G342 ENGINE Caterpillar


Systems Operation

Usage:

Introduction

NOTE: For Specifications with illustrations, make reference to ENGINE SPECIFICATIONS FOR G342 ENGINE, Form No. REG01526. If the Specifications in Form No. REG01526 are not the same as in the Systems Operation and the Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.

General Information


G342 ENGINE ARRANGEMENT
1. Air cleaner. 2. Aftercooler. 3. Instrument panel. 4. Water pump. 5. Governor. 6. Oil filter. 7. Magneto. 8. Auxiliary water pump. 9. Radiator. 10. Ignition transformer (six). 11. Carburetor. 12. Oil cooler. 13. Power take-off clutch.

The G342 is a inline 6 cylinder engine. The engine has a 5.75 in. (146 mm) bore and a 8 in. (203 mm) stroke.

The engine has a displacement of 1246 cu. in. (20.4 liter). The firing order is 1, 5, 3, 6, 2, 4. The engine weight is approximately 5,250 lbs. (2381 kg).

Ignition System

The ignition system has five basic components: A magneto, ignition transformers for each cylinder, a wiring harness, spark plugs and an instrument panel.

Spark Gap Magneto

The magneto is an alternating current generator that produces the electric source (and stops it at the right time) necessary for spark ignition engines. The basic components of the spark gap magneto are the transformer, rotor, contact breaker, distributor, and condenser.


CROSS SECTION OF SPARK GAP MAGNETO
1. Distributor disc. 2. Cam. 3. Distributor gear and shaft assembly. 4. Brush and spring assembly. 5. Transformer. 6. Distributor block. 7. Contact points. 8. Condenser. 9. Rotor. 10. Impulse coupling.

Transformer (5) has a primary coil made of heavy wire. One end of the primary coil is connected to ground on the transformer core. The other end of the primary coil is connected to contact points (7).

Rotor (9) is a permanent magnet. When the rotor turns, one pole of the magnet in the rotor moves under the core of transformer (5). A flow having the characteristics of the magnet (flux) moves from this pole of the magnet to the opposite pole of the magnet through the layers of the metal core. There is an increase in the flux in the core until the pole is exactly under the core. The flux is then at its largest strength. As the rotor turns more it moves out from under the core and there is a decrease in the flux. The rotor turns so that the opposite pole is under the transformer core. Now the flux must change its direction of flow through the transformer coil. The flux gets larger and then smaller in the opposite direction. The flux direction changes each time the rotor makes a revolution. This flux in the core is all around the wires in the coil of the transformer and causes electricity in the wires.

Cam (2) opens contact points (7) at the point in the alternating current cycle when the voltage in the primary coil is large.

When the points open the circuit is broken and the flux around the primary coil wires suddenly falls (collapses) through the primary coil. This sudden collapse of flux causes the largest voltage (peak voltage) in the primary coil.

At peak voltage the contact on distributor disc (1) is in a position to make a complete circuit through brush and spring assembly (4) in the distributor block and through the low tension leads to the ignition transformers.

Condenser (8) prevents a spark that can cause damage to contact points (7). The electrical energy which normally makes a spark across the gap in the contact points goes into the condenser. When the contact points open wider, the electrical energy in the condenser moves back into the primary coil and adds to the voltage.

When there is an increase of rpm of the rotor, there is an increase in strength of spark at the spark plug electrodes. An impulse coupling (10) is used to cause an increase in rotor rpm as the engine is started. The impulse coupling is not engaged when the engine is in operation.

Solid State Magneto (Fairbanks Morse)

The solid state type magneto makes (generates) current in the alternator section of the magneto. Low tension current is held in the capacitor and then released. Distribution is then made through the distribution board (4). This system has no contact points, contactors, or brushes. There is no spark inside the magneto and only minimum wear. An ignition spark of high tension is made by the transformer to start the air fuel mixture burning under all operating conditions.

The alternator makes a voltage as the magnet rotor is turned by the engine through a drive coupling. The alternating current is sent through a rectifier and held in a capacitor (5). A zener diode, on the power board is the regulator of the capacitor voltage for proper ignition.

As the pulser rotor (8) moves by each pulser coil (trigger circuit) (7), a voltage is made and sent to the electronic switch (silicon controlled rectifier) (9) for the cylinder ready for ignition. The switch is then turned on and permits the capacitor (5) to release the voltage (discharge). Then the voltage goes through the distribution board (4) and to the transformer. The transformer causes a spark (impulse) of high voltage and low current. This is sent across the electrodes of the spark plug. As the pulser rotor moves by each pulser coil, the same development of spark (impulse) is made.


CUTAWAY VIEW OF SOLID STATE MAGNETO (FAIRBANKS MORSE) (Typical Illustration)
1. Timing bolt. 2. Pulser coil assembly. 3. Plate and power board assembly. 4. Distribution board. 5. Capacitor. 6. Alternator housing. 7. Pulser coil (trigger circuit). 8. Pulser rotor. 9. Electronic switch (silicon controlled rectifier). 10. Plug connector.

Solid State Magneto (Altronic)


SOLID STATE MAGNETO (ALTRONIC)
1. Alternator section. 2. Electronic firing section.

The Altronic magneto is made of a permanent magneto alternator section (1) and brakerless electronic firing circuit (2). There are no brushes or distributor contacts.


CROSS SECTION OF SOLID STATE MAGNETO (ALTRONIC)
3. Alternator. 4. Vent. 5. Speed reduction gears. 6. Pick-up coil. 7. Drive tang. 8. Energy storage capacitor. 9. Rotating timer arm. 10. SCR solid state switch. 11. Output connector.

