1693 DIESEL TRUCK ENGINE Caterpillar


Systems Operation

Usage:



Engine Design

Bore ... 5.40 in.(137.2 mm)

Stroke ... 6.5 in.(165.1 mm)

Number and Arrangement of Cylinders ... In line 6

Firing Order (Injection Sequence) ... 1,5,3,6,2,4

Rotation of Crankshaft (when seen from flywheel end) ... counterclockwise

Rotation of Fuel Pump Camshaft (when seen from pump drive end) ... counterclockwise

NOTE: Front end of engine is opposite to flywheel end. Left side and right side of engine are as seen from flywheel end. No. 1 cylinder is the front cylinder.

Fuel System


FUEL SYSTEM
1. Damper. 2. Injection pump housing. 3. Fuel supply line. 4. Fuel return line. 5. Air vent valve. 6. Fuel tank. 7. Priming pump. 8. Transfer pump. 9. Bypass valve. 10. Main fuel filter.

This engine has a pressure type fuel system. There is one injection pump and injection valve for each cylinder. The injection pumps are in pump housing (2) on the right side of the engine. The injection valves are in the precombustion chambers in the cylinder head under the valve cover.

The transfer pump (8) pulls fuel from fuel tank (6) through the primary filter and main filter (10). It sends the fuel through fuel supply line (3) to the manifold of the injection pump housing. The fuel in the manifold goes to the injection pumps. The injection pumps are in time with the engine and send fuel to the injection valves under high pressure.

Bypass valve (9) gives control to the fuel pressure. The extra fuel from the valve goes back to the tank through return line (4).

Open air vent valve (5) and use priming pump (7) to remove air from the fuel filter, fuel lines, and components.

Damper (1) prevents sharp pressure increases in the system.

Fuel Injection Pump Operation

Injection pump plungers (5) and lifters (8) are lifted by cams on camshaft (9) and always make a full stroke. The force of springs (6) hold the lifters (8) against the cams of the camshaft.

Fuel from fuel manifold (1) goes through inlet port (2) in the barrel and then into the chamber above plunger (5). During injection, the camshaft cam moves plunger (5) up in the barrel. This movement will close inlet port (2) and push the fuel out through the fuel lines to the injection valves.

The amount of fuel sent to the injection valves is controlled by turning plunger (5) in the barrel. When the governor moves fuel rack (7), the fuel rack moves gear (4) that is fastened to the bottom of plunger (5).


FUEL INJECTION PUMP HOUSING
1. Fuel manifold. 2. Inlet port. 3. Check valve. 4. Gear segment. 5. Pump plunger. 6. Spring. 7. Fuel rack. 8. Lifter. 9. Camshaft.

Hydra-Mechanical Governor

The accelerator pedal, or governor control, is connected to the control lever on the engine governor. The governor controls the amount of fuel needed to keep the desired engine rpm.

The governor has governor weights (15), driven by the engine, governor spring (5), valve (14) and piston (13). The valve and piston are connected to fuel rack (10). The pressure oil for the governor comes from the engine oil pump. Pressure oil goes through passage (11) and around sleeve (12). The accelerator pedal, or governor control, controls only the compression of governor spring (5). Compression of the spring always pushes to give more fuel to the engine. The centrifugal force (rotation) of governor weights (15) is always pulling to get a reduction of fuel to the engine. When these two forces are in balance, the engine runs at the desired rpm (governed rpm).

The governor valve is shown in the position when the force of the governor weights and the force of the governor spring are in balance.

When there is an increase in engine load, there will be a decrease in engine rpm and the rotation of governor weights (15) will get slower. (The governor weights will move toward each other). Governor spring (5) moves valve (14) forward. When valve (14) moves forward, an oil passage around valve (14) opens to pressure oil. Oil now flows through passage (3) and fills the chamber behind piston (13). This pressure oil pushes the piston and rack forward to give more fuel to the engine. Engine rpm goes up until the rotation of the governor weights is fast enough to be in balance with the force of the governor spring.


HYDRA-MECHANICAL GOVERNOR
1. Cylinder. 2. Drive gear. 3. Oil passage. 4. Thrust bearing. 5. Governor spring. 6. Seat. 7. Lever assembly. 8. Bolt. 9. Collar. 10. Fuel rack. 11. Oil passage. 12. Sleeve. 13. Piston. 14. Valve. 15. Weights. 16. Spring seat. 17. Speed limiter plunger.

When there is a reduction in engine load, there will be an increase in engine rpm and the rotation of governor weights (15) will get faster. This will move valve (14) backwards. This movement lets the oil behind piston (13) go through an open passage at the rear of the piston. Now, the pressure oil between sleeve (12) and piston (13) pushes the piston and fuel rack backwards. There is now a reduction in the amount of fuel to the engine. Engine rpm goes down until the centrifugal force (rotation) of the governor weights is in balance with the force of the governor spring. When these two forces are in balance, the engine will run at the desired rpm (governed rpm).

