrestricted flow of air and exhaust gasses; resulting in maximum breathing capability and efficiency.

Valves, valve seats, seating springs and rotators are all part of the cylinder head assembly. The valve seats are pressed into the cylinder head and are replaceable.

Valve rotators add much to valve life. Each valve is rotated approximately three degrees on every lift; thus minimizing pitting of the valve faces and valve seats. The rotation also causes a wiping action to remove carbon deposits from the valve seat.

Rocker Arms

Valve action is accomplished through a roller-rocker arm arrangement. The forked rocker arm (2), located in the camshaft housing, pivots on a shaft (4) at one end and depresses two valves at the other end through adjusting screws. A roller (5), supported by a pin near the center of the rocker arm, rides on the camshaft (1) lobe. Thus, one camshaft lobe actuates the forked rocker arm and opens two valves simultaneously.

Valve adjustment can be quickly and accurately accomplished with a screwdriver. No thickness gauge is required. Turn the adjusting screw (3) down to remove all clearance, then back off to the required setting.

ROCKER ARM
1. Camshaft. 2. Rocker arm. 3. Adjusting screw. 4. Pivot shaft. 5. Roller. 6. Spring. 7. Valve.

Camshafts

This engine uses two overhead camshafts in each cylinder bank. The inner camshaft in each bank actuates all the intake valves and the other camshaft actuates all the exhaust valves.

The camshafts are driven from both ends of the engine. The right bank camshafts are driven by the rear gear train. On the left bank, the inlet camshaft drives the exhaust camshaft. On the right bank, the exhaust camshaft (F) drives the inlet camshaft (E).

CYLINDER BLOCK
A. Flywheel end. B. Left side. C. Front end. D. Right side. E. Inlet camshaft. F. Exhaust camshaft.

The camshaft journals are supported in integrally cast webs of the camshaft housings. Pressure lubrication to the camshaft journals is supplied from the cylinder block through the cylinder head, and into drilled passages in the camshaft housing.

A crankcase breather is mounted on the front of the right bank camshaft cover. The element is removable for cleaning. A fumes disposal tube carries the crankcase fumes to a level below the engine.

Lubrication System

LUBRICATION SYSTEM SCHEMATIC
1. Oil passage to left bank valve train. 2. To governor and fuel injection pump. 3. Main oil manifold. 4. Oil passage to right bank valve train. 5. Turbocharger. 6. Oil passage to rear gear train. 7. Turbocharger lubrication valve. 8. Oil passage to front gear train. 9. Oil passage to main bearings, rod bearings and piston cooling jets. 10. Oil cooler. 11. Scavenge pump. 12. Oil pump. 13. Bypass valve. 14. Oil cooler bypass. 15. Oil filter bypass valve. 16. Oil filter.

NOTE: The lubrication system shown is for the earlier engines. Even though some components on the later engines are not located the same as on the earlier engines, this schematic still applies.

Under normal operating conditions, oil flow is as follows: Oil from the sump is delivered by the oil pump, through the oil cooler and filters, to the front mounted timing gears, rear mounted timing gears, crankshaft main bearings, connecting rod bearings, piston cooling jets, governor and fuel injection pump housing, right and left bank valve mechanisms, and the turbocharger.

A bypass valve, located in the oil pump body, limits the maximum pressure of oil from the pump.

A turbocharger lubrication valve is located at the front of the engine. When the engine is started, the flow of oil through the cooler and filters is momentarily restricted. The lubrication valve opens and oil flows directly to the turbocharger. When pressure through the cooler and filters is equalized, the turbocharger lubrication valve closes to provide filtered oil to the turbocharger.

An oil filter bypass valve and an oil cooler bypass valve are located in the oil filter base.

On cold starts, the oil cooler and filter bypass valves open, eliminating the oil cooler and filter restrictions. Oil from the pump is directed past the bypass valves and directly to the engine components.

As oil temperature increases, the bypass valves close. Oil is then forced to flow through the oil cooler and filter. Unless the oil filters are restricted, or oil viscosity is extremely high, only filtered oil is furnished to the engine components. If the oil filters become restricted, the oil filter bypass valve opens, and allows oil to flow directly to engine components.