The engine turns magneto drive tang (7). The drive tang turns alternator (3), speed reduction gears (5) and rotating timer arm (9). As the alternator is turned it provides power to charge energy storage capacitor (8). There are separate pick-up coils (6) and SCR (silicon controlled rectifier) solid state switches (10) for each engine cylinder. The timer arm passes over pick-up coils (6) in sequence. The pick-up coils turn on solid state switches (10) which release the energy stored in capacitor (8). This energy leaves the magneto thru output connector (11). The energy travels thru the wiring harness to the ignition coils where it is transformed to the high voltage needed to fire the spark plugs.

Instrument Panel


INSTRUMENT PANEL
1. Stop switch. 2. Gauge for the oil pressure. 3. Reset button for the magnetic switch. 4. Reset button for the gauge for oil pressure. 5. Gauge for the water temperature.

The instrument panel has a magnetic switch, manual stop switch (1), oil pressure gauge (2), and a water temperature gauge (5) which are connected to the magneto. The protection shut-off valve for the gas supply line is also operated by the instrument panel.

When the magnetic switch is activated it connects the magneto to ground and stops the engine. This is the normal way to stop the engine. If the water temperature gets too high or if the oil pressure gets too low the magnetic switch is activated.

Before a cold engine is started, push in reset button (3) for the magnetic switch and reset button (4) for the gauge for the oil pressure. This prevents the connection of the magneto to ground because of low oil pressure. When the engine starts, normal oil pressure releases the switch from reset position. The gauge switch is then ready to stop the engine when the oil pressure is low.

When the gauge switch for the water temperature has correct operation, a hot engine can not be started.

When the reset button for the magnetic switch is held in, the gauge switches for the oil pressure and water temperature can not make connection of the magneto to ground.

The protection shut-off valve for the gas line needs manual setting to open it after the engine has stopped.


OIL PRESSURE GAUGE
4. Reset button for the gauge for oil pressure.

Spark Plugs And Adapters

Spark plugs for this natural gas engine use two ground electrodes. This permits the spark plug to operate longer before adjustment or replacement is needed.


SPARK PLUG AND ADAPTER
1. Cover. 2. High tension wire. 3. Seal. 4. Spark plug adapter. 5. Spark plug.

A cover (1) is used over the spark plug adapter. High tension wire (2) goes through cover (1) to the connection (terminal) portion of spark plug (5). This keeps water, dirt and other foreign material out of spark plug adapter (4).

Ignition Transformer

The ignition transformer causes an increase of the magneto voltage. This is needed to send a spark (impulse) across the electrodes of the spark plugs. For good operation, the connections (terminals) must be clean and tight. The wiring diagram shows how all wires are to be connected to the plug connection at the magneto.


IGNITION TRANSFORMER (Typical Example)

Wiring Diagrams


IGNITION SYSTEM DIAGRAM FOR SPARK GAP MAGNETO
1. Magneto. 2. Spark plugs. 3. Low tension leads. 4. High tension leads. 5. Transformers. 6. Magnetic switch. 7. Manual stop switch. 8. Switch of the gauge for the oil pressure. 9. Switch of the gauge for the water temperature. 10. Instrument panel.


WIRING DIAGRAM WITH OVERSPEED CONTACTOR AND GAS VALVE
1. Solenoid. 2. Gas valve. 3. Overspeed contactor. 4. Shut-off stud for breaker point magneto or H pin for Fairbanks Morse Solid State Magneto or G pin for Altronic Magneto. 5. Magnetic switch. 6. Stop switch. 7. Switch of the gauge for the oil pressure. 8. Switch of the gauge for the water temperature. 9. Engine instrument panel.


IGNITION SYSTEM DIAGRAM FOR SOLID STATE MAGNETO (FAIRBANKS MORSE)


IGNITION SYSTEM DIAGRAM FOR SOLID STATE MAGNETO (ALTRONIC)

Gas, Air Inlet And Exhaust System


GAS, AIR INLET AND EXHAUST SYSTEM (Typical Illustration)
1. Gas pressure regulator. 2. Balance line. 3. Air cleaner. 4. Turbocharger. 5. Carburetor. 6. Gas supply. 7. Governor. 8. Inlet manifold. 9. Cylinder. 10. Aftercooler. 11. Exhaust manifold. 12. Air tube. 13. Differential pressure regulator. 14. Exhaust bypass.

In addition to components shown in the diagram, some installations have a shut-off valve attachment in the supply line for the gas. The valve is electrically operated from the ignition system and can also be manually operated to stop the engine. After the engine is stopped, manual setting is needed to start the engine.

Engine installations using propane gas have system components the same as illustrated above. In addition, on some engines, a Thermac valve for reduction of pressure, and a load adjusting valve, between the gas pressure regulator and carburetor, are used. Later engines with a propane or dual fuel system have a vacuum regulator in place of the gas pressure regulator and Thermac valve. This vacuum regulator permits an adjustment to be made for differences in BTU content of the gas being used.

Changes in engine load and fuel burnt cause changes in rpm of the turbine wheels and impellers of the turbocharger (4).

When the turbocharger gives a pressure boost to the inlet air, the temperature of the air goes up. A water cooled aftercooler (10), is installed between the turbocharger (4) and the air inlet manifold (8) to cylinders. The aftercooler causes a reduction of air temperature from the turbochargers.

Turbocharger (Engines so Equipped)

The turbocharger is on the exhaust outlet of the engine exhaust manifold. The energy that normally would be lost from the exhaust gases is used to turn the turbocharger.

As the engine starts, the flow of exhaust gases from the exhaust manifold goes through inlet (12) to the turbine wheel (6). The turbine wheel and compressor impeller (1) are on a common shaft. The exhaust gases flow over the turbine wheel making it and the impeller turn.