To stop the engine, turn the switch to the "OFF" position. This will cause the shutoff solenoid to move a lever that moves the fuel rack to the fuel closed position. With no fuel going to the engine cylinders, the engine will stop.

After the engine has stopped, the small spring moves valve (14) and piston (13) to the full load position. This moves the rack to full travel position and gives full fuel flow through the fuel injection pump when starting the engine.

When the governor control is moved to fuel-on position to start the engine, plunger (17) of the speed limiter puts a restriction on the movement of lever assembly (7). After oil pressure of the engine gets to a safe level, plunger (17) of the speed limiter moves back (out of the way) and the governor control can be moved to increase engine rpm.

Oil from the engine gives lubrication to the governor weight bearing. The other parts of the governor get lubrication from "splash-lubrication" (oil thrown by other parts). Oil from the governor runs back into the housing for the fuel injection pumps.

Hydraulic Air-Fuel Ratio Control

The hydraulic air-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 air-fuel ratio control keeps engine performance high so that black exhaust gases are not seen.

The hydraulic air-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 and 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).


HYDRAULIC AIR-FUEL RATIO CONTROL
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.

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 Injection Valve

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.


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

Variable Timing Drive For Fuel Injection Pump Camshaft

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

On engines with Serial Numbers 65B782 thru 65B7058 the timing advances from 11° BTC at low idle to 19° BTC at high idle. On engines with Serial Numbers 65B7059-Up the timing advances from 8° BTC at low idle to 19° BTC at high idle.

During engine low rpm operation, the flyweight (7) force is not sufficient to overcome the force of control valve spring (2) and move control valve (3) to the closed position. Oil merely flows through the power piston cavity (8).


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

As the engine rpm increases, flyweights (7) overcome the force of control valve spring (2) and move control valve (3) to the closed position, blocking the oil drain port (4). Pressurized oil, trapped in power piston cavity (8), overcomes the force of spring (6) and moves power piston (9) outward. This causes the fuel injection pump camshaft to index slightly ahead of the shaft portion (1) of the variable timing drive. 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 (6) 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 (3) 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 (1) drive the governor drive pinion.

Air Inlet And Exhaust System


AIR INLET AND EXHAUST SYSTEM
1. Exhaust outlet. 2. Air inlet pipe. 3. Aftercooler. 4. Turbocharger. 5. Piston and cylinder. 6. Exhaust manifold. 7. Air inlet.

The air inlet and exhaust system components are: air cleaner, inlet manifold, cylinder head, valves and valve system components, exhaust manifold, and turbocharger.

Clean inlet air from the air cleaner is pulled through the air inlet (7) of the turbocharger by the turning compressor wheel. The compressor wheel causes a compression of the air. The air then goes to the inlet pipe (2) of the engine. When the intake valves open, the air goes into the engine cylinder (5) and is mixed with the fuel for combustion. When the exhaust valves open, the exhaust gases go out of the engine cylinder and into the exhaust manifold (6). From the exhaust manifold, the exhaust gases go through the blades of the turbine wheel. This causes the turbine wheel and compressor wheel to turn. The exhaust gases then go out the exhaust outlet (1) of the turbocharger.

Aftercooler

Some engines have an aftercooler (1) installed in place of the inlet manifold.


AIR INLET SYSTEM
1. Aftercooler.

The aftercooler lowers the temperature of the inlet air coming from the compressor outlet of the turbocharger to approximately 200° F (93° C). This cooler air then goes into the engine cylinders.

Coolant for the aftercooler comes from the front bonnet on the oil cooler.

Turbocharger

The turbocharger is installed on the center section of the exhaust manifold. All the exhaust gases from the engine go through the turbocharger.


TURBOCHARGER
1. Turbocharger. 2. Inlet pipe. 3. Exhaust manifold.

The exhaust gases go through the blades of the turbine wheel. This causes the turbine wheel and compressor wheel to turn which causes a compression of the inlet air.

When the load on the engine goes up more fuel is put into the engine. This makes more exhaust gases and will cause the turbine and compressor wheels of the turbocharger to turn faster. As the turbocharger turns faster, it gives more inlet air and makes it possible for the engine to burn more fuel and will give the engine more power.

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.

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

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.

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


TURBOCHARGER (Typical Example)
4. Air inlet. 5. Compressor wheel. 6. Turbine wheel. 7. Exhaust outlet. 8. Compressor housing. 9. Thrust bearing. 10. Sleeve. 11. Lubrication inlet port. 12. Turbine housing. 13. Sleeve. 14. Sleeve. 15. Oil deflector. 16. Bearing. 17. Oil outlet port. 18. Bearing. 19. Exhaust inlet. 20. Air outlet.

The bearings for the turbocharger use engine oil under pressure for lubrication. The oil comes in through the oil inlet port and goes through passages in the center section for lubrication of the bearings. Oil from the turbocharger goes out through the oil outlet port 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.

Valves And Valve System Components


VALVE AND VALVE MECHANISM
1. Rotocoil. 2. Valve retainer and lock. 3. Spring. 4. Washer. 5. Guide. 6. Valve. 7. Valve seat insert.

