3406 DIESEL TRUCK ENGINE Caterpillar


Systems Operation

Usage:



Introduction

The specifications given in this book are on the basis of information available at the time the book was written. These specifications give the torques, operating pressure, measurements of new parts, adjustments and other items that will affect the service of the product.

When the words "use again" are in the description, the specification given can be used to determine if a part can be used again. If the part is equal to or within the specification given, use the part again.

When the word "permissible" is in the description, the specification given is the "maximum or minimum" tolerance permitted before adjustment, repair and/or new parts are needed.

A comparison can be made between the measurements of a worn part, and the specifications of a new part to find the amount of wear. A part that is worn can be safe to use if an estimate of the remainder of its service life is good. If a short service life is expected, replace the part.

NOTE: The specifications given for "use again" and "permissible" are intended for guidance only and Caterpillar Tractor Co. hereby expressly denies and excludes any representation, warranty or implied warranty of the reuse of any component.

Engine Design


CYLINDER AND VALVE LOCATION

Bore ... 5.40 in.(137.2 mm)

Stroke ... 6.50 in.(165.1 mm)

Number and Arrangement of Cylinders ... 6, In Line

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

No. 1 Cylinder Location ... Front

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

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

Fuel System


FUEL SYSTEM
1. Injection valve. 2. Anti-siphon block. 3. Injection pump housing. 4. Priming pump. 5. Plug. 6. Secondary filter. 7. Fuel line. 8. Return line to tank. 9. Fuel tank. 10. Primary filter. 11. Transfer pump.

This engine has a pressure type fuel system. There is a single injection pump and injection valve (1) for each cylinder. The injection pumps are in the pump housing (3) on the left side of the engine. The injection valves (1) are in the precombustion chambers or adapters under the valve cover.

The transfer pump (11) pulls fuel from the fuel tank (9) through the primary filter (10) and sends it through the base of priming pump (4) and the secondary filter (6), through the anti-siphon block (2) and to the manifold of the injection pump housing. When priming pump (4) is not used, the position of fuel line (7) and plug (5) are reversed. The fuel in the manifold of the injection pump housing goes to the injection pumps. The injection pumps are in time with the engine and send fuel to the injection valves under high pressure.

Some of the fuel in the manifold is constantly sent back through the anti-siphon block (2) and through the return line (8) to the fuel tank to remove air from the system. Orifices in the anti-siphon block control the amount of fuel that goes back to the fuel tank.

The priming pump (4) is used to remove air from the fuel filter, fuel lines and components.

The transfer pump has a bypass valve and a check valve. The bypass valve (lower side) gives control to the pressure of the fuel. The extra fuel goes to the inlet of the pump.

Fuel Injection Pump Operation

Injection pump plungers (4) and lifters (8) are lifted by cams on camshaft (9) and always make a full stroke. The force of springs (5) hold the lifters (8) against the cams of the camshaft.

Fuel from fuel manifold (1) goes through inlet passage (2) in the barrel and then into the chamber above plunger (4). During injection, the camshaft cam moves plunger (4) up in the barrel. This movement will close inlet passage (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 (4) in the barrel. When the governor moves fuel rack (7), the fuel rack moves gear (6) that is fastened to the bottom of plunger (4).


CROSS SECTION OF THE HOUSING FOR THE FUEL INJECTION PUMPS
1. Fuel manifold. 2. Inlet passage in pump barrel. 3. Check valve. 4. Pump plunger. 5. Spring. 6. Gear. 7. Fuel rack. 8. Lifter. 9. Camshaft.

Fuel Injection Valve

Fuel, under high pressure from the injection pumps, is sent through the injection lines to the injection valves. The injection valves change the fuel to the correct fuel characteristic (spray pattern) for good combustion in the cylinders.

The fuel injection valves are installed in the precombustion chambers in engines equipped with precombustion chambers. An adapter takes the place of the precombustion chamber in engines equipped with direct injection. The precombustion chambers or adapters are installed in the cylinder heads.

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 is driven by the engine and has governor weights (12), governor spring (5), valve (14) and piston (15). The valve and piston are connected to fuel rack (18). The pressure oil for the governor comes from the engine oil pump. Pressure oil goes through passage (17) and around sleeve (16). 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 (12) 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).


HYDRA-MECHANICAL GOVERNOR (Typical Example Shown at Full Load Condition)
1. Collar. 2. Speed limiter plunger. 3. Lever assembly. 4. Seat. 5. Governor spring. 6. Thrust bearing. 7. Oil passage. 8. Drive gear (weight assembly). 9. Cylinder. 10. Bolt. 11. Spring seat. 12. Governor weights. 13. Spring. 14. Valve. 15. Piston. 16. Sleeve. 17. Oil passage. 18. Fuel rack.

Governor valve (14) 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 (12) will get slower. (The governor weights will move toward each other.) Governor spring (5) moves valve (14) forward (toward the right in picture shown). When valve (14) moves forward, an oil passage around valve (14) opens to pressure oil. Oil now flows through passage (7) and fills the chamber behind piston (15) (the rear end of the valve stops oil flow through the rear of the cylinder, around the valve). 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.

When there is a reduction in engine load, there will be an increase in engine rpm and the rotation of governor weights (12) will get faster. This will move valve (14) backwards (toward the left in picture shown). This movement stops oil flow from the forward passage through piston (15) and allows the oil behind the piston to go out through a passage at the rear of the piston, around valve (14). Now, the pressure oil between sleeve (16) and piston (15) 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).

When engine rpm is at LOW IDLE, a spring-loaded plunger in lever assembly (3) comes in contact with a shoulder on the adjustment screw for low idle. To stop the engine, pull back on the governor control. This will let the spring-loaded plunger move over the shoulder on the low idle adjusting screw and move the fuel rack to the fuel closed position. With no fuel to the engine cylinders, the engine will stop.

After the engine has stopped, spring (13) moves valve (14) and piston (15) 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.

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.

In earlier engines, when the governor control is moved to fuel-on position to start the engine, plunger (2) of the speed limiter puts a restriction on the movement of lever assembly (3). After oil pressure of the engine gets to a safe level, plunger (2) of the speed limiter moves back (out of the way) and the governor control can be moved to increase engine rpm. Later engines do not have a speed limiter.

A small force from spring (13) moves fuel rack (18) to give a little more fuel for engine start. With the engine running, the rotation of governor weights (12) will put spring (13) in compression and cause fuel rack (18) to move back. (Spring (13) is extended only when the engine is stopped or at start.) When the engine is running, spring (13) is in compression.

Hydraulic Air-Fuel Ratio Control

The hydraulic air-fuel ratio control automatically controls the amount of travel of the fuel rack, in the FUEL-ON direction, until the air pressure in the inlet manifold is high enough to give complete combustion.

The hydraulically operated fuel ratio control has two valves (7 and 13). A hose assembly connects inlet air chamber (6) to the inlet manifold. Air pressure from the inlet manifold works against diaphram (5) which moves valve (13) to control oil pressure against valve (7). Engine oil pressure works against valve (7) to control movement of the fuel rack.