Air from the air cleaner flows through inlet (7) to the center of the impeller. The rotating impeller puts a compression force on the air causing it to go into the carburetor.

The bearings of the turbocharger get pressure lubrication from engine oil. The oil goes in through port (4) and is sent through passages to give lubrication to the thrust bearing (3), sleeves (9 and 11), and the bearings (10).


TURBOCHARGER
1. Compressor impeller. 2. Compressor housing. 3. Thrust bearing. 4. Inlet port for lubrication oil. 5. Turbine housing. 6. Turbine wheel. 7. Air inlet. 8. Exhaust outlet. 9. Sleeve. 10. Shaft journal bearing. 11. Sleeve. 12. Exhaust inlet.

Aftercooler

The aftercooler is installed between the turbocharger and the carburetor. There is a water flow through the aftercooler to cool the hot air which is under compression from the turbocharger. The cool air going through the carburetor makes more oxygen available for combustion. More oxygen permits more fuel to be burned. This gives more power.

Gas Pressure Regulator

The gas pressure regulator is needed on engines equipped with turbochargers. Engines using inlet air that has only the pressure of the atmosphere (naturally aspirated) need a gas pressure regulator if the pressure of the gas supply is more than the desired inlet pressure difference between the gas and air.


GAS PRESSURE REGULATOR
1. Spring side chamber. 2. Adjustment screw. 3. Spring. 4. Outlet. 5. Valve disc. 6. Orifice. 7. Main diaphragm. 8. Lever side chamber. 9. Lever. 10. Pivot pin. 11. Valve stem. 12. Inlet. A. Vent valve.

An adjustment can be made to the regulator by turning screw (2).

Gas goes through inlet (12), orifice (6), by valve disc (5), and through outlet (4). The outlet pressure is in chamber (8) on the lever side of diaphragm (7).

As the gas pressure in the chamber (8) becomes higher than the force of the spring (3) and the air pressure in the spring side chamber (1) (atmosphere on naturally aspirated engines; turbocharger boost on turbocharged engines), the diaphragm is pushed against the spring. This turns the lever (9) a pin (10) and causes the valve stem (11) to move to valve disc (5) to close orifice (6).

When orifice (6) is closed, gas is pulled from chamber (8). This causes a reduction in pressure in chamber (8) to a pressure less than that on the spring side of the diaphragm. The force of the spring and air pressure in the chamber (1) moves the diaphragm toward the lever. This turns the lever and opens the valve disc (5) permitting additional gas to fill chamber (8) and go to the carburetor.

When the pressure on either side of the diaphragm is the same, the regulator permits a set amount of gas flow to the carburetor.

Vent Valve

When the main diaphragm (7) moves toward the spring side of chamber (1), air goes out of chamber. This movement of air pushes the lower flapper (16) up taking upper flapper (13) with it. The air inside chamber (1) is then released. This is done rapidly enough to prevent any loss of time in the main diaphragm because of air compression.


OPERATION OF THE VENT VALVE
13. Upper flapper. 14. Orifice. 15. Orifice plate. 16. Lower flapper. 17. Springs (two).

As the main diaphragm (7) moves toward the lever chamber (8), air moves in to fill the chamber (1). This pushed the upper flapper (13) against the orifice plate (15). Air going through the openings in upper flapper opens the lower flapper (16) and fills chamber (1).

Vacuum Regulator

The vacuum regulator on later engines controls the high BTU gases to a negative pressure (vacuum). Adjustment of the regulator is made by turning the adjustment nut (2).


VACUUM REGULATOR OPERATION
1. Spring side chamber. 2. Adjustment nut. 3. Spring. 4. Outlet. 5. Valve disc. 6. Orifice. 7. Diaphragm. 8. Lever side chamber. 9. Lever. 10. Pin. 11. Valve stem. 12. Inlet.

Gas goes through the inlet (12), orifice (6), by valve disc (5), and through the outlet (4). Vacuum is felt in the chamber (8) on the lever side of diaphragm (7).

When the vacuum in chamber (8) and air pressure in the spring side chamber (1) (atmosphere on naturally aspirated engines; turbocharger boost on turbocharged engines) becomes more than the force of the diaphragm spring (3) the diaphragm is pulled against the force of the spring. This turns (pivots) the lever (9) at pin (10) and causes the valve stem (11) to move the valve disc (5) to open orifice (6).

With the orifice open, gas supply under pressure is sent to the lever side of chamber (8). This causes a loss of vacuum, and permits the spring force to pull the diaphragm and lever to move the valve disc to close the orifice.

When the spring force is balanced by the combination of vacuum and air pressure force, the regulator sends gas to the carburetor at a specific amount.

Balance Line

The balance line controls the correct pressure difference between the line pressure regulator and the carburetor inlet.

When the load on the engine changes, the boost pressure from the turbocharger changes in the inlet manifold. The balance line sends a signal of this change through the vent valve to the spring side chamber of the line pressure regulator. This pressure change causes the regulator diaphragm to move the line regulator valve to correct the gas pressure to the carburetor.

Carburetor

Air goes into the carburetor through air horn (3) and fills outer chamber (4). Air goes into inner chamber (7) (mixing chamber) by moving diaphragm (6) away from ring (14).

Fuel goes into the carburetor through fuel inlet (2), and goes by the power mixture adjustment (5) to the center of the carburetor and into tube (9) for the fuel outlet. Fuel valve (12) is fastened to diaphragm (6). With the diaphragm moved away from ring (14), fuel goes through fuel valve (12) and into chamber (7). The fuel and air mixture in inner chamber (7) goes down by throttle plate (16) and into the inlet manifold.