The valves and valve system components control the flow of inlet air and exhaust gases into and out of the cylinder during engine operation.

The intake and exhaust valves are opened and closed by movement of these components: crankshaft, camshaft, follower and valve springs. Rotation of the crankshaft causes rotation of the camshaft. The camshaft gear is timed to, and driven by, a gear on the rear of the crankshaft. As the camshaft turns, the lobes of the camshaft also turn and cause the valve lifters (cam followers) to go up and down. There is a camshaft lobe for each valve in the cylinder head. There are two intake and two exhaust valves for each cylinder.

Movement of the followers will make the intake and exhaust valves in the cylinder head open and close by the firing order (injection sequence) of the engine. One valve spring for each valve helps to hold the valves in the closed position.

Valve rotators cause the valves to have rotation while the engine is in operation. This rotation of the valves keeps the deposit of carbon on the valves to a minimum and gives the valves longer service life.

Timing Gears

The timing gears are at the rear of the cylinder block. Their cover is the housing for the timing gears. The timing gears keep the rotation of the crankshaft, camshaft, and fuel injection pump in the correct relation to each other. The timing gears are driven by the crankshaft gear.


TIMING GEARS
1. Camshaft drive gear. 2. Camshaft idler gear. 3. Accessory drive idler gear. 4. Air compressor drive gear. 5. Accessory drive gear. 6. Cluster gear. 7. Crankshaft gear. 8. Oil pump drive gear.

Lubrication System


LUBRICATION SYSTEM COMPONENTS
1. Turbocharger inlet. 2. Turbocharger drain. 3. Oil filter outlet. 4. Oil manifold (in block). 5. Oil cooler outlet. 6. Oil pump (in oil pan). 7. Oil pan. 8. Lubrication valve. 9. Oil cooler inlet. 10. Oil cooler.

The lubrication system has the following components: oil pan, oil pump, oil cooler, oil filter, oil lines to and from the turbocharger and oil passages in the cylinder block.

Oil Flow Through The Oil Filter And Oil Cooler

With the engine warm (normal operation), oil comes from oil pan (13) through a suction bell to oil pump (19). The oil pump sends warm oil to oil cooler (18) and then to oil filters (16).

From the oil filters, oil is sent to bypass valve (14) of the lubrication valve. This oil then goes to oil manifold (12) in the cylinder block and oil supply line (10) for the turbocharger. Oil from the turbocharger goes through an oil return line to oil pan (13).

When cold oil with high viscosity causes a restriction to the oil flow through oil cooler (18) and oil filters (16), (starting conditions), plunger (15) of the lubrication valve gives immediate lubrication to all components. Bypass valve (14) prevents reverse flow of cold oil through the oil filter. The oil pump then sends the cold oil to oil manifold (12) in the cylinder block and to supply line (10) for the turbocharger. Oil from the turbocharger goes back through the oil return line to the oil pan.


FLOW OF OIL (ENGINE WARM)
1. To camshaft and bearings. 2. Air compressor idler gear bearing. 3. Bore for camshaft. 4. From rear housing. 5. Variable timing gear idler bearing. 6. To rear housing. 7. To fuel injection pump housing. 8. Piston cooling tubes. 9. Filter bypass. 10. To turbocharger. 11. Main bearings. 12. Oil manifold. 13. Oil pan. 14. Bypass valve. 15. Plunger. 16. Oil filter. 17. Bypass line. 18. Oil cooler. 19. Oil pump.

When the pressure difference in the plunger decreases, the plunger closes. Now there is a normal oil flow through the oil cooler and oil filter. The oil now goes through bypass valve (14). Plunger (15) prevents reverse oil flow through bypass line (17). Filter bypass valve (9) is open only a few seconds and closes before the oil gets warm.

Bypass valve (9) will also open when there is a restriction in the oil filter. This action does not let an oil cooler or oil filter with a restriction prevent the lubrication of the engine.

Oil Flow In The Engine

Oil from oil manifold (12) in the cylinder block goes through drilled passages in the block to main bearings (11). Oil goes through drilled holes in the crankshaft to give lubrication to the connecting rod bearings. A small amount of oil goes through tubes (8) to make the pistons cooler.

Oil from the oil manifold also goes into the flywheel housing for timing gear lubrication. The oil comes back into the cylinder block through return passage (4).

This oil goes to variable timing gear idler bearing (5), air compressor idler gear bearing (2), and camshaft bearings (3).

From the oil manifold at passage (7) oil goes to the fuel injection pump housing. This oil is for injection pump, governor and the variable timing drive.

There is a bypass valve in the oil pump. This bypass valve controls the maximum pressure of the oil from the oil pump. The oil pump can put more oil into the system than is needed. When there is more oil than needed, the oil pressure will increase and the bypass valve will open. This allows the oil that is not needed to go back to the inlet passage of the oil pump.

After the oil has done its work, it goes back to the engine oil pan.


FLOW OF OIL (ENGINE COLD)
9. Filter bypass. 10. To turbocharger. 13. Oil pan. 14. Bypass valve. 15. Plunger. 16. Oil filter. 17. Bypass line. 18. Oil cooler. 19. Oil pump.