When the engine is stopped, there is no pressure on either of the valves. Springs (11 and 12) move both valves to the ends of their travel. In this position, there is no restriction to fuel rack movement. Also in this position, oil outlet passage (2) is open to let oil away from valve (7).


AIR-FUEL RATIO CONTROL (Engine Stopped)
1. Fuel rack linkage. 2. Oil outlet. 3. Oil inlet. 4. Pressure oil chamber. 5. Diaphram assembly. 6. Inlet air chamber. 7. Valve. 8. Small oil passages. 9. Large oil passages. 10. Oil drains. 11. Spring. 12. Spring. 13. Valve.

When the engine is started, engine oil flows through oil inlet (3) into pressure oil chamber (4), through large oil passages (9) to inside of valve (7), and out small oil passages (8) to oil outlet passage (2). Oil outlet passage (2) prevents oil pressure against valve (7) until air pressure from the inlet manifold is high enough to move valve (13) to close large oil passages (9). The control will not activate until there is some boost (inlet air pressure) available from the inlet manifold. This boost is made by the turbocharger when a load is applied during engine acceleration.


AIR-FUEL RATIO CONTROL (Engine Started)
4. Pressure oil chamber. 5. Diaphram assembly. 6. Inlet air chamber. 7. Valve. 9. Large oil passages. 11. Spring. 13. Valve.

As the inlet air pressure increases, it causes diaphram assembly (5) to move left against spring (12). Valve (7), connected to diaphram assembly (5), also moves left to close large oil passages (9). With these passages closed, chamber (4) is now charged with pressure oil, and valve (7) is pushed to the right against spring (11). The control is now activated, and will continue to operate until the engine is stopped. In the activated position, excess oil will go out pressure oil chamber (4) through large oil passages (9) past the land of valve (13) and then out through oil drains (10).


AIR-FUEL RATIO CONTROL (Control Activated)
1. Fuel rack linkage. 4. Pressure oil chamber. 5. Diaphram assembly. 6. Inlet air chamber. 7. Valve. 8. Small oil passages. 9. Large oil passages. 10. Oil drains. 13. Valve.

When the governor control is moved to increase fuel to the engine with the control activated, valve (7) limits the movement of fuel rack linkage (1) in the FUEL-ON direction. Charged oil pressure chamber (4) acts as a restriction to the movement of valve (7) until inlet air pressure increases.

As inlet air pressure increases, valve (7) moves to the left [away from springs (11 and 12)] and lets pressure oil from chamber (4) drain through large oil passages (9) past the land of valve (13), through inside of valve (7), and out through oil drains (10). This reduction of oil pressure behind the piston of valve (7) lets spring (12) move valve (7) to the left so that fuel rack linkage (1) can move gradually to increase fuel to the engine. The control is designed not to let the fuel increase until the air pressure in the inlet manifold is high enough for complete combustion. This prevents large amounts of black exhaust smoke caused by an air-fuel mixture with too much fuel.


AIR-FUEL RATIO CONTROL (Engine Acceleration)
1. Fuel rack linkage. 4. Pressure oil chamber. 5. Diaphram assembly. 6. Inlet air chamber. 7. Valve. 9. Large oil passages. 10. Oil drains. 11. Spring. 12. Spring. 13. Valve.

These movements of the control take a very small amount of time. No change in engine acceleration (rate at which speed increases) can be felt.

Automatic Timing Advance Unit


AUTOMATIC TIMING ADVANCE UNIT (Earlier Engines)
1. Flange. 2. Weight. 3. Springs. 4. Slide. 5. Drive gear. 6. Drive shaft.

The automatic timing advance unit is installed on the front of the drive shaft (6) for the fuel injection pump and is gear driven through the timing gears. The drive gear (5) for the fuel injection pump is connected to the drive shaft for the fuel injection pump through a system of weights (2), springs (3), slides (4) and a flange (1). Two slides that are fastened to the flange fit into notches made on an angle in the weights. As centrifugal force (rotation) moves the weights outward against spring pressure, the movement of the notches in the weights causes the slides to make the flange turn through a small angle in relation to the gear. Since the flange is connected to the drive shaft for the fuel injection pump, the fuel injection timing is also changed. The automatic timing advance unit on earlier engines is held in place on the drive shaft (6) by one bolt. The automatic timing advance unit on later engines is held in place on the drive shaft (6) by four bolts.


AUTOMATIC TIMING ADVANCE UNIT (Later Engines)
1. Flange. 2. Weight. 3. Springs. 4. Slide. 5. Drive gear. 6. Drive shaft.

Different units are used for the "DI" engine and the "PC" engine. No adjustment can be made to these automatic timing advance units.

Air Inlet And Exhaust System


AIR FLOW SCHEMATIC
1. Exhaust manifold. 2. Aftercooler. 3. Pipe. 4. Engine cylinder. 5. Exhaust outlet from turbocharger. 6. Turbine side of turbocharger. 7. Compressor side of turbocharger. 8. Air inlet to turbocharger.

The air inlet and exhaust system components are the air cleaner, turbocharger, inlet manifold or aftercooler, cylinder head, valves and valve system components, piston and cylinder, and exhaust manifold.

The components of the air inlet and exhaust system control the quality and the amount of air available for combustion. Outside air is pulled thru the air cleaner by the compressor wheel in compressor side of turbocharger (7). The compressor wheel compresses the clean air and forces it thru pipe (3) to the inlet manifold (or aftercooler). The air is then forced into the cylinder head to fill the inlet ports. Air flow from the inlet port into the cylinder is controlled by the intake valves.

There are two intake and two exhaust valves for each cylinder. Make reference to Valve System Components. Intake valves open when the piston moves down on the inlet stroke. When the intake valves open, cooled compressed air from the inlet port is pulled into the cylinder. The intake valves close and the piston begins to move up on the compression stroke. The air in the cylinder is compressed. When the piston is near the top of the compression stroke, fuel is injected into the precombustion chamber above the cylinder on PC engines, or directly into the cylinder on DI engines. The fuel mixes with the air and combustion starts. The force of combustion pushes the piston down on the power stroke. When the piston moves up again, it is on the exhaust stroke. The exhaust valves open, and the exhaust gases are pushed through the exhaust port into the exhaust manifold. After the piston makes the exhaust stroke, the exhaust valves close and the cycle (inlet, compression, power, exhaust) starts again.


AIR INLET AND EXHAUST SYSTEM
1. Exhaust manifold. 2. Aftercooler/Inlet manifold. 5. Exhaust outlet. 6. Turbine side of turbocharger. 7. Compressor side of turbocharger. 8. Air inlet. 9. Exhaust valve. 10. Intake valve.

Exhaust gases from exhaust manifold (1) enter turbine side of the turbocharger (6) and cause the turbine wheel to turn. The turbine wheel is connected to the shaft which drives the compressor wheel. Exhaust gases from the turbocharger pass through the exhaust outlet pipe, the muffler and the exhaust stack.


AIR INLET AND EXHAUST SYSTEM
1. Exhaust manifold. 3. Pipe. 5. Exhaust outlet from turbocharger. 6. Turbine side of turbocharger. 7. Compressor side of turbocharger. 8. Air inlet to turbocharger.