CARBURETOR OPERATION (Operating Position Shown)
1. Balance line inlet. 2. Fuel inlet. 3. Air horn. 4. Outer chamber. 5. Power mixture adjustment. 6. Diaphragm. 7. Inner chamber. 8. Chamber. 9. Fuel outlet tube. 10. Carburetor body. 11. Spring. 12. Fuel valve. 13. Sensing holes. 14. Ring. 15. Idle adjustment opening. 16. Throttle plate.

With the engine stopped, spring (11) holds diaphragm (6) against ring (14) and holds fuel valve (12) closed. No air or fuel can go to inner chamber (7). As the engine is started, the vacuum in the cylinders, caused by the intake strokes of the pistons, make a low pressure condition in inner chamber (7). This low pressure is felt by chamber (8), behind the diaphragm, through holes (13). This permits the pressure in chamber (8) to balance with the low pressure condition in the inner chamber. As soon as the inlet pressure on the diaphragm (6) is higher than the spring force, the diaphragm moves out.

This also moves fuel valve (12) out and permits air and fuel to go into the inner chamber. A small volume of air is also measured into the inner chamber (7) through idle adjustment opening (15).

When the engine is running at a constant rpm, the diaphragm does not move from one position. This position is caused by the difference in pressure between the gas and the air. An adjustment can be made to this pressure difference by making an adjustment to the gas pressure regulator.

Valves And Valve Mechanism


VALVES AND VALVE MECHANISM
1. Push rod. 2. Rocker arm. 3. Sleeve. 4. Retainer. 5. Outer spring. 6. Inner spring. 7. Valve rotator. 8. Valve bushing (valve guide). 9. Insert. 10. Guide for valve lifter. 11. Valve. 12. Yoke. 13. Valve lifter (cam follower).

The valves and valve mechanism control the flow of air and exhaust gases in the cylinder during engine operation.

The intake and exhaust valves are opened and closed by movement of these components: crankshaft, camshaft, valve lifters (cam followers), push rods, rocker arms, and valve springs. Rotation of the crankshaft causes rotation of the camshaft. The camshaft gear is driven by, and timed to, a gear on the front of the crankshaft. When the camshaft turns, the cams on the camshaft also turn and cause the valve lifters (cam followers) to go up and down. This movement makes the push rods move the rocker arms. The movement of the rocker arms will make the intake and exhaust valves in the cylinder head to open and close according to the firing order of the engine. Two valve springs for each valve help to hold the valves in the closed position.

Valve rotators 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.

Differential Pressure Regulator - (Engines Equipped With Turbocharger)

The differential pressure regulator is installed on the turbine housing (7) of the turbocharger. It controls the amount of exhaust gases to the turbine wheel. The exhaust bypass valve (4) is activated directly by a pressure difference between the air pressure (atmosphere) and the pressure from the turbocharger outlet to the carburetor.

One side of the diaphragm (8) in the regulator feels the pressure of the atmosphere through breather location (5). The other side of the diaphragm feels the air pressure from the outlet side of the turbocharger compressor through a control line at connection (1). When the outlet pressure to the carburetor gets to a valve larger than the force of the pressure on the spring side, the diaphragm moves. This opens valve (4) and the exhaust gases go out the bypass passage (6), not to the turbocharger turbine wheel.


DIFFERENTIAL PRESSURE REGULATOR
1. Regulator control line connection. 2. Spacers. 3. Spring. 4. Bypass valve. 5. Breather location. 6. Bypass passage. 7. Turbine housing. 8. Diaphragm. 9. Shims.

The bypass passage (6) is inside the turbine housing of the turbocharger. Under a constant load on the engine, the valve (4) does not move from one position. This permits just enough gas to go to the turbine wheel, turning it and giving the correct air pressure to the carburetor.

Mechanical Governor

The governor is in the housing for the accessory drive and governor. The governor control is connected to the control lever on the engine governor. The governor controls the amount of fuel needed to keep the engine at the desired rpm.

The governor has weights (7) which are on a shaft driven by the engine. Force of rotation (centrifugal force) of the weights on the retainer (2), bearing (6) and lever (5) puts a force against the force of governor spring assembly (1). These two forces move the lever (5) which is connected to the linkage to the carburetor.


MECHANICAL GOVERNOR
1. Governor spring assembly. 2. Retainer. 3. Bearing. 4. Cover. 5. Lever assembly. 6. Bearing. 7. Governor weights. 8. Tube for oil.

The governor control controls only the tension of the governor spring assembly (1). Tension of the spring always pulls to give more fuel to the engine. The force of rotation (centrifugal force) of the governor weights is always pushing to get a reduction of fuel to the engine. When these two forces are in balance the engine runs at desired rpm (governed rpm).

When there is an increase in the load on the engine, there is a reduction in the rpm of the engine. The rotation of the governor weights (7) gets slower (the governor weights move toward each other) and the force on the lever (5) is less. The governor spring assembly (1) moves the linkage to the carburetor to give more fuel to the engine. The engine rpm goes up until the force of rotation of the governor weights is fast enough to be in balance with the force of the governor spring assembly.

When there is a decrease in the engine load there will be an increase in the rpm of the engine and the rotation of the governor weights (7) will get faster. This moves the retainer (2), bearing (6) and lever (5) and puts more force against the governor spring assembly. This causes a reduction in the amount of fuel to the engine. Engine rpm goes down until the force of rotation (centrifugal force) of the governor weights is in balance with the force of the governor spring assembly. When these two forces are in balance the engine will run at the desired rpm (governed rpm).

Oil from the engine gives lubrication to the governor. Oil from the bearing assembly for the accessory shaft goes to cover (4) through tube (9). A passage in the cover gives oil to bearing (3). The governor shaft has oil holes in it to give lubrication to the bearing in retainer (3). The other parts of the governor get lubrication from oil thrown by parts (splash lubrication). Oil from the governor goes into the housing for the timing gear through an oil return hole in the front of the housing for the governor and magneto drive.