Lubrication System (Engine With BrakeSaver)

Component Location


BRAKESAVER COMPONENTS (65B728-65B10328)
1. Turbocharger inlet oil line. 2. Turbocharger outlet oil line. 3. BrakeSaver (located in flywheel housing). 4. BrakeSaver control valve. 5. Oil inlet from BrakeSaver oil cooler. 6. Coolant inlet to engine (from oil cooler). 7. Lubrication valve. 8. Oil bypass line (from engine to priority valve). 9. Oil inlet (from oil filter to lubrication valve). 10. Oil outlet (from priority valve to oil filter). 11. Poppet valve. 12. Differential pressure valve. 13. Oil outlet (from control valve to oil cooler). 14. Oil line (from priority valve to control valve). 15. Oil outlet to oil filter. 16. Drain line from priority valve. 17. Priority valve. 18. Coolant outlet (from water pump to oil cooler).

Both the turbocharged and the turbocharged-aftercooled engines have a hydraulically-operated BrakeSaver. The BrakeSaver helps control deceleration of a vehicle on grades, curves and at other times when speed reduction is necessary but long applications of the service brakes are not desirable. The BrakeSaver adds to service brake life; there is no noise and no muffler is needed; it does not put an extra load on the valve mechanism to cause wear; and it can hold up to 100% of the rated engine horsepower at the flywheel.


BRAKESAVER COMPONENTS (65B10329-UP)
1. BrakeSaver (located in flywheel housing). 2. BrakeSaver control valve. 3. Oil inlet from BrakeSaver oil cooler. 4. Turbocharger inlet oil line. 5. Turbocharger outlet oil line. 6. Oil inlet (from oil filter to manifold). 7. Oil line (from priority valve to oil filter). 8. BrakeSaver oil cooler. 9. Poppet valve. 10. Differential pressure valve. 11. Oil outlet (from control valve to oil cooler). 12. Oil line (from priority valve to control valve). 13. Oil outlet to oil filter. 14. Priority valve. 15. Oil inlet (from control valve to oil cooler).

The BrakeSaver is inside flywheel housing. Fastened to the right side of the engine are control valve body, oil lines, oil cooler, and priority valve. The oil cooler for engines 65B782-65B10328 is remote mounted. The oil cooler for engines 65B10329-UP is mounted on the side of the engine. Passages in the flywheel housing let oil go from the control valve body to the BrakeSaver. Other passages let oil flow from the BrakeSaver back to the control valve body. The oil that fills the BrakeSaver comes from the engine lubrication circuit. With the BrakeSaver installed, oil capacity of the engine crankcase is approximately 3 U.S. gallons (11 litres) more than the crankcase capacity of the standard 1693 Engine.

Oil Flow Through Oil Filter


OIL FLOW ENGINE COLD
1. Oil pump. 2. Oil manifold. 3. Oil filters. 4. Priority valve. 5. Control valve body. 6. Oil cooler.

When the engine is started, oil pressure is low. Oil from the engine oil pump (1) moves through priority valve (4) and engine oil filters (3) to engine oil manifold (2) in the cylinder block. Because oil pressure is low, the check valve in the priority valve keeps engine oil from going to control valve body (5) for the BrakeSaver. Oil goes through the priority valve to the engine oil manifold and the engine components get the full pump flow.

Oil Flow Through Oil Cooler


OIL FLOW ENGINE WARM BRAKESAVER "OFF"
1. Oil pump. 2. Oil manifold. 3. Oil filters. 4. Priority valve. 5. Control valve body. 6. Oil cooler.

As the engine runs, oil pressure goes up. When oil pressure is 35 psi (240 kPa) at the engine oil manifold, priority valve (4) moves to send all oil flow to control valve body (5), oil cooler (6), back to the control valve and the priority valve and through the engine oil filters (3) to the engine oil manifold.

Oil Flow Through BrakeSaver


SCHEMATIC OF BRAKESAVER IN "ON" POSITION
1. Oil pump. 2. Oil manifold. 3. Oil filters. 4. Priority valve. 5. Control valve body. 6. Oil cooler. 7. BrakeSaver manual control lever. 8. BrakeSaver. 9. Air line.

When the BrakeSaver manual control lever (7) is moved to let air pressure come into air line (9), the BrakeSaver is activated. Air pressure moves the valve spool in control valve body (5) and the flow of oil changes. Oil from priority valve (4) goes through control valve body (5) to BrakeSaver (8) and then back to control valve body (5). From control valve body (5), oil goes to oil cooler (6) and then back to control valve body (5). The oil can now be sent to BrakeSaver (8) or the engine oil manifold.

Cooling System


COOLING SYSTEM COMPONENTS
1. Aftercooler outlet elbow. 2. Aftercooler. 3. Outlet hose. 4. Vent line aftercooler to regulator. 5. Aftercooler inlet. 6. Radiator. 7. Shunt line. 8. Temperature regulator. 9. Oil cooler. 10. Bypass line. 11. Water pump. 12. Inlet hose.