Aftercooler

Some engines have an aftercooler (1) installed in place of the inlet manifold. The aftercooler has a coolant charged core assembly. Coolant from the water pump flows through coolant inlet (3) into the aftercooler. Coolant flows through the core assembly and out of the aftercooler through coolant outlet (4) into the rear of the cylinder block.

Inlet air from the compressor side of the turbocharger is forced into the aftercooler through air inlet pipe (2). The air passes over the core assembly which lowers the air temperature to approximately 200°F (93°C). The cooler air goes out the bottom of the aftercooler into the cylinder head. The advantage of the cooler air is greater combustion efficiency.


AIR INLET SYSTEM
1. Aftercooler. 2. Air inlet pipe. 3. Coolant inlet. 4. Coolant outlet.

Turbocharger

The turbocharger (3) is installed on the center section of the exhaust manifold (2). All the exhaust gases from the engine go through the turbocharger. The compressor side of the turbocharger is connected to the inlet manifold (or aftercooler) by pipe (1).

The exhaust gases go into turbine housing (12) through exhaust inlet (19) and push the blades of turbine wheel (6). The turbine wheel is connected by a shaft to compressor wheel (5).


TURBOCHARGER
1. Pipe. 2. Exhaust manifold. 3. Turbocharger.

Clean air from the air cleaners is pulled through the compressor housing air inlet (4) by the rotation of compressor wheel (5). The action of the compressor wheel blades causes a compression of the inlet air. This compression gives the engine more power because it makes it possible for the engine to burn more air and fuel during combustion.


TURBOCHARGER (Typical Example)
4. Air Inlet. 5. Compressor wheel. 6. Turbine wheel. 7. Exhaust outlet. 8. Compressor housing. 9. Thrust bearing. 10. Sleeve. 11. Oil 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.

When the load on the engine increases, more fuel is injected into the cylinders. This makes more exhaust gases, and will cause the turbine and compressor wheels of the turbocharger to turn faster. As the compressor wheel turns faster, more air is forced into the engine. The increased flow of air gives the engine more power because it makes it possible for the engine to burn the additional fuel with greater efficiency.

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.


NOTICE

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. Damage will result when increased heat and/or friction, due to the higher engine output, goes beyond the engine cooling and lubrication systems abilities.


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.

Bearings (16 and 18) for the turbocharger use engine oil under pressure for lubrication. The oil comes in through the oil inlet port (11) and goes through passages in the center section for lubrication of the bearings. Oil from the turbocharger goes out through the oil outlet port (17) in the bottom of the center section and goes back to the engine lubrication system.

Valves And Valve System Components

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


VALVE SYSTEM COMPONENTS
1. Intake bridge. 2. Intake rocker arm. 3. Push rod. 4. Rotocoil. 5. Valve spring. 6. Valve guide. 7. Intake valves. 8. Lifter. 9. Camshaft.

The intake and exhaust valves are opened and closed by movement of these components: crankshaft, camshaft, lifters, push rods, rocker arms, bridges, 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 front of the crankshaft. As camshaft (9) turns, the cams of the camshaft also turn and cause lifters (8) to go up and down. This movement makes push rods (3) move rocker arms (2 and 10). Movement of the rocker arms will make intake and exhaust bridges (1 and 11) move up and down on dowels mounted in the cylinder head.

These bridges let one rocker arm open, or close, two valves (intake or exhaust) at the same time. There are two intake and two exhaust valves in each cylinder. One valve spring (5) for each valve holds the valves in the closed position when the lifters move down.


VALVE SYSTEM COMPONENTS
1. Intake bridge. 2. Intake rocker arm. 7. Intake valves. 10. Exhaust rocker arm. 11. Exhaust bridge. 12. Exhaust valves.

Rotocoil assemblies (4) cause the valves to have rotation while the engine is running. This rotation of the valves keeps the deposit of carbon on the valves to a minimum and gives the valves longer service life.

Lubrication System

Engine Without Brakesaver


LUBRICATION SYSTEM COMPONENTS
1. Oil return line from turbocharger. 2. Oil supply line to turbocharger. 3. Oil manifold in cylinder block. 4. Oil cooler. 5. Oil filter. 6. Oil pan.

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 the oil pan (6) through the suction bell (9) to the oil pump (7). The oil pump sends warm oil to the oil cooler (10) and then to the oil filter (4). From the oil filter, oil is sent to the oil manifold (1) in the cylinder block and to the oil supply line (2) for the turbocharger. Oil from the turbocharger goes back through the oil return line (3) to the oil pan.

With the engine cold (starting conditions), oil comes from the oil pan (6) through the suction bell (9) to the oil pump (7). When the oil is cold, an oil pressure difference in the bypass valve (installed in the oil filter housing) causes the valves to open. These bypass valves give immediate lubrication to all components when cold oil with high viscosity causes a restriction to the oil flow through the oil cooler (10) and oil filter (4). The oil pump then sends the cold oil through the bypass valve (8) for the oil cooler and through the bypass valve (5) for the oil filter to the oil manifold (1) in the cylinder block and to the supply line (2) for the turbocharger. Oil from the turbocharger goes back through the oil return line (3) to the oil pan.

When the oil gets warm, the pressure difference in the bypass valves decrease and the bypass valves close. Now there is a normal oil flow through the oil cooler and oil filter.


FLOW OF OIL (ENGINE WARM)
1. Oil manifold in cylinder block. 2. Oil supply line to turbocharger. 3. Oil return line from turbocharger. 4. Oil filter. 5. Bypass valve for the oil filter. 6. Oil pan. 7. Oil pump. 8. Bypass valve for the oil cooler. 9. Suction bell. 10. Oil cooler.

The bypass valves will also open when there is a restriction in the oil cooler or oil filter. This action does not let an oil cooler or oil filter with a restriction prevent the lubrication of the engine.


FLOW OF OIL (ENGINE COLD)
1. Oil manifold in cylindr block. 2. Oil supply line to turbocharger. 3. Oil return line from turbocharger. 4. Oil filter. 5. Bypass valve for the oil filter. 6. Oil pan. 7. Oil pump. 8. Bypass valve for the oil cooler. 9. Suction bell. 10. Oil cooler.

Engine With Brakesaver


LUBRICATION SYSTEM COMPONENTS
1. Oil return line from turbocharger. 2. Oil supply line to turbocharger. 3. Oil manifold in cylinder block. 4. Oil cooler. 5. Oil filter. 6. Oil pan.

The lubrication system has the following components: oil pan, two section oil pump, oil cooler, oil filter, oil lines to and from the turbocharger and oil passages in the cylinder block. The front section of the oil pump gives oil for the lubrication of the engine. The rear section of the oil pump gives oil for the operation of the BrakeSaver. The front section of the oil pump sends oil through the oil filter and the rear section of the oil pump sends oil through the oil cooler.

Oil Flow Through the Oil Filter

With the engine warm (normal operation), oil comes from the oil pan (6) through the suction bell (8) to the front section of the oil pump (7). The front section of the oil pump sends oil to the oil filter (4). From the oil filter, oil is sent to the oil manifold (1) in the cylinder block and to the oil supply line (2) for the turbocharger. Oil from the turbocharger goes back through the oil return line (3) to the oil pan.