Timing Gears

The timing gears are at the front of the cylinder block. Their cover is the housing for the timing gears. The timing gears keep the rotation of the crankshaft, camshaft, and magneto and governor drive in the correct relation to each other. The timing gears are driven by the gear on the crankshaft.

The gear (6) on the crankshaft drives the large outer gear on the camshaft. This gear drives the idler gear (3) which drives the gear (4) for the water pump. The small inner gear (5) on the camshaft drives gear (1) for the governor and magneto drive. The gear (6) on the crankshaft also drives the idler gear (7) which drives gear (8) for the oil pump drive.


TIMING GEARS
1. Gear for the governor and magneto drive. 2. Large outer gear on the camshaft. 3. Idler gear for the water pump. 4. Gear for the water pump. 5. Small inner gear on the camshaft. 6. Gear on the crankshaft. 7. Idler gear for the oil pump drive. 8. Gear for the oil pump drive.

NOTE: Timing mark "A" on gear (6) is not for the G342 Engine.

Lubrication System


LUBRICATION SYSTEM
1. Oil supply line for turbocharger. 2. Rocker arm shaft. 3. Oil tube from oil manifold to rear rocker arm shaft (similar tube to front rocker arm shaft). 4. Tube for oil pressure gauge. 5. Oil return line from turbocharger. 6. Oil filters (two). 7. Oil filter base. 8. Oil manifold. 9. Tube. 10. Passage to main bearing. 11. Tube from oil cooler. 12. Tube to oil cooler. 13. Tube from oil filter base to magneto drive. 14. Passage in connecting rod. 15. Rear scavenger suction bell. 16. Passage in crankshaft. 17. Passage from oil pump to oil filter base. 18. Oil pump (three section). 19. Oil pump drive shaft. 20. Front scavenger suction bell.

Flow Of Oil Through The Engine (Normal Operation)

The lubrication system uses a three section oil pump (18). The oil pump is in the oil pan and is driven by drive shaft (19) from the engine gears. Oil returns to the center of the oil pan through suction bells (15 and 20).

Oil is sent from the oil pan by the oil pump (18) through passage (17) to oil filter base (7). Oil from the oil filter base goes through tube (12) to the oil cooler, (on the left side of the engine). Oil goes through the oil cooler from front to rear and returns to the filter base through tube (11). From the oil filter base the oil goes through the oil filters (6) and to the oil manifold (8).

A turbocharger lubrication valve, oil cooler bypass valve, and oil filter bypass valve are in the oil filter base. See the subject, FLOW OF OIL THROUGH THE OIL COOLER AND OIL FILTERS.

Oil is sent from the oil manifold through tube (9) and passages (10) to each main bearing for the crankshaft.

Passages (16) send oil from the main bearings to the bearings for the connecting rods. Passages (14) in the connecting rods give lubrication for the piston pins and for the cooling of the piston.

A tube from the oil manifold gives oil to the timing gears. See the subject, LUBRICATION FOR THE TIMING GEARS.

Inside passages and tubes (3) send oil from the oil manifold to rocker arm shaft (2). This oil gives lubrication to the rocker arms, valve bushings (guides), push rods, and valve lifters (cam followers). Tube (13) sends oil to the magneto drive. Tube (4) sends oil to the gauge for the oil pressure.

The bearings for the camshaft get oil by splash lubrication (oil thrown by other parts).

After the oil has given lubrication to the engine, it returns to the engine oil pan.

Flow Of Oil Through The Oil Cooler And Oil Filters

Oil filter bypass valve (7), oil cooler bypass valve (8), and turbocharger lubrication valve (3) are in the oil filter base.

When the oil is cold (when the engine is first started), the bypass valve for the oil cooler will open. Oil from the oil pump is sent through the opened bypass valve for the oil cooler to the oil filters (1). Oil goes through the oil filters and on to passage (6) to the oil manifold to give lubrication to the engine.


FLOW OF OIL (COLD OIL)
1. Oil filters (two). 2. Oil supply line for turbocharger. 3. Turbocharger lubrication valve. 4. Oil filter base. 5. Oil cooler. 6. Passage to oil manifold. 7. Oil filter bypass valve. 8. Oil cooler bypass valve.

As the temperature of the oil goes up, the bypass valve for the oil cooler will close and the oil will go through oil cooler (5) and then to the oil filters.

When the engine is started, the lubrication valve for the turbocharger will be open. The oil from the oil pump goes through line (2) to the turbocharger.

As the pressure of the oil through the oil filters goes up, the lubrication valve for the turbocharger will close and the oil will go through the oil filters and then to the turbocharger.


FLOW OF OIL (NORMAL OPERATION)
1. Oil filters (two). 2. Oil supply line for turbocharger. 3. Turbocharger lubrication valve. 4. Oil filter base. 5. Oil cooler. 6. Passage to oil manifold. 7. Oil filter bypass valve. 8. Oil cooler bypass valve.

The bypass valve for the oil filters will open if the oil filters have a restriction. This allows the oil to go from the oil pump directly to passage (6). Only clean oil goes to the engine, unless the filters have a restriction or the viscosity of the oil is too high.

The bypass valves (7 and 8) makes it possible for the engine to have lubrication if the oil filters, oil cooler, or both the oil filters and oil cooler have a restriction.

Lubrication For The Timing Gears

Oil under pressure comes from the oil manifold through tube (12) to passage (14), to the front bearing for the crankshaft (13), and to fitting (11).