This engine has a pressure type cooling system equipped with a shunt line (7).

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

A shunt line (7) gives several advantages. The shunt line gives a positive pressure of coolant at the water pump inlet to prevent cavitation. The shunt line let air in the cooling system go out of the coolant through the vent tube in the radiator. When the cooling system is first filled, the shunt line lets the cooling system fill from the bottom to push any air in the system out the top.

In normal operation (engine warm) the water pump (11) sends coolant through the oil cooler (9) and into the cylinder block. Coolant moves through the cylinder block into the cylinder head and then goes to the housing for the temperature regulator (8). The temperature regulator is open and the coolant goes through the outlet hose (3) to the radiator (6). The coolant is made cooler as it moves through the radiator. When the coolant gets to the bottom of the radiator, it goes through the inlet hose (12) and into the water pump.

NOTE: The water temperature regulator (8) is an important part of the cooling system. If the water temperature regulator is not installed in the system, the coolant will not go through the radiator and overheating (engine runs too hot) will be the result.

A small amount of coolant is moving constantly up through the vent tube between the lower and upper compartment in the top tank of the radiator. Since the flow through the vent tube is small and the volume of the upper compartment is large, air in the coolant comes out of the coolant as the coolant goes into the upper compartment. A small flow of coolant constantly goes through the shunt line (7) to the inlet of the water pump.

When the engine is cold, the water temperature regulator (8) is closed, and the coolant is stopped from going to the radiator. The coolant goes from the housing for the temperature regulator back to the water pump (11) through bypass line (10).

Engines Equipped With Aftercooler

The flow of coolant through these engines is the same as the flow through engines that do not have an aftercooler with one addition. A small amount of coolant goes through tube (5) to the aftercooler (2). This coolant goes through the aftercooler and out elbow (1) and back into the cylinder block.

Engines Equipped With A BrakeSaver

The cooling system for an engine with a BrakeSaver is the same as the cooling system for an engine with no BrakeSaver. The oil cooler on an engine with a BrakeSaver is larger but it is still found in the same location on the engine. It has the same water flow through it as the oil cooler on an engine with no BrakeSaver.

Basic Block


CROSS SECTION OF A VIBRATION DAMPER
1. Flywheel ring. 2. Rubber ring. 3. Inner hub.

The twisting of the crankshaft, due to the regular power impacts along its length, is called twisting (torsional) vibration. The vibration damper is installed on the front end of the crankshaft. It is used for reduction of torsional vibrations and stops the vibration from building up to amounts that cause damage.

The damper is made of a flywheel ring (1) connected to an inner hub (3) by a rubber ring (2). The rubber makes a flexible coupling between the flywheel ring and the inner hub.

Electrical System

The electrical system has two separate circuits: the charging circuit and the starting circuit. Some of the electrical system components are in more than one circuit. The battery (batteries), disconnect switch, circuit breaker, ammeter, cables and wires from the battery are all common in each of the circuits.


NOTICE

The disconnect switch must be in the ON position to let the electrical system operate. There will be damage to some of the charging circuit components if the engine is running with the disconnect switch in the OFF position.


The charging circuit is in operation when the engine is running. An alternator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output to keep the battery at full charge.

The starting circuit is in operation only when the disconnect switch is put in the ON position and the start switch is activated.

When so equipped, the starting circuit has a glow plug for each cylinder of the diesel engine. Glow plugs are small heating units in the precombustion chambers. Glow plugs give aid for ignition of the fuel when the engine is started in temperatures that are low.

The low amperage load circuit and the charging circuit are both connected to the same side of the ammeter. The starting circuit connects to the opposite side of the ammeter.

System Components


NOTICE

Never operate the alternator without the battery in the circuit. Making or breaking an alternator connection with heavy load on the circuit can cause damage to the regulator.


Alternator

The alternator is a three phase self-rectifying charging unit. The alternator is driven from the crankshaft pulley by V type belts.

The only part in the alternator that has movement is the rotor.

The alternator has four main components: end frame assembly (brush end), rotor assembly, stator and shell assembly, and end frame assembly (drive end).


ALTERNATOR

Alternator Regulator

The alternator regulator is a part of the alternator and it is a solid state (no moving parts) type regulator.

The alternator regulator controls the alternator output according to what the battery and the other components in the electrical system need.


ALTERNATOR REGULATOR
1. Plug. 2. Connector.

Starting Motor

The starting motor is a device used to rotate the flywheel of an engine fast enough to start the engine.


CROSS SECTION OF A 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

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. There are contacts on the end of the core. The contacts are held open by a spring 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.


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

Shutoff Solenoid

The rack shutoff solenoid, when energized, moves the shutoff lever in the governor housing which in turn moves the fuel rack to the shutoff position. The solenoid is energized by a manual control switch located in the cab of the truck.