The governor lubrication system includes an oil pump within the governor. Governor oil collects at the bottom of the governor housing and overflows into the fuel pump housing through a standpipe. This reservoir supplies oil to the governor oil pump located in the plate assembly between the governor housing and the fuel pump housing. This pump supplies immediate oil pressure to the servo mechanism to obtain quick response from the governor when the engine is started.

The fuel injection pump housing also contains an oil manifold which supplies oil to the camshaft bearings and the lifter rollers. The lifter rollers and camshaft lobes receive oil each time a lifter moves up and uncovers an oil hole. Oil drains from the fuel pump housing to the cylinder block.

FUEL INJECTION PUMP AND GOVERNOR LUBRICATION SYSTEM
1. Speed limiter. 2. Bypass valve. 3. Governor oil pump oil supply. 4. Oil supply from cylinder block. 5. Fuel injection pump oil manifold. 6. Oil supply to speed sensing-variable timing unit. 7. and 8. Oil return to cylinder block.

Cooling System - (Earlier Engines)

ENGINE COOLING SYSTEM SCHEMATIC - EARLIER ENGINES (Water Temperature Regulators Open)
1. Radiator core. 2. Bypass line (top tank to water pump). 3. Expansion tank. 4. Shunt line, (top tank to water pump). 5. Vent line (top tank to expansion tank). 6. Coolant return line. 7. Top tank. 8. Line (external line to cylinder block). 9. External line, (water pump to engine oil cooler). 10. Engine oil cooler. 11. Brake oil cooler. 12. Line (engine oil cooler to cylinder block). 13. Line (engine oil cooler to air compressor). 14. Air compressor. 15. Line, (air compressor to coolant crossover line). 16. Right cylinder head. 17. Cylinder block. 18. Left cylinder head. 19. Bottom tank. 20. Water temperature regulators. 21. Valve (fan drive oil control). 22. Water pump. 23. Torque converter oil cooler. 24. Coolant crossover line.

The radiator is constructed with a top tank (7), core (1) and expansion tank (3). Vent line (5) connects top tank (7) and expansion tank (3). The expansion tank has a shunt line (4) which connects to the water pump inlet. The shunt system maintains a positive, static head of coolant at the pump inlet to prevent cavitation under all operating conditions. When filling the cooling system, coolant from expansion tank (3) flows through shunt line (4) to water pump inlet and fills the cooling system from the bottom. By filling the system from the bottom, air in the system is forced out through top tank (7), through vent line (5) into expansion tank (3).

Water temperature regulators (20) are located at the inlet to water pump (22). The inlet-regulated cooling system maintains positive coolant temperature control with decreased engine warm up time.

When water temperature regulators (20) are closed, coolant is circulated through the cylinder block and cylinder heads and back to water pump (22) by way of bypass line (2). When water temperature regulators (20) are open, the bypass flow is restricted and the coolant flows through radiator core (1) and bottom tank (19) and returns to water pump (22). Without the water temperature regulators installed, the coolant will continually bypass the radiator and overheating will result.

The centrifugal-type water pump (22) is mounted on the left front of the engine and is gear driven. The water pump has two outlets.

Coolant from the upper outlet of water pump (22) flows through external line (9) to engine oil cooler (10). A small amount of coolant flows from external line (9), through line (8) to cylinder block (17). The coolant flows through engine oil cooler (10) and line (12) to cylinder block (17). The coolant flows through the right side of cylinder block (17) and right cylinder head (16). The coolant flows out the rear of right cylinder head (16) through coolant crossover line (24) to brake oil cooler (11) located above the engine. The coolant flows through brake oil cooler (11) to coolant return line (6). Coolant return line (6) delivers the coolant to top tank (7).

Air compressor (14) receives its coolant through line (13). Coolant from air compressor (14) flows through line (15) to coolant crossover line (24) which delivers the coolant to brake oil cooler (11).

Coolant from lower outlet of water pump (22) passes through torque converter oil cooler (23) to the left side of cylinder block (17). Coolant delivered from torque converter oil cooler (23) to left side of cylinder block, flows through cylinder block and left cylinder head (18). The coolant flows out of the rear of left cylinder head (18), through crossover line (24) to brake oil cooler (11).

