The fuel system is designed to use fuel to cool and lubricate the injection pump and injectors. Fuel is
continually vented from the injection pump and a small amount of fuel leaks by the injector needle valve during injection.
Any leakage past the needle valve enters the fuel drain manifold, which routes fuel back into the fuel tank.
The fuel/water separator is equipped with a valve which can be opened regularly to drain collected water.
Regular maintenance, including draining moisture from the fuel/water separator and supply tanks, is essential to keep
water out of the fuel.
The Lucas CAV DPA fuel injection pump is a rotary distributor pump. The pump uses a coded spring
connection to change the governor setting. The amount of fuel injected and subsequently the speed and power from the
engine is controlled by the fuel control lever.
The injection pump idle adjustment screw provides a stop for the lever at low speed. The screw can be used
to increase idle speed for accessory loading or, if required, to lower idle speed. The pump is equipped with a mechanical
shut down lever. This lever is spring-loaded in the run position.
Engine Cooling System. The function of the engine cooling system (Figure 1-8) is to maintain a specified
operating temperature for the engine. Heat generated by the engine is absorbed by coolant flowing through passages in
the cylinder block and cylinder head.
Heat is removed from the coolant as it flows through the radiator. The high temperature engine coolant
circulates through tubes in the radiator, while cool air is blown across the tubes by the cooling fan. The resulting lower
temperature coolant is drawn from the radiator to the engine by an integrally mounted water pump.
The water pump empties coolant into the coil cooler cavity of the cylinder block. The coolant circulates
around each cylinder and crosses the block to the fuel pump side of the engine. The coolant flows up into the cylinder
head and crosses over the valve bridges. As the coolant flows across the head it provides cooling for injector nozzles.
The coolant passes down the exhaust manifold side of the engine to the integral thermostat housing.
When the engine is below operating temperature, the thermostat is closed, and the coolant flow bypasses the
radiator and goes to the water pump inlet via internal drillings in the block and cylinder head. When operating temperature
is reached, the thermostat opens, blocking the bypass passage to the water pump and opening the outlet to the radiator.
The water pump is belt driven from the crankshaft pulley. An automatic belt tensioner is used to prevent the
belt from slipping on the pump pulley.
Air System. The engine air system consists of two air cleaners/filters, air inlet hose, intake manifold, and
exhaust manifold (refer to Figure 1-2 for component location).
Intake air flows directly from the air cleaner to the intake manifold. From the intake manifold, air is pulled into
the cylinder and used for combustion. After combustion it is forced out of the cylinders through the exhaust manifold.