SHUTOFF SOLENOID

BrakeSaver

BrakeSaver Components

All of the BrakeSaver components are inside engine flywheel housing (10). They are between crankshaft (5) and engine flywheel (2). The BrakeSaver front seal adapter (3) is fitted on the rear drive gear of the crankshaft. This adapter has one of the bronze seals (6) that runs against wear sleeve (1). Bolts hold the wear sleeve to the flywheel housing. Rotor (8) and the flywheel are fastened to the crankshaft. (Both components use the same bolts.) When the flywheel bolts are tight, the rotor is held between the flywheel and the crankshaft. These components turn when the engine is operating.

Another bronze seal (6) is in the hub of rotor (8), and runs against the inside diameter of stator (9). The stator is fastened to the flywheel housing. When the BrakeSaver is full of pressure oil, the two bronze seals (6) prevent oil leakage from the fluid compartment of the BrakeSaver. If oil leakage gets through the bronze seal in the rotor hub, it is stopped by lip-type seal (7). This oil can go back to the engine crankcase through two of the three drilled passages (4) in stator (9).


BRAKESAVER COMPONENTS
1. Wear sleeve. 2. Engine flywheel. 3. BrakeSaver seal adapter. 4. Drilled passages. 5. Crankshaft. 6. Bronze seals (two). 7. Lip-type seal. 8. Rotor. 9. Stator. 10. Flywheel housing.

BrakeSaver Operation

In downhill operation, the crankshaft is turned by the rear wheels (through the differential, driveshaft, transmission, and clutch). To reduce the speed of the vehicle, an application of a braking force can be made to the crankshaft. The BrakeSaver does this through the conversion of the energy of rotation into heat which is removed by the engine cooling system.

The rotor (3) is fastened to and turns with the engine crankshaft. The rotor has pockets (5) on the outer circumference of both sides and four holes to permit equal oil flow to both sides of the rotor.

Stator (2) is fastened to flywheel housing (1) and can not turn. Both the flywheel housing and the stator have pockets (4) on their inside surfaces in alignment with pockets (5) in the rotor.

Rotor (3) turns in the compartment made by stator (2) and flywheel housing (1). When the BrakeSaver is in operation, engine oil comes into this compartment near the center through a passage from the top of the BrakeSaver housing. The rotor, turning with the crankshaft, throws this oil outward. As the oil flows outward, the shape of the rotor pockets send it into the pockets of the stator and flywheel housing. As the rotor turns and the oil flows around the BrakeSaver compartment, it takes the shape of a spiral.


BRAKESAVER OPERATION
1. Flywheel housing. 2. Stator. 3. Rotor. 4. Stator pockets. 5. Rotor pockets.


OIL FLOW THROUGH BRAKESAVER (TYPICAL EXAMPLE)
1. Flywheel housing. 2. Stator. 3. Rotor. 4. Pocket. 5. Pocket.

As the oil flows around the BrakeSaver compartment, it is constantly cut by the vanes (the material between the pockets) of the rotor. This cutting action gives resistance to the rotor and changes the energy of the rotor into heat in the oil. The heat is removed by the oil cooler and goes into the engine cooling system.

The control of the BrakeSaver has as its basis the principle that the braking force available has a direct relation to the amount of oil being cut by the rotor vanes. When the BrakeSaver is not in operation, the inlet passage to the rotor compartment is closed by the control valve and there is no oil in the BrakeSaver compartment.

As the BrakeSaver inlet passage is opened, the oil starts to flow in a spiral shape between the rotor and the stator. Inside this spiral flow (6) of oil is an air pocket (7). As the pressure in the rotor compartment increases, the amount of oil in the spiral flow increases in thickness and the air pocket has compression. As this air pocket has compression, the amount of oil being cut by the rotor vanes has an increase. The inlet oil pressure is used to control the level of braking in the BrakeSaver.


OIL FLOW IN BRAKESAVER (TYPICAL EXAMPLE)
1. Flywheel housing. 2. Stator. 3. Rotor. 6. Spiral flow. 7. Air pocket.

BrakeSaver Control Valve Operation

This is a schematic of control valve body (6) and control valve spool (5). BrakeSaver (9) is not activated and engine oil pressure is more than 35 psi (240 kPa). Flow from the engine oil pump goes through the priority valve and comes into control valve body (6) through a passage (4) near the middle of the valve spool bore. Oil goes around valve spool (5), through oil cooler (2), and back to valve spool (5). Oil goes around the valve spool and through a passage (1) to the engine oil filter. BrakeSaver (9) has no oil at this time.

NOTE: A small poppet valve (8) lets approximately 1 U.S. gpm (3.8 litre/min) go to the BrakeSaver when the valve spool is in this position. This small flow of oil becomes the lubricant for the bronze seals in the BrakeSaver when the BrakeSaver is not filled with oil.


BRAKESAVER CONTROL VALVE IN BRAKESAVER "OFF" POSITION
1. Passage to oil filter. 2. Oil cooler. 3. Air line. 4. Oil inlet passage. 5. Valve spool. 6. Control valve body. 7. Differential pressure valve. 8. Poppet valve. 9. BrakeSaver.