If the coolant has not attained operating temperature, water temperature regulators (20) will be closed. The coolant will then flow through top tank (7), bypassing radiator core (1) and flows through bypass line (2) to water pump inlet.

When the coolant temperature reaches normal operating level, water temperature regulators (20) will open and allow the coolant to flow through radiator core (1) and out of bottom tank (19) to water pump inlet.

The fan drive is a fluid coupling. Oil quantity in the coupling is controlled by valve (21) mounted on side of water pump inlet housing. Valve (21) senses the temperature of the coolant in the radiator bottom tank. Temperature of coolant controls the opening of fan drive control valve. The hotter the coolant, the more the valve opens, thus the amount of oil to fan drive fluid coupling is increased, increasing the speed of the fan. A drain line at the bottom of the fan drive housing, returns the oil to the engine crankcase.

Also included in the cooling system is an air-to-air aftercooler. The aftercooler core is mounted in front of the radiator core. The air discharge from the turbocharger connects to the top of the aftercooler. Air flows downward through the aftercooler core, out the bottom of the aftercooler to the air inlet manifolds of the engine.

Cooling System - (Later Engines)

ENGINE COOLING SYSTEM SCHEMATIC - LATER ENGINES (Water Temperature Regulators Open)
1. Radiator core. 2. Bypass line (top tank to water pump). 3. Expansion tank. 4. Shunt line (top tank to water pump). 5. Vent line (top tank to expansion tank). 6. Coolant return line. 7. Top tank. 8. Line (external line to cylinder block). 9. External line (water pump to engine oil cooler). 10. Engine oil cooler. 11. Line. 12. Line (engine oil cooler to cylinder block). 13. Line (engine oil cooler to air compressor). 14. Air compressor. 15. Line (air compressor to right cylinder head). 16. Right cylinder head. 17. Cylinder block. 18. Left cylinder head. 19. Bottom tank. 20. Water temperature regulators. 21. Valve (fan drive oil control). 22. Water pump. 23. Brake oil cooler. 24. Torque converter oil cooler.

The radiator is constructed with a top tank (7), core (1) and expansion tank (3). Vent line (5) connects radiator top tank (7) and expansion tank (3). The expansion tank has a shunt line (4) which connects to the water pump inlet. The shunt system maintains a positive, static head of coolant at the pump inlet to prevent cavitation under all operating conditions. When filling the cooling system, coolant from expansion tank (3) flows through the shunt line (4) to water pump inlet and fills the cooling system from the bottom. By filling the system from the bottom, air in the system is forced out through top tank (7), through vent line (5) into expansion tank (3).

Water temperature regulators (20) are located at the inlet to the water pump (22). The inlet-regulated cooling system maintains positive coolant temperature control with decreased engine warm up time.

When water temperature regulators (20) are closed, coolant is circulated through the cylinder block and cylinder heads and back to water pump (22) by way of bypass line (2). When the water temperature regulators (20) are open, the bypass flow is restricted and the coolant flows through radiator core (1) and bottom tank (19) and returns to water pump (22). Without the water temperature regulators installed, the coolant will continually bypass the radiator and overheating will result.

The centrifugal-type water pump (22) is mounted on the left front of the engine and is gear driven. The water pump has two outlets.

Coolant from the upper outlet of water pump (22) flows through external line (9) to engine oil cooler (10). A small amount of coolant flows from external line (9), through line (8) to cylinder block (17). The coolant flows through engine oil cooler (10) and line (12) to cylinder block (17). The coolant flows through the right side of cylinder block (17) and right cylinder head (16) to coolant return line (6). Coolant return line (6) delivers the coolant to top tank (7).

Air compressor (14) receives its coolant through line (13). Coolant from air compressor (14) flows through line (15) to the rear of right cylinder head (16).

Coolant from lower outlet of water pump (22) passes through brake oil cooler (23) (located under the front of the engine) and torque converter oil cooler (24) to the left side of cylinder block (17). A small amount of coolant flows from brake oil cooler (23) through line (11) to the coolant discharge side of engine oil cooler. The coolant delivered from the torque converter oil cooler to left side of cylinder block, flows through cylinder block and left cylinder head (18) to coolant return line (6).

