FUEL SYSTEM SCHEMATIC
1. Fuel return to fuel tank or standpipe (if so equipped). 2. Fuel filter bypass valve. 3. Fuel filter. 4. Fuel injection pump. 5. Precombustion chamber. 6. Fuel supply line. 7. Primary fuel filter. 8. Fuel transfer pump. 9. Fuel transfer pump bypass valve. 10. Fuel injection pump housing fuel manifold.
The fuel system is a pressure type with a separate injection pump and injection valve for each cylinder. Fuel is injected into a precombustion chamber, not directly into the cylinder.
A transfer pump supplies fuel to the manifold from which the injection pumps get fuel. Before the fuel is delivered to the manifold, it may be filtered first by a primary filter attachment which removes dirt particles, and is filtered by a final filter which removes more minute particles.
The transfer pump can supply more fuel than is required for injection, so a bypass valve is used to limit the maximum pressure within the supply system.
The injection pumps receive fuel from the manifold and force it under high pressure to the injection valves. The injection valves spray atomized fuel into the precombustion chambers.
An air vent valve in the system permits removal of air. Air is removed by opening the valve and pressurizing the fuel system. The system can be pressurized by using the priming pump. The vent valve must be open until a stream of fuel, without air bubbles, flows from the vent line.
Fuel Injection Pump Operation
FUEL INJECTION PUMP HOUSING AND PUMP CROSS SECTION
1. Fuel manifold. 2. Inlet port. 3. Check valve. 4. Gear segment. 5. Pump plunger. 6. Spring. 7. Fuel rack. 8. Lifter. 9. Camshaft.
The injection pump plungers and the lifters are lifted by lobes on the camshaft and always make a full stroke. The lifters are held against the cam lobes by springs.
The amount of fuel pumped each stroke is varied by turning the plunger in the barrel. Action of the governor moves the fuel rack which turns the pump gear segment on the bottom of the pump plunger.
The governor control is linked to the lever on the engine governor. The operation of the governor controls the amount of fuel necessary for the engine to maintain the selected engine rpm even when the load changes.
The hydra-mechanical governor has engine driven governor weights (12), governor spring (5), a hydraulic valve (13) and piston (14). The valve and piston are connected to rack (17) in the fuel injection pump housing. The engine lubricating oil pump supplies pressure oil through passage (16) and around sleeve (15) for the hydraulic operation of the governor. The accelerator pedal controls only the compression of governor spring (5). The compressed spring force always pushes to increase the supply of fuel to the engine while the centrifugal force of the engine driven governor weights are always pulling to decrease fuel to the engine. The governed rpm of the engine is when these two forces balance.
HYDRA-MECHANICAL GOVERNOR (Typical Example)
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. Weights. 13. Valve. 14. Piston. 15. Sleeve. 16. Oil passage. 17. Fuel rack. The governor valve is shown in the position when the force of the weights and the force of the spring are balanced.
When engine load increases, engine rpm decreases and revolving weights (12) slow down. The weights move toward each other and allow governor spring (5) to move valve (13) forward. As valve (13) moves, an oil passage around valve (13) opens to pressure oil. Oil then flows through passage (7) and fills the chamber behind piston (14). The pressure forces the piston and rack forward, increasing the amount of fuel to the engine. Engine rpm increases until the revolving weights rotate fast enough to balance the force of the governor spring.
When engine load decreases, engine rpm increases, revolving weights (12) speed-up, and the toes on the weights move valve (13) rearward, allowing the oil behind piston (14) to flow through a drain passage opened at the rear of the piston. At the same time, the pressure oil between sleeve (15) and piston (14) forces the piston and rack rearward, decreasing the amount of fuel to the engine. Engine rpm decreases until the revolving weights balance the force of the governor spring.
When the engine is started, speed limiter plunger (2) restricts the movement of the governor control linkage. When operating oil pressure is reached, the plunger in the speed limiter retracts and the governor control can be moved to the HIGH IDLE position.