In this schematic, we see the first motion of valve spool (5) when pressure air gets into air line (3). Pressure air moves valve spool (5) to the right. Oil comes into control valve body (6) through passage (4) in the center of the valve spool bore. Oil goes around valve spool (5) to BrakeSaver (9). The BrakeSaver rotor pushes oil around valve spool (5) to oil cooler (2). Oil from the oil cooler goes back to valve spool (5). When the valve spool moves to the right, it closes passage (1). This would let oil go to the engine oil manifold but a passage opens to let oil go back to BrakeSaver (9). This is now a "closed" circuit. With the closed circuit, it takes approximately two seconds to fill the BrakeSaver and get the pressure to operating level.


BRAKESAVER CONTROL VALVE IN BRAKESAVER "ON" POSITION
1. Passage to oil filter. 2. Oil cooler. 3. Air line. 4. Oil inlet passage. 5. Valve spool. 6. Control valve body. 7. Differential pressure valve. 8. Poppet valve. 9. BrakeSaver.

NOTE: When the BrakeSaver has oil, the BrakeSaver rotor becomes a pump. The oil flow in the circuit is approximately 120 U.S. gpm (454.0 litre/min) for engines 65B782-65B10328 and 90 U.S. gpm (340.7 litre/min) for engines 65B10329-UP. This is the flow rate when the engine is running at 2100 rpm until the air in air line (3) is released. During the two seconds necessary for the BrakeSaver pressure to get to operating level, there will be a pressure decrease in the engine oil manifold. The priority valve will move to let some oil go to the engine oil manifold and some to the BrakeSaver.

A (differential) pressure ratio valve assembly (7) is fastened to the bottom of control valve body (6). Passages in control valve body (6) let BrakeSaver inlet pressure oil (10) go to the top of differential pressure valve (7). Pressure oil from BrakeSaver outlet (exhaust) (11) goes to the lower passage in (differential) pressure valve (7). Engine oil pressure is approximately 70 psi (480 kPa). When control valve spool (5) moves to send the oil flow to the empty BrakeSaver, there is a decrease in inlet pressure. BrakeSaver inlet and outlet pressure will go up from the same pressure level but outlet pressure will have a faster increase. When the BrakeSaver is completely filled and under pressure, outlet oil pressure will be 42 to 62 psi (290 to 430 kPa) higher than inlet oil pressure. This difference in pressure is called the "pressure head."

As the pressures go up, outlet pressure moves (differential) pressure valve (7), and some oil goes into the spring bore of valve spool (5). Differential pressure plus spring force moves valve spool (5) against air pressure in air line (3). The valve spool is now a flow control valve. There is no closed circuit. If the pressure head is high, the valve spool moves to the left and lowers BrakeSaver inlet pressure. The braking effect is also lowered. When the pressure head is low, air pressure moves the valve spool to the right. This causes an increase in BrakeSaver inlet pressure and an increase in braking effect.


BRAKESAVER CONTROL VALVE IN FLOW CONTROL POSITION
1. Passage to oil filter. 2. Oil cooler. 3. Air line. 4. Oil inlet passage. 5. Valve spool. 6. Control valve body. 7. Differential pressure valve. 8. Poppet valve. 9. BrakeSaver. 10. BrakeSaver inlet pressure. 11. BrakeSaver outlet pressure.

BrakeSaver Operator Controls

Two types of controls are available for the BrakeSaver: a manual control and an automatic control. Supply air goes into the circuit through pressure reducing valve (17). The pressure reducing valve keeps a maximum pressure in the control circuit of 40 psi (280 kPa).

This pressure air is available at manual control lever (2) in the operator's compartment and at the solenoid valve (8). When ignition switch (5) is turned ON, the electrical circuit to manual-automatic switch (3) has current available. [Switch (3) is shown in the MANUAL position.] In the MANUAL position, switch (3) opens the circuit. The automatic section of switch (3) is in the OFF position and the BrakeSaver can only be operated manually.

NOTE: Maximum supply air pressure from the air compressor (not shown) is 125 psi (860 kPa).


BRAKESAVER CONTROL CIRCUIT SCHEMATIC
1. Pressure reducing valve. 2. Manual control lever. 3. Manual-automatic selector switch. 4. Control valve. 5. Ignition switch. 6. Double check valve. 7. Accelerator switch. 8. Solenoid valve. 9. Clutch switch.

Manual Control

When the BrakeSaver manual-automatic selector switch (3) is in the MANUAL position, the BrakeSaver can only be turned on by the operator by moving manual control lever (2). With control lever (2) in the BrakeSaver ON position, air goes through manual control lever (2) and double check valve (6) to control valve (4). A valve spool moves and the BrakeSaver gets oil. It holds this oil until manual control lever (2) is moved to the BrakeSaver OFF position. Air can go from control valve (4) to the atmosphere through manual control lever (2).

The farther control lever (2) is moved toward the ON position, the higher the pressure of the air sent to the control valve. An increase in air pressure in the control valve causes an increase in the oil pressure in the BrakeSaver. An increase in the oil pressure in the BrakeSaver causes an increase in the braking force in the BrakeSaver. The operator can give modulation to the braking force in the BrakeSaver through the movement of control lever (2).