If the coolant has not attained operating temperature, water temperature regulators (20) will be closed. The coolant will then flow through top tank (7), bypassing the radiator core (1) and pass through bypass tube (2) to water pump inlet.

When the coolant temperature reaches normal operating level, water temperature regulators (20) will open and allow the coolant to flow through radiator core (1) and out of the bottom tank (19) to water pump inlet.

The fan drive is driven by a set of V-belts from the crankshaft pulley. The fan drive on earlier machines has a fluid coupling. Oil quantity in the coupling is controlled by valve (21) mounted on the side of the water pump inlet housing. Valve (21) senses the temperature of the coolant in the radiator bottom tank. Temperature of coolant controls the opening of fan drive control valve. The hotter the coolant, the more the valve opens, thus the amount of oil to fan drive fluid coupling is increased, increasing the speed of the fan. A drain line at the bottom of the fan drive housing returns the oil to the engine crankcase.

Also included in the cooling system is an air-to-air aftercooler. The aftercooler core is mounted in front of the radiator core. The air discharge from the turbocharger connects to the top of the aftercooler. Air flows downward through the aftercooler core, out the bottom of the aftercooler to the air inlet manifolds of the engine.

Basic Engine Components

Cylinder Block

The cylinder block is a 60° vee. One bank of cylinders is offset from the other bank of cylinders. This offset provides space at each end of the cylinder block for the camshaft drives. The offset also allows two connecting rods to be secured to each connecting rod journal of the crankshaft.

CYLINDER BLOCK
A. Flywheel end. B. Left side. C. Front end. D. Right side.

Crankshaft

The crankshaft transforms the combustion forces in the cylinders into usable rotating torque which powers the machine. There is a timing gear at each end of the crankshaft which drives the respective timing gears.

Interconnecting drilled passages supply pressurized lubricating oil to all bearing surfaces on the crankshaft.

Cylinder Liners

A steel spacer plate is used between the cylinder heads and the cylinder block. The cylinder liners on earlier engine are supported in counterbores in the spacer plate.

On later engines the cylinder liner sits directly on the cylinder block. Engine coolant flows around the liners to cool them. Three O-ring seals at the bottom and a filler band at the top of each cylinder liner form a seal between the cylinder liner and the cylinder block.

Pistons, Rings And Connecting Rods

The piston has three rings; two compression rings and one oil ring. All rings are located above the piston pin bore. The two compression rings seat in an iron band which is cast integrally in the piston. The oil ring is spring loaded. Holes in the oil ring groove provide for the return of oil to the crankcase.

The full-floating piston pin is retained by two snap rings which fit in grooves in the pin bore.

A steel heat plug, in the crater of the piston, protects the top of the piston from erosion and burning at the point of highest heat concentration.

Oil spray jets, located on the cylinder block main bearing webs, direct oil to cool and lubricate the piston components and cylinder walls.

The connecting rods have diagonally cut serrated joints which allow removal of the piston and connecting rod assembly upward through the cylinder liner. Earlier engines use the same part number connecting rod for both odd and even numbered cylinders. This connecting rod uses a locating tab to position the connecting rod bearing.

Connecting rod bearings in later engines do not have locating tabs but are positioned by dowels in the connecting rods. The rods with dowel located bearings are marked "Even Cyl Only ..." or "Odd Cyl Only ...". These rods must be installed in the correct bank. They may be installed in earlier engines if the correct piston cooling jets are installed. Refer to Special Instruction (GEG02495) for complete instructions.

Electrical System

The electrical system is a combination of three separate electric circuits: the charging circuit, the starting circuit and the lighting circuit. Each circuit is dependent on some of the same components. The battery (batteries), disconnect switch, circuit breaker, ammeter, cables and wires from the battery are common in each of the three circuits.

The charging circuit is in operation when the diesel engine is operating. The electricity producing (charging) unit is an alternator. A regulator in the circuit senses the state of charge in the battery and regulates the charging unit output to keep the battery fully charged.

The starting circuit operates only when the disconnect switch is ON and the start switch is actuated.

The direct electric starting circuit includes a glow plug for each diesel engine cylinder. Glow plugs are small heating elements in the precombustion chambers that promote fuel ignition when the engine is started in low temperatures.