When the engine rpm is at LOW IDLE, a spring-loaded plunger within the lever assembly in the governor bears against the shoulder of the low idle adjusting screw. To stop the engine, the plunger must be forced past the shoulder on the adjusting screw.
Oil from the engine lubricating system lubricates the governor weight bearing. The various other parts are splash lubricated. The oil from the governor drains into the fuel injection pump housing.
Fuel Ratio Control
Fuel ratio control bolt (7) is connected by a slot in collar (3) and bolt (4) through the engine governor to the fuel injection pump rack. An air line from the engine inlet manifold supplies manifold pressure air to the chamber inside cover (5).
When the engine is accelerated, or the load on the engine increases, bolt (7) in collar (3) restricts the movement of the fuel rack until the turbocharged boost of air in the inlet manifold and inside the fuel ratio control cover (5) forces diaphragm (2) to compress spring (6). Compressing spring (6) moves bolt (7) which relieves the restriction from collar (3) and the fuel rack. This allows the fuel rack to increase the fuel as the turbocharged air pressure increases with the increase in engine rpm. The compressed force of spring (1) can be adjusted if it is necessary to correct the fuel-to-air ratio.
FUEL RATIO CONTROL-CROSS SECTION
1. Spring. 2. Diaphragm. 3. Collar. 4. Bolt. 5. Cover. 6. Spring. 7. Bolt.
Fuel Injection Valve
FUEL INJECTION VALVE IN PRECOMBUSTION CHAMBER
1. Fuel line assembly. 2. Seal. 3. Body. 4. Nut. 5. Seal. 6. Nozzle assembly. 7. Glow plug. 8. Precombustion chamber.
Fuel, under high pressure from the injection pumps, is transferred through the injection lines to the injection valves. As high pressure fuel enters the nozzle assembly, the check valve within the nozzle opens and permits the fuel to enter the precombustion chamber. The injection valve provides the proper spray pattern.
LUBRICATION SYSTEM COMPONENTS (D333C Illustrated)
The arrows show the approximate direction of oil flow in the engine. 1. Oil filter base (includes bypass valves). 2. Engine oil cooler. 3. Turbocharger oil reservoir in center section. 4. Oil passage through rocker arm shaft. 5. Oil cooler bypass valve. 6. Timing gears (in front compartment). 7. Oil pump (in front part of oil pan). 8. Oil filter case. 9. Oil pan (sump). 10. Oil filter bypass valve. 11. Oil manifold (in cylinder block assembly).
The lubrication system consists of a sump (oil pan), oil pump, oil cooler and oil filter. The cylinder block contains an oil manifold and oil passages to direct the oil to the various parts.
The pump draws oil from the sump and forces the oil through the oil cooler, oil filter, and into the oil manifold. Oil flows through connecting passages to the external and internal engine parts. A regulating valve in the pump body controls the maximum pressure of the oil from the pump.
When the engine is started, the lubricating oil in the oil pan is cold (cool). This cool viscous oil does not flow readily through the system. This cool oil forces bypass valves, in the oil cooler to open, and allows an unrestricted oil flow through the engine.
As the temperature of the oil increases, the viscosity and pressure of the oil decreases, and the bypass valves close. Now, only filtered oil is delivered to the engine parts.
A dirty or clogged oil filter element will not prevent lubricating oil from being delivered to the engine parts. The oil filter bypass valve will open, allowing oil to bypass the element.
The oil manifold directs lubricant to the main bearing supply passages, timing gear bearings, to a passage leading through the cylinder head to the valve rocker arm shaft, and the rocker arms and valves.
Oil spray orifices in the engine block, near the crankshaft main bearings, spray oil on the underside of the pistons. This cools the pistons and provides lubricant for the piston pins, cylinder walls and piston rings.
The connecting rod bearings receive oil through drilled passages in the crankshaft, between the main bearing journals and connecting rod journals.
Oil draining from the valve rocker arms lubricates the valves, push rods and lifters. On six cylinder engines, the camshaft cams, and the camshaft intermediate and rear bearings, are splash lubricated. On four cylinder engines, the camshaft cams are splash lubricated and the camshaft bearings are pressure lubricated.