Oil goes through tubes (9 and 2) to passages (8 and 1) in the cylinder block and gives lubrication to the bearing for the governor shaft (6), the governor, and the front bearing for the camshaft (10). Part of the oil goes through tube (3) and passage (4) to give lubrication to the bearing for water pump idler shaft (7). Tube (5) sends oil to the drive gear for the water pump.


TIMING GEAR LUBRICATION
1. Oil passage to bearing for governor drive shaft. 2. Oil tube to bearing for camshaft. 3. Oil tube to passage (4). 4. Oil passage to bearing for water pump idler shaft. 5. Oil tube to water pump gear. 6. Bearing for governor drive shaft. 7. Bearing for water pump idler shaft. 8. Passage in block. 9. Tube from oil passage in front of block. 10. Front bearing for camshaft. 11. Fitting. 12. Supply tube from oil manifold. 13. Front bearing for crankshaft. 14. Passage to front bearing for crankshaft.

Cooling System

Radiator Cooled System


FLOW OF COOLANT IN RADIATOR COOLING SYSTEM
1. Cylinder head. 2. Aftercooler. 3. Water manifold. 4. Lines to and from aftercooler. 5. Radiator inlet line. 6. Radiator cap. 7. Radiator. 8. Auxiliary water pump. 9. Temperature regulators. 10. Bypass line. 11. Cylinder block. 12. Oil cooler. 13. Water pump. 14. Radiator outlet line.

Water pump (13) is gear driven by the engine timing gears. The water pump gets coolant from the bottom tank of radiator (7) and sends some of the coolant into cylinder block (11). The remainder of the coolant goes through oil cooler (12), to cool the oil for lubrication of the engine, and into the cylinder block.

The coolant then goes around the cylinder block, around the cylinder liners and up through the water ferrules and directors into cylinder head (1).

Coolant moves through the cylinder head and into water manifold (3). The coolant goes through the water manifold to temperature regulators (9) at the front of the water manifold. If the coolant is cold (cool), the temperature regulators will be closed. The coolant will go through bypass line (10) to the water pump. If the coolant is warm, the temperature regulators will be open and the coolant will go through line (5) and into the top tank of the radiator. Coolant then goes through the core of the radiator to the bottom tank, where it is again sent through the cooling system. A small part of the coolant goes through bypass line (10) when the temperature regulators are open.

Radiator cap (6) is used to keep the correct pressure in the cooling system. This pressure keeps a constant supply of coolant to the water pump. If this pressure goes too high, a valve in the radiator cap moves (opens) to get a reduction of pressure. When the correct pressure is in the cooling system, the valve in the radiator cap moves down (to the closed position).

If the engine is equipped with a turbocharger and aftercooler, the auxiliary water pump (8) takes water from an outside source and sends it through lines (4) to the aftercooler (2).

Heat Exchanger Cooled System


FLOW OF COOLANT IN HEAT EXCHANGER COOLED SYSTEM
1. Cylinder head. 2. Aftercooler. 3. Water manifold. 4. Coolant outlet line. 5. Expansion tank. 6. Heat exchanger. 7. Outlet line for sea water. 8. Temperature regulators. 9. Auxiliary water pump. 10. Cylinder block. 11. Oil cooler. 12. Water pump. 13. Bypass line. 14. Lines to and from aftercooler.

Water pump (12) is gear driven by the engine timing gears. The water pump gets coolant from expansion tank (5) and sends some of the coolant into cylinder block (10). The remainder of the coolant goes through oil cooler (11), to cool the oil for lubrication of the engine, and then into the cylinder block.

The coolant then goes around the cylinder block, around the cylinder liners and up through the water ferrules and directors into cylinder head (1).

Coolant moves through the cylinder head and into water manifold (3). The coolant goes through the water manifold to temperature regulators (8) at the front of the water manifold. If the coolant is cold (cool), the temperature regulators will be closed. The coolant will go through bypass line (13) to the water pump. If the coolant is warm, the temperature regulators will be open and the coolant will go through line (4) and into heat exchanger (6). The coolant goes through the heat exchanger where it is cooled. The coolant goes from the heat exchanger to expansion tank (5) where it is again sent through the cooling system. A small part of the coolant goes through bypass line (13) when the temperature regulators are open.

Auxiliary water pump (9) sends water to heat exchanger (6). This water cools the coolant for the engine by going around the coils in the heat exchanger and then out through line (7). The auxiliary water pump also sends water to the aftercooler (2) through lines (14).

Basic Block

Cylinder Block, Liners And Heads

Earlier engines did not have spacer plates. The block was counterbored for the cylinder liner flange.

On later engines a steel spacer plate is used between the cylinder head and the block to eliminate liner counterbore and to provide maximum liner flange support area (the liner flange sits directly on the cylinder block).

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

The engine has two cylinder heads. Two vertical valves (one intake and one exhaust), controlled by a push rod valve system, are used for each cylinder. Each valve has a rotator to extend valve life. Replaceable valve guides are pressed into the cylinder head.

Camshaft

The engine has a single camshaft that is driven at the front end. It is supported by four bearings. As the camshaft turns, each cam (lobe) (through the action of valve systems components) moves either the exhaust valve or the intake valve for each cylinder. The camshaft gear must be timed to the crankshaft gear. The relation of the cams (lobes) to the camshaft gear cause the valves in each cylinder to open and close at the correct time.

Crankshaft

The crankshaft changes the combustion forces in the cylinder into usable rotating torque which powers the machine. Vibration, caused by combustion impacts along the crankshaft, is kept small by a vibration damper on the front of the crankshaft.

There is a gear at the front of the crankshaft to drive the timing gears which drive the camshaft, oil pump, water pump and governor. Pressure oil is supplied to all bearing surfaces through drilled holes in the crankshaft. The crankshaft is supported by seven main bearings. The center main bearing controls the end play of the crankshaft.