The lighting and charging circuits are both connected on the same side of the ammeter while the starting circuit connects to the other side of the ammeter.

System Components

Alternator (5S9088, 5S6698)

5S9088 ALTERNATOR
1. Regulator. 2. Fan. 3. Roller bearing. 4. Rotor. 5. Stator windings. 6. Ball bearing.

This alternator is a belt driven, three phase, self-rectifying, brushless unit with a built-in voltage regulator.

The only moving part in the alternator is the rotor (4) which is mounted on a ball bearing (6) at the drive end, and a roller bearing (3) at the rectifier end.

The regulator is enclosed in a sealed compartment. It senses the charge condition of the battery and the electrical system power demands and controls the alternator output accordingly.

Starting Motor

STARTING MOTOR
1. Field. 2. Solenoid. 3. Clutch. 4. Pinion. 5. Commutator. 6. Brush assembly. 7. Armature.

The starting motor used with direct electric start incorporates a solenoid. The action of the solenoid engages the pinion with the ring gear on the engine flywheel, when the solenoid is energized. The pinion always engages before the electric contacts in the solenoid close the circuit between the battery and the starting motor. An overrunning clutch protects the starting motor from being overspeeded. Releasing the start-switch disengages the pinion from the ring gear on the flywheel.

Solenoid

SCHEMATIC OF A SOLENOID
1. Coil. 2. Switch terminal. 3. Battery terminal. 4. Contacts. 5. Spring. 6. Core. 7. Component terminal.

A solenoid is a magnetic switch that utilizes low current to close a high current circuit. The solenoid has an electromagnet with a movable core (6). There are contacts (4) on the end of the core. The contacts are held open by a spring (5) that pushes the core away from the magnetic center of the coil. Low current will energize the coil and form a magnetic field. The magnetic field draws the core to the center of the coil and the contacts close.

Circuit Breaker

The circuit breaker is a safety switch that opens the battery circuit whenever the current in the electrical system exceeds the rating of the circuit breaker.

A heat sensitive metal disc (4) with a contact point (3) completes the electric circuit through the circuit breaker. Excessive high current in the electric system promotes heat in the metal disc. Heat distorts the disc, causing the contacts to open. An open circuit breaker can be reset after it is allowed to cool. Push the reset button (1) to close the contacts.

SCHEMATIC OF A CIRCUIT BREAKER
1. Reset button. 2. Disc in open position. 3. Contacts. 4. Disc. 5. Battery circuit terminals.

Air Starting System And Controls

AIR STARTING SYSTEM

The optional air starting system and controls consist of:

...a 10 ft.³ air tank (283.2 liter)

...an air starting motor

...a governor override valve

...a pressure protection valve

...a solenoid valve

...a relay valve.

WET TANK
1. Air start pressure protection valve. 2. Wet tank. 3. Supply port. 4. Delivery to air start reservoir.

The air start reservoir is supplied from the standard air system wet tank. When charging the standard brake air system, the pressure protection valve is the supply line to the air starting reservoir. It opens at 80 psi (5.6 kg/cm²) and remains open until system pressure drops to 65 psi (4.6 kg/cm²) when it closes to isolate the starting air system from the brake air system.

AIR STARTING RESERVOIR
5. Air starting reservoir. 6. Relief valve. 7. Line to junction block.

Outlet air from the tank flows through a junction block to the supply ports of the solenoid valve and a relay valve.

The relay valve is mounted on the air starting motor and blocks air flow to the air starting motor until the disconnect switch is turned ON and opens the solenoid for air flow to the relay valve control port. Air then flows from the relay valve delivery port to drive the air starting motor.

AIR STARTING MOTOR
8. Air starting motor.

The compressor governor normally limits air system pressure to 120 psi (8.4 kg/cm²). The governor override valve can be used to build up system pressure at engine shutdown to store additional air in the air starting tank to be used at the next start up.

If the air start tank drains during an extended shutdown period, a quick disconnect coupling is provided so that an external air supply can be used to start the engine.

QUICK DISCONNECT VALVE
9. Junction block. 10. Quick disconnect valve for air starting external air supply.

AIR START SOLENOID VALVE
11. Air start solenoid valve.