With the engine cold (starting conditions), oil comes from the oil pan (6) through the suction bell (8) to the front section of the oil pump (7). When the oil is cold, an oil pressure difference in the bypass valve (5) (installed in the oil filter housing) causes the valve to open. This bypass valve gives immediate lubrication to all components when cold oil with high viscosity causes a restriction to the oil flow through the oil filter (4). The front section of the oil pump then sends the cold oil through the bypass valve (5) for the oil filter to the oil manifold (1) in the cylinder block and to the supply line (2) for the turbocharger. Oil from the turbocharger goes back through the oil return line (3) to the oil pan.

When the oil gets warm, the pressure difference in the bypass valve decreases and the bypass valve closes. Now there is a normal flow through the oil filter.


FLOW OF OIL (ENGINE WARM)
1. Oil manifold in cylinder block. 2. Oil supply line to turbocharger. 3. Oil return line from turbocharger. 4. Oil filter. 5. Bypass valve for the oil filter. 6. Oil pan. 7. Oil pump (front section). 8. Suction bell.


FLOW OF OIL (ENGINE COLD)
1. Oil manifold in cylinder block. 2. Oil supply line to turbocharger. 3. Oil return line from turbocharger. 4. Oil filter. 5. Bypass valve for the oil filter. 6. Oil pan. 7. Oil pump (front section). 8. Suction bell.

The bypass valve will also open when there is a restriction in the oil filter. This action does not let an oil filter with a restriction prevent the lubrication of the engine.

Oil Flow Through the Oil Cooler

With the engine warm (normal operation), oil comes from the oil pan (6) through the suction bell (7) to the rear section of the oil pump (5). The rear section of the oil pump sends warm oil to the BrakeSaver control valve (3). If the BrakeSaver control valve is in the OFF position, it sends the warm oil to the oil cooler (1) where it is made cool. From the oil cooler, the cool oil goes back through the BrakeSaver control valve to the engine oil pan (6).


FLOW OF OIL WITH BRAKESAVER OFF (ENGINE WARM)
1. Oil cooler. 2. Bypass valve for the oil cooler. 3. BrakeSaver control valve. 4. BrakeSaver. 5. Oil pump (rear section). 6. Oil pan. 7. Suction bell.

If the BrakeSaver control valve (3) is in the ON position, the oil from the rear section of the oil pump (5) that goes to the BrakeSaver control valve is now sent to the BrakeSaver (4). After the oil goes through the BrakeSaver, it goes back to the BrakeSaver control valve. The control valve now sends the warm oil to the oil cooler (1) where it is made cool. From the oil cooler, the cool oil goes back through the BrakeSaver control valve to the engine oil pan (6).


FLOW OF OIL WITH BRAKESAVER ON (ENGINE WARM)
1. Oil cooler. 2. Bypass valve for the oil cooler. 3. BrakeSaver control valve. 4. BrakeSaver. 5. Oil pump (rear section). 6. Oil pan. 7. Suction bell.

When the engine is cold (starting conditions), the oil has a high viscosity. This high viscosity causes a restriction to the oil flow through the oil cooler (1). When there is a restriction in the oil cooler, an oil pressure difference in the bypass valve (2) causes the valve to open. When the bypass valve is open, oil from the rear section of the oil pump (5) can go through the valve and drain back into the engine oil pan (6).


FLOW OF OIL WITH BRAKESAVER OFF (ENGINE COLD)
1. Oil cooler. 2. Bypass valve for the oil cooler. 3. BrakeSaver control valve. 4. BrakeSaver. 5. Oil pump (rear section). 6. Oil pan. 7. Suction bell.

Oil Flow In The Engine (Later)


ENGINE OIL FLOW SCHEMATIC

1. Bracket for rocker arm shaft.

2. Rocker arm shaft.

3. Oil passage to lifters.

4. Valve lifter bore.

5. Oil supply rocker shaft bracket.

6. Rocker arm shaft.

7. Oil supply rocker shaft bracket.

8. Oil passage to accessory drive.

9. Oil passage to rocker shaft bracket.

10. Oil passage to idler gear shaft.

11. Oil passage to rocker shaft bracket.

12. Oil passage to the fuel injection pump and governor.

13. Camshaft bearing.

14. Oil jet tubes.

15. Main bearing.

16. Oil manifold.

17. Oil passage from the oil pump to the oil cooler and filter.

18. Oil passage from the oil cooler and filter.

From the oil manifold (16) in the cylinder block, oil is sent through drilled passages in the cylinder block that connect the main bearings (15) and the camshaft bearings (13). Oil goes through drilled holes in the crankshaft to give lubrication to the connecting rod bearings. A small amount of oil is sent through oil jet tubes (14) to make the pistons cooler. Oil goes through grooves in the bores for the front and rear camshaft bearings and then into oil passages (3) that connects the valve lifter bores (4). These passages give oil under pressure for the lubrication of the valve lifters.

Oil is sent from lifter bores (4) through passage (11) to an oil passage in bracket (5) (next to cylinder No. 4.) to supply pressure lubrication to rear rocker arm shaft (2). Oil is also sent from front lifter bore through passage (9) to an oil passage in front bracket (7) for front rocker arm shaft (6). Holes in the rocker arm shafts lets the oil give lubrication to the valve system components in the cylinder head.

The air compressor gets oil from passage (8) in the cylinder block, through passages in the timing gear housing and the accessory drive gear.

The idler gear gets oil from passage (10) in the cylinder block through a passage in the shaft for the idler gear installed on the front of the cylinder block.

The fuel injection pump and governor gets oil from passage (12) in the cylinder block. The automatic timing advance unit gets oil from the fuel injection pump through the drive shaft for the fuel injection pump.

There is a pressure control valve in the oil pump. This valve controls the pressure of the oil coming 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 goes up and the valve will open. This allows the oil that is not needed to go back to the inlet oil passage of the oil pump.

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

Oil Flow In The Engine (Earlier)


ENGINE OIL FLOW SCHEMATIC

1. Bracket for the rocker arm shaft.

2. Rocker arm shaft.

3. Oil passage to valve lifters.

4. Valve lifter bore.

5. Rocker arm shaft.

6. Bracket for the rocker arm shaft.

7. Oil passage to head and accessory drive.

8. Oil passage to head.

9. Oil passage to idler gear shaft.

10. Oil passage to head.

11. Oil passage to the fuel injection pump and governor.

12. Oil passage to head.

13. Camshaft bearing.

14. Orifice to make piston cooler.

15. Main bearing.

16. Oil manifold.

17. Oil passage from the oil pump to the oil cooler and filter.

18. Oil passage from the oil cooler and filter.

From the oil manifold (16) in the cylinder block, oil is sent through drilled passages in the cylinder block that connect the main bearings (15) and the camshaft bearings (13). Oil goes through drilled holes in the crankshaft to give lubrication to the connecting rod bearings. A small amount of oil is sent through orifices (14) near the main bearings to make the pistons cooler. Oil goes through grooves in the bores for the front and rear camshaft bearings and then into oil passages (3) that connects the valve lifter bores (4). These passages give oil under pressure for the lubrication of the valve lifters.