All timing gear bearings, except the accessory drive gear bearing, are pressure lubricated. Oil is supplied to the bearings through passages in the cylinder block. The accessory drive gear bearing is lubricated by oil draining from the accessory drive shaft housing.
When the engine is warm, and running at rated speed, the oil pressure gauge should register in the "operating range." A lower pressure reading is normal at idling speeds.
A small orifice in the gauge connection prevents rapid gauge fluctuation. Check this orifice for dirt if the gauge becomes inoperative.
RADIATOR COOLING SYSTEM FLOW DIAGRAM
1. Radiator. 2. Coolant external bypass line (D330C and D333C); elbow with internal bypass for coolant (3304 and 3306). 3. Temperature regulator housing or elbow. 4. Cylinder head. 5. Engine oil cooler. 6. Radiator outlet line. 7. Water pump. 8. Cylinder block.
HEAT EXCHANGER COOLING SYSTEM FLOW DIAGRAM
1. Heat exchanger. 2. Coolant external bypass line (D330C and D333C); elbow with internal bypass for coolant (3304 and 3306). 3. Temperature regulator housing or elbow. 4. Fresh water cooled exhaust manifold shield. 5. Cylinder head. 6. Heat exchanger outlet pipe. 7. Cylinder block. 8. Oil cooler bonnet (flow divided to exhaust manifold shield, marine gear oil cooler, if so equipped, and cylinder block). 9. Fresh water pump. 10. Marine gear oil cooler (D330C and D333C). 11. Engine oil cooler. 12. Raw water pump to heat exchanger core line. 13. Raw water discharge overboard line. 14. Raw water pump. 15. Raw water supply line.
KEEL COOLING SYSTEM FLOW DIAGRAM
1. Expansion tank. 2. Coolant external bypass line (D330C and D333C); elbow with internal bypass for coolant (3304 and 3306). 3. Temperature regulator housing or elbow. 4. Water cooled exhaust manifold shield. 5. Cylinder head. 6. Expansion tank outlet line. 7. Cylinder block. 8. Oil cooler bonnet (flow divided to exhaust manifold shield, marine gear oil cooler, if so equipped, and cylinder block). 9. Water pump. 10. Marine gear oil cooler (D330C and D333C). 11. Engine oil cooler. 12. Keel cooling coil.
The electrical system is a combination of three separate electric circuits: the charging circuit, the starting circuit and the lighting or load circuit. Each circuit is dependent on some of the same components. The battery (batteries), ammeter, cables and wires from the battery are common in each of the three circuits.
The charging circuit is in operation when the diesel engine is operating. The electricity producing (charging) unit is a generator or alternator. A regulator in the circuit senses the state of charge in the battery and regulates the charging unit output to keep the battery fully charged.
The starting circuit operates only when the start switch is actuated.
The direct electric diesel engine starting circuit may include a glow plug for each diesel engine cylinder. The glow plugs are small heating elements in the precombustion chambers which promote fuel ignition when the engine is started in low temperatures.
The low amperage load and charging circuits are both connected on the same side of the ammeter while the starting circuit connects to the other side of the ammeter.
Never operate the alternator without the battery in the circuit. Making or breaking an alternator connection with heavy load on the circuit will sometimes result in regulator damage.
This alternator is a three phase self-rectifying charging unit.
The alternator has four main components: end frame assembly (brush end), rotor assembly, stator and shell assembly, and end frame assembly (drive end).
A separate regulator senses the charge condition of the battery as well as electrical system power demand and controls the alternator output accordingly by limiting the field current.
1. Hollow head screw. 2. Connector.
ALTERNATOR CHARGING CIRCUIT-SCHEMATIC (Negative Ground System Illustrated)
The alternator is belt driven from the crankshaft pulley. It is a three-phase self-rectifying charging unit with three main functional parts: A rotating magnetic field (rotor) which produces flux; a stationary armature (stator) in which alternating current is induced; and stationary rectifying diodes that change alternating current to direct current.