An air pressure gauge gives the operator a relative indication of the air pressure being sent to the control valve. Through the use of the indication on the air pressure gauge in relation to engine rpm, the operator can get approximately the same braking effect from the BrakeSaver time after time. This lets the operator more easily control the desired wheel speed of the vehicle.

An oil temperature gauge gives the operator an indication of the ability of the engine cooling system to control the heat in the BrakeSaver during its operation. If the gauge reads too HOT, move control lever (2) to the OFF position and use the service brakes to control the wheel speed of the vehicle. With the BrakeSaver off, the oil temperature will rapidly become normal again and the BrakeSaver can be used.


NOTICE

Do not manually engage the BrakeSaver and control the wheel speed with the accelerator. The design of the cooling system is for the control of the temperature of the oil at full engine power or full BrakeSaver capacity, but not both at the same time.



BRAKESAVER CONTROL CIRCUIT SCHEMATIC (MANUAL-AUTOMATIC Selector Switch in MANUAL Position)
1. Pressure reducing valve. 2. Manual control lever. 3. Manual-automatic selector switch. 4. Control valve. 5. Ignition switch. 6. Double check valve. 7. Accelerator switch. 8. Solenoid valve. 9. Clutch switch.

Automatic Control

All the components of the manual control are in the automatic control and their functions are the same. In the automatic control, there is also a solenoid valve (8) and three switches (3), (7), and (9). The solenoid valve (8) (when activated) sends pressure air from the pressure reducing valve (1) to control valve (4). The solenoid valve is connected to three switches: manual-automatic selector switch (3), accelerator switch (7), and clutch switch (9). The switches are connected to each other in series (all switches must be closed to activate the solenoid). The source of electric current is from ignition switch (5) which prevents the solenoid valve from being activated when the ignition switch is OFF.

The selector switch has two positions: MANUAL and AUTOMATIC-MANUAL. For automatic operation of the BrakeSaver, the selector switch must be in the AUTOMATIC-MANUAL position.

The clutch switch (9) is connected to the clutch linkage. When the clutch is engaged (clutch pedal up), the switch is closed. For automatic operation of the BrakeSaver, the clutch switch must be CLOSED (pedal up).

NOTE: In vehicles with no clutch pedal, the clutch switch is removed from the circuit.

The accelerator switch (7) is installed in the governor. When the accelerator is released (accelerator pedal up), the switch is closed. For automatic operation of the BrakeSaver, the accelerator switch must be closed (accelerator pedal up).

When the switches are closed, the electric current from the ignition switch (5) opens the solenoid valve (8). When the solenoid valve is open, full air pressure [50 psi (345 kPa)] is sent through double check valve (6) to control valve (4). The double check valve keeps the pressure air from going out of the system through the manual control valve when control lever (2) is not in use. It also keeps the pressure air from going out of the system through the solenoid valve (8) when the manual control is in use.

Because the solenoid valve sends full air pressure to the BrakeSaver control valve, there is no modulation in the AUTOMATIC-MANUAL position.

When the selector switch (3) is in the AUTOMATIC-MANUAL position and the accelerator pedal is released (pedal up), the BrakeSaver is operating at its maximum capacity. When the clutch is released (pedal down) the BrakeSaver goes off. When the clutch is engaged again (pedal up), the BrakeSaver comes back on. A light pressure on the accelerator pedal turns the BrakeSaver off and lets the vehicle run freely. More pressure on the accelerator pedal sends fuel to the engine.

When the BrakeSaver is turned off, the pressure air goes out of the system through a passage in the manual control valve or in the solenoid valve (8). This lets the pressure air out of control valve (4) and removes the braking force from the BrakeSaver.

The manual control lever (2) can be operated with the selector switch in the AUTOMATIC-MANUAL position. During normal operation, the solenoid valve will send full air pressure to the BrakeSaver control valve and remove the effect of the manual control valve. If there is a failure in the electrical system when the selector switch is in the AUTOMATIC-MANUAL position, the manual control valve will have an effect.


BRAKESAVER CONTROL CIRCUIT SCHEMATIC (Manual-Automatic Switch in AUTOMATIC Position)
1. Pressure reducing valve. 2. Manual control lever. 3. Manual-automatic selector switch. 4. Control valve. 5. Ignition switch. 6. Double check valve. 7. Accelerator switch. 8. Solenoid switch. 9. Clutch switch.

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. Excessive Valve Lash
14. Valve Spring Retainer Free
15. Slobber
16. Valve Lash Close-Up
17. Premature Engine Wear
18. Coolant in Engine Lubricating Oil
19. Excessive Black or Grey 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/Generator Fails To Charge
26. Alternator/Generator Charging Rate Low or Unsteady
27. Alternator/Generator Charging Rate Excessive
28. Noisy Alternator/Generator
29. BrakeSaver Not Working
30. Rack Solenoid Fails To Shut Off Engine

Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.