TM 5-3810-300-24 & P2
Oil for lubricating the connecting rod bearings, piston pins, and for cooling the piston head, is provided through the drilled
hole in the crankshaft from the adjacent forward main bearings. The gear train is lubricated by the overflow of the oil
from the camshaft pocket through a connecting passage into the flywheel housing. A certain amount of oil spills into the
flywheel housing from the camshaft, balance shaft, and idler gear bearings. The blower drive gear bearing is lubricated
through an external pipe from the rear horizontal oil passage of the cylinder block.
Oil from the cam pocket enters the blower and overflows through two holes, one at each end of the blower housing,
providing lubrication for the blower drive gears at the rear end, and for the governor mechanism at the front.
Oil Filters.
Engines are equipped with a full-flow type, lubricating oil filter. If additional filtering is required, a by-pass oil filter may
also be installed.
The full-flow filter assembly can be remotely mounted or mounted on the engine. A by-pass valve, which opens at 18 to
21 psi, is located in the filter adaptor to ensure engine lubrication in the event the filter should become plugged.
All of the oil supplied to the engine passes through the full-flow filter that removes the larger foreign particles without
restricting the normal flow of oil.
The by-pass filter assembly, when used, continually filters a portion of the lubricating oil that is being bled off the oil
gallery when the engine is running. Eventually all the oil passes through the filter, filtering out minute foreign particles
that may be present.
Some engines may be equipped with a by-pass filter assembly consisting of two filter elements, each enclosed in a shell
which is mounted on a single adaptor. An oil passage in the filter adaptor connects the two annular spaces surrounding
both filter elements.
Low Oil Pressure Switch.
A low oil pressure switch is on the engine. When a low oil pressure condition exists, the pressure switch sends a electrical
signal to the low oil pressure indicator located in the cab.
Cooling System Components. (Illus. 4-7).
The engine coolant is drawn from the bottom of the radiator core by the water pump and forced through the oil cooler and
into the cylinder block. The coolant circulates up through the cylinder block into the cylinder head, then to the water
manifold and thermostat housing. From the thermostat housing, the coolant returns to the radiator and passes down a
series of tubes, and is cooled by the air stream created by the fan.
When starting a cold engine or when the coolant is below operating temperature, the coolant is restricted at the
thermostat housing and a by-pass tube provides water circulating within the engine during the warm-up period.
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