The alternator field current is passed through brushes. The field current is in the order of 2 to 3 amperes. The rectifying diodes will pass current from the alternator to the battery or load, but will not pass current from the battery to the alternator.
The separate transistorized voltage regulator is an electronic switching device. It senses the voltage in the system at the oil pressure switch and supplies the necessary field current to maintain the required system voltage. The voltage regulator has two basic "circuits." The "load circuit" conducts positive potential from the regulator input lead, through a diode and transistor, to the regulator output lead, providing the circuit to the rotor (field) winding. The "control circuit" consists of a voltage sensitive zener diode, drive transistor and a voltage divider network. The "control circuit" directs the transistor in the "load circuit" to turn off and on at a rate that will provide the required charging voltage.
A solenoid is a magnetic switch that utilizes low current to close a high current circuit. The solenoid has an electromagnet with a movable core. There are contacts on the end of the core. The contacts are held open by a spring that pushes the core away from the magnetic center of the coil. Low current will energize the coil and form a magnetic field. The magnetic field draws the core to the center of the coil and the contacts close.
SCHEMATIC OF A SOLENOID
1. Coil. 2. Switch terminal. 3. Battery terminal. 4. Contacts. 5. Spring. 6. Core. 7. Component terminal.
The starting motor is a device used to rotate the flywheel of an engine fast enough to start the engine.
STARTING MOTOR CROSS SECTION
1. Field. 2. Solenoid. 3. Clutch. 4. Pinion. 5. Commutator. 6. Brush assembly. 7. Armature.
The starting motor used with direct electric start incorporates a solenoid. The action of the solenoid engages the pinion with the ring gear on the engine flywheel, when the solenoid is energized. The pinion always engages before the electric contacts in the solenoid closes the circuit between the battery and the starting motor. An overrunning clutch protects the starting motor from being overspeeded. Releasing the start-switch disengages the pinion from the ring gear on the flywheel.
A variety of electrical systems can be used with these engines. Some systems are available with one 32 volt, 24 volt or 12 volt starting motor. Where 30 volt (15 cell battery) system is used, the 32 volt diagram applies. Other systems without electric starting motors are provided for use with air starting and hydraulic starting.
Glow plugs provide for low temperature starting. Glow plugs are not required where ideal starting conditions exist. These diagrams show only the HEAT-START switch with glow plugs. Systems without glow plugs use a push button switch with two post connections to energize the starter solenoid.
A fuel pressure switch in all systems prevents alternator field excitation. Thus damage to the alternator from the battery is prevented when the engine is not operating.
Automatic START-STOP wiring diagrams are shown for the complete system in the ATTACHMENT section of this manual.
Negative Ground Systems
These systems are most often used in applications where no special precautions are necessary to prevent local radio interference and/or electrolysis of grounded components.
NEGATIVE GROUND 24V: 60 AMP. AND 32V: 60 AMP. SYSTEM WITH GLOW PLUGS (DELCO REMY)
NEGATIVE GROUND 24V: 35 AMP. OR 12V: 35 AMP. SYSTEM WITH GLOW PLUGS (MOTOROLA)
NEGATIVE GROUND 24V: 45 AMP. OR 12V: 60 AMP. SYSTEM WITH GLOW PLUGS (DELCO REMY)
NEGATIVE GROUND 24V: 60 AMP. OR 32V: 60 AMP. SYSTEM WITH GLOW PLUGS FOR USE WITH AIR OR HYDRAULIC STARTING (DELCO REMY)
INSULATED 24V: 60 AMP. OR 32V: 60 AMP. SYSTEM WITH GLOW PLUGS (DELCO REMY)
INSULATED 24V: 35 AMP. OR 12V: 35 AMP. SYSTEM WITH GLOW PLUGS (MOTOROLA)
INSULATED 24V: 60 AMP. OR 32V: 60 AMP. SYSTEM WITH GLOW PLUGS FOR USE WITH AIR OR HYDRAULIC STARTING (DELCO REMY)