Oil is sent through passages (12) and (10) to the mounting hole for the rear bracket (1) for the rocker arm shaft. Oil is also sent through passages (8) and (7) to the mounting hole for the front bracket (6) for the rocker arm shaft. Then oil goes up the mounting holes for the front and rear brackets for the rocker arm shaft and into the rocker arm shafts (2) and (5). Holes in the rocker arm shafts lets the oil give lubrication to the valve system components in the cylinder head.

The air compressor gets oil from passage (7) in the cylinder block, through passages in the timing gear housing and the accessory drive gear.

The idler gear gets oil from passage (9) in the cylinder block through a passage in the shaft for the idler gear installed on the front of the cylinder block.

The fuel injection pump and governor gets oil from passage (11) in the cylinder block. The automatic timing advance unit gets oil from the fuel injection pump through the drive shaft for the fuel injection pump.

There is a bypass valve in the oil pump. This bypass valve controls the pressure of the oil coming 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 goes up and the bypass valve will open. This allows the oil that is not needed to go back to the inlet oil passage of the oil pump.

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

Cooling System

This engine has a pressure type cooling system equipped with a shunt line (5).

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 (5) gives several advantages. The shunt line gives a positive pressure of coolant at the water pump inlet to prevent cavitation. The shunt line lets air in the cooling system go out of the coolant through the vent tube (4) 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.


COOLING SYSTEM (ENGINE WARM)
1. Cylinder head. 2. Water temperature regulator. 3. Outlet hose. 4. Vent tube. 5. Shunt line. 6. Water elbow. 7. Water pump. 8. Cylinder block. 9. Oil cooler. 10. Inlet hose. 11. Radiator.

In normal operation (engine warm) the water pump (7) sends coolant through the oil cooler (9) and into the cylinder block (8). Coolant moves through the cylinder block into the cylinder head (1) and then goes to the housing for the temperature regulator (2). The temperature regulator is open and the coolant goes through the outlet hose (3) to the radiator (11). 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 (10) and into the water pump.

NOTE: The water temperature regulator (2) is an important part of the cooling system. It divides coolant flow between radiator (11) and bypass [water elbow(6)] as necessary to maintain the correct temperature. If the water temperature regulator is not installed in the system, there is no mechanical control, and most of the coolant will take the path of least resistance thru the bypass. This will cause the engine to overheat in hot weather. In cold weather, even the small amount of coolant that goes thru the radiator is too much, and the engine will not get to normal operating temperatures.

A small amount of coolant is moving constantly through the vent tube (4) 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 (5) to the inlet of the water pump.

When the engine is cold, the water temperature regulator (2) 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 (7) through water elbow (6).

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 comes out of the bonnet (1) for the oil cooler and goes through tube (2) to the aftercooler (3). This coolant goes through the aftercooler and out elbow (4) and back into the cylinder block.


COOLANT FLOW TO AFTERCOOLER
1. Oil cooler bonnet. 2. Tube to aftercooler.


COOLANT FLOW FROM AFTERCOOLER
3. Aftercooler. 4. Elbow.

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.

Coolant For Air Compressor

The coolant for the air compressor (2) comes from the cylinder block through inlet hose (3) and into the air compressor. The coolant goes from the air compressor through outlet hose (1) back into the front of the cylinder head.


COOLANT FLOW IN AIR COMPRESSOR
1. Outlet hose. 2. Air compressor. 3. Inlet hose.

Coolant Conditioner (An Attachment)


COOLING SYSTEM WITH COOLANT CONDITIONER
1. Cylinder liner. 2. Coolant bypass line. 3. Coolant outlet (to radiator). 4. Radiator. 5. Temperature regulator. 6. Water pump. 7. Coolant conditioner element. 8. Engine oil cooler. 9. Coolant inlet (from radiator).

Some conditions of operation have been found to cause pitting (small holes in the metal surface) from corrosion or cavitation erosion (wear caused by air bubbles in the coolant) on the outer surface of the cylinders liners and the inner surface of the cylinder block next to the liners. The addition of a corrosion inhibitor (a chemical that gives a reduction of pitting) can keep this type of damage to a minimum.

The "spin-on" coolant conditioner elements, similar to the fuel filter and oil filter elements, fasten to a base that is mounted on the engine or is remote mounted. Coolant flows thru lines from the oil cooler bonnet to the base, thru the element, and back to the water pump or to the air compressor (if so equipped). There is a constant flow of coolant thru the element.

The element has a specific amount of inhibitor for acceptable cooling system protection. As coolant flows thru the element, the corrosion inhibitor, which is dry material, dissolves (goes into solution) and mixes to the correct concentration. Two basic types of elements are used for the cooling system, and they are called the "PRECHARGE" and the "MAINTENANCE" elements. Each type of element has a specific use and must be used correctly to get the necessary concentration for cooling system protection.

The "PRECHARGE" element has more than the normal amount of inhibitor, and is used when a system is first filled with new coolant (unless Dowtherm 209 Antifreeze is used). This element has to add enough inhibitor to bring the complete cooling system up to the correct concentration.

The "MAINTENANCE" elements have a normal amount of inhibitor. They are installed at the first change interval and provide enough inhibitor to keep the corrosion protection at an acceptable level. After the first change period, only "MAINTENANCE" elements are installed at specified intervals to give protection to the cooling system.

If Dowtherm 209 Antifreeze is used when a cooling system is first filled with new coolant, only a "MAINTENANCE" element should be used. The "PRECHARGE" element is not necessary.

Electrical System

The electrical system can have three separate circuits: the charging circuit, the starting circuit and the low amperage circuit. Some of the electrical system components are used in more than one circuit. The battery (batteries), circuit breaker, ammeter, cables and wires from the battery are all common in each of the circuits.

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 start switch is activated.

The starting circuit of a "PC" engine can have a glow plug for each cylinder. Glow plugs are small heating units in the precombustion chambers. Glow plugs make ignition of the fuel easier when the engine is started in cold temperature.

The low amperage circuit and the charging circuit are both connected through the ammeter. The starting circuit is not connected through the ammeter.

Charging System Components

Alternator

The alternator is driven by V-type belts from the crankshaft pulley. This alternator is a three phase, self-rectifying charging unit, and the regulator is part of the alternator.

This alternator design has no need for slip rings or brushes, and the only part that has movement is the rotor assembly. All conductors that carry current are stationary. The conductors are: the field winding, stator windings, six rectifying diodes, and the regulator circuit components.

The rotor assembly has many magnetic poles like finger with air space between each opposite pole. The poles have residual magnetism (like permanent magnets) that produce a small amount of magnet-like lines of force (magnetic field) between the poles. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings from the small magnetic lines of force made by the residual magnetism of the poles. This AC current is changed to direct current (DC) when it passes through the diodes of the rectifier bridge. Most of this current goes to charge the battery and to supply the low amperage circuit, and the remainder is sent on to the field windings. The DC current flow through the field windings (wires around an iron core) now increases the strength of the magnetic lines of force. These stronger lines of force now increase the amount of AC current produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator.

The voltage regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system and switches on and off many times a second to control the field current (DC current to the field windings) for the alternator to make the needed voltage output.