Pistons

The cast aluminum piston has four rings. The top ring or compression ring is seated in an iron band that is cast into the piston. The center two rings or intermediate rings seat directly in grooves machined in the piston. The lower ring is the oil ring. Holes in the oil ring groove return oil removed from the cylinder walls to crankcase. All four rings are above the piston pin bore.

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

Vibration Damper

Viscous Type Damper

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 weight (1) in a metal case (3). The small space (2) between the case and weight is filled with a thick fluid. The fluid permits the weight to move in the case to cause a reduction of vibrations of the crankshaft.


CROSS SECTION OF A TYPICAL VIBRATION DAMPER
1. Solid cast iron weight. 2. Space between weight and case. 3. Case.

Rubber Ring Type Damper

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.


CROSS SECTION OF A VIBRATION DAMPER
1. Flywheel ring. 2. Rubber ring. 3. Inner hub. 4. Bolt.

Electrical System

The electrical system has 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), disconnect switch, 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 or a generator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output to keep the battery at full charge.


NOTICE

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


If the engine has a disconnect switch, the starting circuit can operate only after the disconnect switch is put in the ON position.

The starting circuit is in operation only when the start switch is activated.

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 (Delco-Remy)

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 fingers 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.


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

Alternator (Motorola)

The alternator is a three phase, self-rectifying charging unit that is driven by V-type belts. The only part of the alternator that has movement is the rotor assembly. Rotor assembly (4) is held in position by a ball bearing at each end of the rotor shaft.

The alternator is made up of a front frame at the drive end, rotor assembly (4), stator assembly (3), rectifier assembly, brushes and holder assembly (5), slip rings (1) and rear end frame. Fan (2) provides heat removal by the movement of air thru the alternator.

Rotor assembly (4) has field windings (wires around an iron core) that make magnetic lines of force when direct current (DC) flows thru them. As the rotor assembly turns, the magnetic lines of force are broken by stator assembly (3). This makes alternator current (AC) in the stator. The rectifier assembly has diodes that change the alternating current (AC) from the stator to direct current (DC). Most of the DC current goes to charge the battery and make a supply for the low amperage circuit. The remainder of the DC current is sent to the field windings thru the brushes.


ALTERNATOR
1. Slip rings. 2. Fan. 3. Stator assembly. 4. Rotor assembly. 5. Brush and holder assembly.

Voltage Regulator (Motorola)

The voltage regulator is not fastened to the alternator, but is mounted separately and is connected to the alternator with wires. The 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. There is a voltage adjustment for this regulator to change the alternator output.


ALTERNATOR REGULATOR (MOTOROLA)
1. Cap for adjustment screw.

Generator


CUTAWAY VIEW OF A GENERATOR
1. Brush assembly. 2. Field. 3. Commutator. 4. Armature.

The generator is turned by a gear system from the drive gear for the water pump. The generator keeps charge in the battery and gives a supply of current to operate the electrical components.

Generator Regulator

The generator regulator controls the output of the generator. The regulator has three controls: the cutout relay (1), the voltage regulator (3) and the current regulator (2). Each control has contact points which are operated by electrically activated magnets (electromagnets).

Springs hold the cutout relay points open and the voltage regulator and current regulator contact points closed. The spring tension for each unit is a force in the opposite direction of the force of the electromagnets.


GENERATOR REGULATOR
1. Cutout relay. 2. Current regulator. 3. Voltage regulator. 4. Battery terminal. 5. Generator terminal. 6. Field terminal.

The cutout relay prevents the battery from making a motor of a generator that is not making enough voltage. Generator voltage that is approximately equal to battery voltage will close the cutout relay points. This closes the circuit between the generator and the battery. The generator can now give a supply of electricity to the battery and components of the electrical system.

The voltage regulator prevents the generator from making high voltage that would cause damage to the electrical components. Generator voltage that is a small amount more than the battery voltage opens the regulator points causing the generator output to be less. Low generator voltage permits the spring to close the regulator points and the generator voltage is high again. This action of the voltage regulator points, opening and closing, controls the output voltage of the generator. The points can open and close as often as 200 times per second.

The current regulator (2) prevents too much current from being made by the generator so the generator will constantly be making voltage the same as the battery voltage. When the generator makes current the same as the current regulator setting, the regulator contact points open. These open points cause the generator current to be lower. The low current permits the spring to close the points and the generator current is high again. The opening and closing of the current regulator points causes limited current from the generator. The points can open and close as often as 200 times per second.

When the loads on the generator are low and the battery needs very little charge, the voltage regulator contact points (3) are operating. When the electric loads are high, current regulator contact points are operating. The contact points of the two units will never open at the same time.


SCHEMATIC OF WIRING DIAGRAM OF GENERATOR REGULATOR
1. Cutout relay. 2. Current regulator. 3. Voltage regulator. 4. Battery terminal. 5. Generator terminal. 6. Field terminal. 7. Battery. 8. Generator. 9. Ammeter. 10. Field connection. 11. Armature connection.

Starting System Components

Starter Motor

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


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

The starter motor has a solenoid. When the start switch is activated, electricity from the electrical system will cause the solenoid to move the starter pinion 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 starter motor. When the start which is released, the starter pinion will move away from the ring gear of the flywheel.

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.


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

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.

Wiring Diagrams

There are many wiring diagrams for these engines. The diagrams are together by the type of electrical system. The diagrams for the charging systems are together by the alternator type.

These engines can have electric, air, or hydraulic starting and charging systems. These engines can also have combinations of these systems. Be sure that the diagram is correct for the engine.