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.



DELCO-REMY ALTERNATOR
1. Regulator. 2. Roller bearing. 3. Stator winding. 4. Ball bearing. 5. Rectifier bridge. 6. Field winding. 7. Rotor assembly. 8. Fan.

Starting Circuit Components

Solenoid

A solenoid is a magnetic switch that uses low current to close a high current circuit. The solenoid has an electromagnet with a core (6) which moves.

There are contacts (4) on the end of core (6). The contacts are held in the open position by spring (5) that pushes core (6) from the magnetic center of coil (1). Low current will energize coil (1) and make a magnetic field. The magnetic field pulls core (6) to the center of coil (1) 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.

Starting Motor

The starting motor is used to turn the engine flywheel fast enough to get the engine running.


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

The starting motor has a solenoid. When the start switch is turned to the ON position, the solenoid will be activated electrically. The solenoid core will now move to push the starter pinion, by a mechanical linkage, to engage with the ring gear on the flywheel of the engine. The starter pinion will engage with the ring gear before the electric contacts in the solenoid close the circuit between the battery and the starting motor. When the circuit between the battery and the starting motor is complete, the pinion will turn the engine flywheel. A clutch gives protection for the starting motor so that the engine, when it starts to run, can not turn the starting motor too fast. When the start switch is released, the starter pinion will move away from the flywheel ring gear.

Shutoff Solenoid

The rack shutoff solenoid, when activated, moves the shutoff lever in the governor housing which in turn moves the fuel rack to the fuel closed position. The solenoid is activated (or deactivated) by the ignition switch in the cab of the truck.

Wiring Diagrams

12 Volt Starting System

NOTE: Numbers with arrow to wire show wire size.


12 VOLT START WITH NO GLOW PLUGS
1. Ammeter. 2. Lights. 3. Key Switch. 4. Gauges. 5. Shut-off solenoid. 6. Momentary switch. 7. Alternator. 8. Starting motor. 9. Switch. 10. Battery (12 volt).


12 VOLT START WITH GLOW PLUGS
1. Ammeter. 2. Lights. 3. Key switch. 4. Gauges. 5. Momentary switch. 6. Shut-off solenoid. 7. Alternator. 8. Heat-start switch. 9. Switch. 10. Battery (12 volt). 11. Starting motor. 12. Switch. 13. Glow plugs.

24 Volt Starting System

System has two 12 volt batteries and a series-parallel switch.

NOTE: Numbers with arrow to wire show wire size.


24 VOLT START WITH NO GLOW PLUGS
1. Ammeter. 2. Lights. 3. Key switch. 4. Gauges. 5. Alternator. 6. Momentary switch. 7. Series-parallel switch. 8. Shut-off solenoid. 9. Starting motor (24 volt). 10. Battery (12 volt). 11. Battery (12 volt).


24 VOLT START WITH GLOW PLUGS
1. Ammeter. 2. Lights. 3. Key switch. 4. Gauges. 5. Alternator. 6. Momentary switch. 7. Series-parallel switch. 8. Shut-off solenoid. 9. Heat-start switch. 10. Starting motor (24 volt). 11. Switch. 12. Glow plugs. 13. Battery (12 volt). 14. Battery (12 volt).


CONTACT ARRANGEMENT FOR SERIES-PARALLEL SWITCH

NOTE: The series-parallel switch shown can be any of the switches given below.

11198451119899199647419964771996481

For any other switch, make reference to instructions with the switch to get correct terminal connections.

Brakesaver

The BrakeSaver permits the operator to control the speed reduction of the vehicle on grades, curves, or at any time when speed reduction is necessary but long applications of the service brakes are not desired.


ENGINE WITH BRAKESAVER (RIGHT SIDE)


ENGINE WITH BRAKESAVER (LEFT SIDE)

Brakesaver Components

The BrakeSaver housing (3) is fastened directly to the rear face of the flywheel housing (1). The BrakeSaver adds approximately four inches to the length of the engine drive train. A rotor (2) and a ring gear plate (6) are installed between the rear flange of the crankshaft (5) and the flywheel (4). The ring gear plate (6) permits the use of the standard engine starting motor. The rotor turns in a space between the stator (7) and the BrakeSaver housing (3).


BRAKESAVER COMPONENTS
1. Flywheel housing. 2. Rotor. 3. BrakeSaver housing. 4. Flywheel. 5. Crankshaft flange. 6. Ring gear plate. 7. Stator.

The engine oil pump has two sections. The front section (14) of the oil pump gives oil to the engine for lubrication. The rear section (8) of the oil pump sends engine oil through the BrakeSaver control valve (16) to the BrakeSaver (9). The rear section of the oil pump also sends oil through line (17) to the engine oil cooler (not shown). From the oil cooler, the cool oil goes through line (18), through the baffle (13) and back into the engine oil pan (15).

When the BrakeSaver is turned off, tube (10) lets the oil in the BrakeSaver rapidly go out of the BrakeSaver and back into the engine oil pan.

When the engine is cold (starting conditions), the oil has a high viscosity. This high viscosity causes a restriction to the oil flow through the oil cooler. When there is a restriction in the oil cooler, an oil pressure difference in the bypass valve (12) causes the valve to open. When the bypass valve is open, oil from the rear section of the oil pump can go through hole (11) in the bypass valve (12) and drain back into the engine oil pan (15).


BRAKESAVER COMPONENTS
8. Oil pump (rear section). 9. BrakeSaver. 10. Tube. 11. Hole. 12. Bypass valve. 13. Baffle. 14. Oil pump (front section). 15. Engine oil pan. 16. BrakeSaver control valve. 17. Line. 18. Line.

Brakesaver Lubrication

Piston ring seals (3) and (6) keep pressure oil in the chamber (5) around the rotor during operation. Lip-type seals (7) and (8) prevent oil leakage from the BrakeSaver. An outside oil line (1) from the engine lubrication system sends engine oil to the BrakeSaver housing. Orifices (2) and (4) in the BrakeSaver send oil to a space between the lip seals and the piston-type ring seals at a rate of .33 U.S. gpm (1.24 liter/min). This oil gives lubrication to the seals under all conditions of operation.

The spaces between the lip-type seals and the piston-type ring seals are connected to an outside drain line (9) that lets the oil go back to the engine oil pan.


BRAKESAVER LUBRICATION
1. Oil line. 2. Orifice. 3. Piston-type ring seal. 4. Orifice. 5. Chamber. 6. Piston ring seal. 7. Lip-type seal. 8. Lip-type seal. 9. Oil line.

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 (5) is fastened to and turns with the engine crankshaft. The rotor has pockets (4) on the outer circumference of both sides and four holes (3) to permit equal oil flow to both sides of the rotor.

The BrakeSaver housing (1) and the stator are fastened to the flywheel housing and can not turn. Both the BrakeSaver housing and the stator have pockets (2) on their inside surfaces in alignment with the pockets (4) in the motor.


BRAKESAVER HOUSING AND ROTOR
1. BrakeSaver housing. 2. Pockets. 3. Hole. 4. Pocket. 5. Rotor.