Negative Ground Systems

These systems are used in applications when it is not necessary to prevent radio distortion and/or chemical changes (electrolysis) of grounded components.


NEGATIVE GROUND 24V, 15 AMP, SYSTEM (DELCO REMY GENERATOR)
1. Start button. 2. Lights, alarm and other loads. 3. Starting motor. 4. Ammeter. 5. Battery terminal. 6. Generator terminal. 7. Field terminal. 8. Generator regulator. 9. Battery. 10. Generator.


NEGATIVE GROUND 24V, 15 AMP, SYSTEM FOR USE WITH AIR OR HYDRAULIC STARTING (DELCO REMY GENERATOR)
1. Start button. 2. Lights, alarm and other loads. 3. Ammeter. 4. Battery terminal. 5. Generator terminal. 6. Field terminal. 7. Generator regulator. 8. Control relay for air motor. 9. Battery. 10. Generator.

Insulated Systems

These systems are most often used in applications where radio interference is not desired or where conditions are such that grounded components will have corrosion from chemical change (electrolysis).


INSULATED 24V, 15 AMP, SYSTEM (DELCO REMY GENERATOR)
1. Start button. 2. Ammeter. 3. Lights, alarm and other loads. 4. Starter motor. 5. Battery terminal. 6. Generator terminal. 7. Field terminal. 8. Generator regulator. 9. Battery. 10. Generator.


INSULATED 24V, 15 AMP, SYSTEM FOR USE WITH AIR OR HYDRAULIC STARTING (DELCO REMY GENERATOR)
1. Start button. 2. Ammeter. 3. Lights, alarm and other loads. 4. Battery terminal. 5. Generator terminal. 6. Field terminal. 7. Generator terminal. 8. Control relay for air motor. 9. Battery. 10. Generator.

(Motorola Alternator)


CHARGING SYSTEM
1. Ammeter. 2. Regulator. 3. Pressure switch (N.O.). 4. Resistor (installed only on 30 and 32 volt systems. On 12 and 24 volt systems, the alternator and regulator are connected without the resistor). 5. Battery. 6. Alternator.


CHARGING SYSTEM WITH ELECTRIC STARTER MOTOR
1. Start switch. 2. Ammeter. 3. Regulator. 4. Starter motor. 5. Pressure switch (N.O.). 6. Resistor (installed only on 30 and 32 volt systems. On 12 and 24 volt systems, the alternator and regulator are connected without the resistor). 7. Battery. 8. Alternator.

(Delco-Remy Alternator) (Regulator Inside Alternator)


CHARGING SYSTEM
1. Ammeter. 2. Alternator. 3. Battery.


CHARGING SYSTEM WITH ELECTRIC STARTER MOTOR
1. Start switch. 2. Ammeter. 3. Alternator. 4. Battery. 5. Starter motor.

Air Starting System

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


AIR STARTING SYSTEM (Typical Example)
1. Starter control valve. 2. Oiler. 3. Relay valve. 4. Air starting motor.

The air starting motor is on the right side of the engine. Normally the air for the starting motor is from a storage tank which is filled by an air compressor installed on the left front of the engine. The air storage tank holds 10.5 cu. ft. (297 liter) of air at 250 psi (1720 kPa) when filled.

For engines which do not have heavy loads when starting, the regulator setting is approximately 100 psi (690 kPa). This setting gives a good relationship between cranking speeds fast enough for easy starting and the length of time the air starting motor can turn the engine before the air supply is gone.

If the engine has a heavy load which can not be disconnected during starting, the setting of the air pressure regulating valve needs to be higher in order to get high enough speed for easy starting.

The air consumption is directly related to speed, the air pressure is related to the effort necessary to turn the engine flywheel. The setting of the air pressure regulator can be up to 150 psi (1030 kPa) if necessary to get the correct cranking speed for a heavily loaded engine. With the correct setting, the air starting motor can turn the heavily loaded engine as fast and as long as it can turn a lightly loaded engine.

Other air supplies can be used if they have the correct pressure and volume. For good life of the air starting motor, the supply should be free of dirt and water. The maximum pressure for use in the air starting motor is 150 psi (1030 kPa). Higher pressures can cause safety problems. The 1L5011 Regulating and Pressure Reducing Valve Group has the correct characteristics for use with the air starting motor. Most other types of regulators do not have the correct characteristics. Do not use a different style of valve in its place.


AIR STARTING MOTOR
5. Air inlet. 6. Rotor. 7. Vanes. 8. Pinion. 9. Gears. 10. Piston. 11. Pinion spring.

The air from the supply goes to relay valve (3). The starter control valve (1) is connected to the line before the relay valve (3). The flow of air is stopped by the relay valve (3) until the starter control valve (1) is activated. Then air from the starter control valve (1) goes to the piston (10) behind the pinion (8) for the starter. The air pressure on the piston (10) puts the spring (11) in compression and puts the pinion (8) in engagement with the flywheel gear. When the pinion is in engagement, air can go out through another line to the relay valve (3). The air activates the relay valve (3) which opens the supply line to the air starting motor.

The flow of air goes through the oiler (2) where it picks up lubrication oil for the air starting motor.

The air with lubrication oil goes into the air motor. The pressure of the air pushes against the vanes (7) in the rotor (6). This turns the rotor which is connected by gears (9) to the starter pinion (8) which turns the engine flywheel.

When the engine starts running the flywheel will start to turn faster than the starter pinion (8). The pinion (8) retracts under this condition. This prevents damage to the motor, pinion (8) or flywheel gear.

When the starter control valve (1) is released, the air pressure and flow to the piston (10) behind the starter pinion (8) is stopped, the pinion spring (11) retracts the pinion (8). The relay valve (3) stops the flow of air to the air starting motor.

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