The rotor (5) turns in the compartment made by the stator (6) and the BrakeSaver housing (1). When the BrakeSaver housing is in operation, engine oil comes into this compartment near the center through a passage from the bottom 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 (4) send it into the pockets (2) of the stator and BrakeSaver housing. As the rotor turns and the oil flows around the BrakeSaver compartment, it takes the shape of a spiral.

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.


OIL FLOW THROUGH BRAKESAVER
1. BrakeSaver housing. 2. Pocket. 4. Pocket. 5. Rotor. 6. Stator.

As the BrakeSaver inlet passage opens, more oil starts to flow in a spiral shape between the rotor and the stator. Inside this spiral flow (7) of oil is an air pocket (8). 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.

When the BrakeSaver is in operation, the level of braking can be controlled by the inlet oil pressure, since the braking force available is in direct relation to the amount of oil that is 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.


OIL FLOW IN BRAKESAVER
1. BrakeSaver housing. 5. Rotor. 6. Stator. 7. Spiral flow. 8. Air pocket.

Brakesaver Control


BRAKESAVER OIL FLOW (OFF)
1. BrakeSaver control lever. 2. Oil cooler. 3. Valve spool. 4. BrakeSaver control valve. 5. Oil pump. 6. BrakeSaver. 7. Line. 8. Oil pan.

When the BrakeSaver control lever (1) is in the OFF position, spring force holds the valve spool (3) against the cover at the air inlet end of the control valve (4). With the valve spool (3) in this position, the oil pump (5) sends engine oil from the oil pan (8) through the control valve (4) to the oil cooler (2). From the oil cooler, the oil goes through the control valve, through line (7), and back to the engine oil pan (8). With the BrakeSaver control valve in this position, no oil is sent to the BrakeSaver (6).

When the BrakeSaver control lever (1) is moved to the ON position, pressure air moves the valve spool (3) to the right against the spring force. With the valve spool in this position, engine oil from the oil pump (5) is sent through the control valve (4) to the rotor compartment of the BrakeSaver (6). From the BrakeSaver, the oil goes through the control valve, through the oil cooler (2), back through the control valve, and back into the BrakeSaver.

The oil cannot go back to the engine oil pan (8) because the passage through the control valve to line (7) is closed by the valve spool.

The time required to fill the BrakeSaver with pressure oil to the point of maximum braking in the BrakeSaver is approximately 1.8 seconds.


BRAKESAVER OIL FLOW (FILL)
1. BrakeSaver control lever. 2. Oil cooler. 3. Valve spool. 4. BrakeSaver control valve. 5. Oil pump. 6. BrakeSaver. 7. Line. 8. Oil pan.

As the BrakeSaver (6) fills, the turning rotor causes an increase in the oil pressure in the BrakeSaver. Inlet oil to the BrakeSaver and outlet oil from the BrakeSaver both go into the spring bore in the valve spool (3). The average of the inlet oil pressure and the outlet oil pressure in the spring bore plus the force of the spring work against the pressure air on the left end of the valve spool. When the force of the pressure oil plus the spring force become larger than the force of the pressure air, the valve spool moves to the left. This movement causes a restriction in the passage for the inlet oil and an oil pressure decrease in the BrakeSaver.

A decrease in rotor speed (normally with a decrease in vehicle speed) causes a decrease in the oil pressure in the BrakeSaver. This causes a decrease in oil pressure in the spring bore in the valve spool which lets the pressure air on the left end of the spool move the spool to the right. This movement farther opens the passage for the inlet oil and the oil pressure in the BrakeSaver has an increase.


BRAKESAVER OIL FLOW (OPERATE)
1. BrakeSaver control lever. 2 Oil cooler. 3. Valve spool. 6. BrakeSaver. 8. Oil pan.

An increase in rotor speed will cause an increase in the oil pressure in the BrakeSaver. This increase in oil pressure will cause the valve spool to move to the left to give a restriction to the inlet oil to the BrakeSaver.

The valve spool is constantly moving to make adjustments to the BrakeSaver inlet pressure for compensation of the changing rotor speeds caused by normal operation of the vehicle. This constant movement of the valve spool is necessary to keep the amount of braking force in the BrakeSaver at the level set by the control lever (1).

During normal operation, the outlet oil from the BrakeSaver goes to the oil cooler (2). From the oil cooler, some of the oil (approximately 60%) goes back to the BrakeSaver inlet and the remainder of the oil from the oil cooler goes to the engine oil pan (8).

When the BrakeSaver control lever (1) is moved to the OFF position, the pressure air on the left end of the valve spool (3) goes out of the control valve (4). With no pressure air in the valve, the pressure oil in the spring bore plus the spring force move the valve spool against the cover at the air inlet end of the control valve. This movement closes the BrakeSaver inlet passage. The rotor in the BrakeSaver (6) now pushes the oil out of the BrakeSaver, through the control valve, through line (9), and back to the oil pan (8).

The time required to move the oil from the BrakeSaver is approximately 1.5 seconds.

With the control valve in this position, the oil pump (5) sends oil through the oil cooler (2) and through line (7) back to the oil pan.


BRAKESAVER OIL FLOW (DRAIN)
1. BrakeSaver control lever. 2. Oil cooler. 3. Valve spool. 4. BrakeSaver control valve. 5. Oil pump. 6. BrakeSaver. 7. Line. 8. Oil pan. 9. Line.

Operator Controls

Two types of controls are available for the BrakeSaver: a manual control and an automatic control.

Manual Control

Pressure air from the truck air system is sent to the pressure reducing valve (1) where the air pressure is controlled to 50 psi (345 kPa). This controlled pressure air goes to the manual control valve (2).

When the operator moves the BrakeSaver control lever (3) toward the ON position, pressure air is sent to the BrakeSaver control valve (6). The farther the lever (3) is moved toward the ON position, the higher the pressure of the air sent to the BrakeSaver control valve. An increase in air pressure in the BrakeSaver 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 the BrakeSaver control lever (3).

When the BrakeSaver is turned off, the pressure air goes out of the system through a passage in the manual control valve (2). This lets the pressure air out of the BrakeSaver control valve (6) and removes the braking force from the BrakeSaver.

An air pressure passage gauge (4) gives the operator a relative indication of the air pressure being sent to the BrakeSaver 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 (5) 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 the BrakeSaver control lever (3) 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.



MANUAL CONTROL
1. Pressure reducing valve. 2. Manual control valve. 3. BrakeSaver control lever. 4. Air pressure gauge. 5. Oil temperature gauge. 6. BrakeSaver control valve.

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), a double check valve (7), and three switches (10), (11), and (12). The solenoid valve (8) (when activated) sends pressure air from the pressure reducing valve (1) to the BrakeSaver control valve (6). The solenoid valve is connected to three switches: mode selector switch (10), accelerator switch (11), and clutch switch (12). 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 the key switch (9) which prevents the solenoid valve from being activated when the key switch is OFF.

The mode selector switch (10) has two positions: MANUAL and AUTOMATIC-MANUAL. For automatic operation of the BrakeSaver, the mode selector switch must be in the AUTOMATIC-MANUAL position.

The clutch switch (12) is connected to the clutch linkage. When the clutch is engaged (cluth 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 (11) 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 key switch (9) opens the solenoid valve (8). When the solenoid valve is open, full air pressure [50 psi (345kPa)] is sent through the double check valve (7) to the BrakeSaver control valve (6). The double check valve keeps the pressure air from going out of the system through the manual control valve (2) when the BrakeSaver control lever (3) 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.


AUTOMATIC CONTROL
1. Pressure reducing valve. 2. Manual control valve. 3. BrakeSaver control lever. 4. Air pressure gauge. 5. Oil temperature gauge. 6. BrakeSaver control valve. 7. Double check valve. 8. Solenoid valve. 9. Key switch. 10. Mode selector switch. 11. Accelerator switch. 12. Clutch switch.

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

When the mode selector switch (10) 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 (2) or in the solenoid valve (8). This lets the pressure air out of the BrakeSaver control valve (6) and removes the braking force from the BrakeSaver.

The manual control valve (2) can be operated with the mode selector switch (10) 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 mode selector switch is in the AUTOMATIC-MANUAL position, the manual control valve will have an effect.

Jake Brake

The JAKE BRAKE permits the operator to control the speed of the vehicle on grades, curves, or anytime when speed reduction is necessary, but long applications of the service brakes are not desired. In downhill operation, or any slow down condition, the engine 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 pistons of the engine.

The JAKE BRAKE, when activated, does this through the conversion of the engine from a source of power to an air compressor that absorbs (takes) power. This conversion is made possible by a master to slave piston arrangement, where movement of the rocker arm for the exhaust valves of one cylinder is transferred hydraulically to open the exhaust valves of another cylinder near the top of its normal compression stroke cycle. The compressed cylinder charge is now released into the exhaust manifold.

The release of the compressed air pressure to the atmosphere prevents the return of energy to the engine piston on the expansion (power) stroke. The result is an energy loss, since the work done by the compression of the cylinder charge is not returned by the the expansion process. This energy loss is taken from the rear wheels, which provides the braking action for the vehicle.

Jake Brake Components


JAKE BRAKE INSTALLED
1. Rear housing. 2. Front housing. 3. Stud. 4. Support bracket.

The JAKE BRAKE consists of two different housings, one installed in each of the valve mechanism compartments above the rocker arms and rocker arm shaft. Each housing is positioned over three cylinders, and is mounted on two support brackets (4) and on two studs (3) at the end rocker shaft brackets. Special exhaust rocker arm adjusting screws and exhaust valve bridges are necessary.

NOTE: Only the engine valves and valve mechanism for the exhaust side of the cylinders are used in the operation of the JAKE BRAKE.

A spacer is used on top of the valve cover base to permit installation of the valve cover. The increase in height with the JAKE BRAKE installed is less than 2.00 in. (50.8 mm).

Both the front and rear JAKE BRAKE housings consist of the parts that follow: three master pistons, three slave pistons, three control valves, and one solenoid valve.

Jake Brake Operation

The JAKE BRAKE operates with engine oil which is supplied from the rocker arm shafts. Solenoid valve (1) controls the oil flow in the housing.

When the solenoid is activated, solenoid valve (1) moves down and closes oil drain passage (14) to oil pan (18). At the same time, it opens low pressure oil passage (15) to three control valves (3). As low pressure passage (15) is filled with engine oil, control valves (3) are pushed up in their chamber against force of spring (2). At this position, a groove in control valve (3) is in alignment with high pressure oil passage (4) that supplies slave piston (10) and master piston (6). Engine oil pressure will now lift ball check valve (9) and fill high pressure oil passage (4) and the chambers behind the slave and master pistons. This pressure moves the pistons down to a position where they will now make contact with the engine valve mechanism. When the oil pressure is the same through all the oil passages, the small spring will force ball check valve (9) back against its seat. The system is now completely charged and ready for operation with engine valve mechanism. When the solenoid is activated, the JAKE BRAKE is ready to operate in approximately 1/5 of a second.


MASTER-SLAVE CIRCUIT SCHEMATIC
1. Solenoid valve. 2. Spring. 3. Control valve. 4. High pressure oil passage. 5. Slave piston adjustment screw. 6. Master piston. 7. Rocker arm shaft oil passage. 8. Engine oil pump. 9. Ball check valve. 10. Slave piston. 11. Rocker arm. 12. Spring. 13. Rocker arm adjustment screw. 14. Oil drain passage. 15. Low pressure oil passage. 16. Exhaust valve bridge. 17. Exhaust push rod. 18. Engine oil pan. 19. Exhaust valves.

When engine push rod (17) for the exhaust valves begins to move up on its normal exhaust cycle, rocker arm (11) and adjustment screw (13) move up to make contact with master piston (6). As master piston (6) begins to move up, the oil pressure increases in passage (4) because ball check valve (9) will not let the oil out. Since there is a constant increase in pressure with the rocker arm movement, slave piston (10) is forced down against exhaust valve bridge (16) (of a different cylinder) with enough force to open exhaust valves (19).


OIL PASSAGE SCHEMATIC (Front Housing Shown)
1. Solenoid valve. 3. Control valves. 4. High pressure oil passages. 6. Master pistons. 10. Slave pistons 15. Low pressure oil passage.

This master-slave circuit is designed so that master piston (6) is only moved by an engine cylinder on the exhaust stroke, while slave piston (10) opens only the exhaust valves of an engine cylinder on the compression stroke (just before top center). The braking force is constant, and the sequence is the same as the firing order of the engine, as shown in the chart that follows:

When solenoid valve (1) is in the off position, the engine oil supply passage is closed, and oil drain passage (14) to the oil pan is opened. This lets the oil drain from beneath control valve (3), and spring (2) pushes control valve (3) to bottom of chamber. This position lets the oil from high pressure oil passage (4) to drain into chamber above the control piston (chamber vents to atmosphere outside of housing). Spring (12) now moves master piston (6) up to its neutral position, away from rocker arm adjustment screw (13). The time necessary for the system to stop operation is approximately 1/10 of a second. The JAKE BRAKE will not be able to operate now until the solenoid is activated again.

Jake Brake Controls

The JAKE BRAKE is activated electrically with three different switches connected in series in the circuit. A manually operated control switch (4) is located on the dash of the vehicle. This is a three position switch that permits an operator a selection of 100%, 50%, or no retardation (braking force).

The next switch in series is clutch switch (3). Clutch switch (3) is set to permit brake operation only when the clutch is engaged. This prevents engine stall by the JAKE BRAKE when the drive line is not engaged with the engine.

The third switch is throttle switch (2), and it permits JAKE BRAKE operation only when throttle is at idle position. Any application of more throttle (fuel increase) will stop current flow and the JAKE BRAKE will not operate.

Clutch switch (3) and throttle switch (2) work automatically after the operator control switch (4) is manually positioned. This control circuit permits any one of the three switches to prevent operation of the brake, but requires all three of the switches to be closed before operation can begin.

A small diode (7) is connected between the load side of switch terminal and ground to protect the switch contacts from arcing.


CONTROL CIRCUIT SCHEMATIC
1. Solenoid. 2. Throttle switch. 3. Clutch switch. 4. Control switch (on dash). 5. Fuse. 6. Battery. 7. Diode.

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