TM 5-3810-300-24&P-3
4
SECTION 4
LUBRICATION SYSTEM
CONTENTS
Lubrication System ...........................................................................................................................
Lubricating Oil Pump ........................................................................................................................
Lubricating Oil Pressure Regulator .................................................................................................
4.11
Lubricating Oil Filters .......................................................................................................................
Lubricating Oil Cooler.......................................................................................................................
Oil Level Dipstick ..............................................................................................................................
Oil Pan ................................................................................................................................................
Ventilating System ............................................................................................................................
Specifications - Service Tools .........................................................................................................
LUBRICATION SYSTEM
Figure 1 schematically illustrates the flow of oil through a
is installed in the lubricating system between the pump
typical Series 71 lubricating system including the various
and the cooler, all of the oil is filtered before entering the
components such as the oil pump, oil cooler, by-pass
engine.
and full-flow filters, the pressure regulator valve and by-
pass valve.
A by-pass type filter with replaceable element is available
as optional equipment. A portion of the oil is continually
The lubricating oil is circulated by a gear-type pressure
by-passed through the filter and the filtered oil is returned
pump mounted on the No. 1 and No. 2 main bearing
to the engine oil pan.
caps and gear driven from the crankshaft.
Stabilized oil pressure is maintained within the engine at
All the oil leaving the pump is forced through the full-flow
all speeds, regardless of the oil temperature, by means
oil filter to the cooler and then into the oil gallery in the
of a regulator valve located between the pump outlet and
cylinder block from where it is distributed to the various
the inlet to the cylinder block. When the oil pressure at
engine bearings. The drain from the cylinder head and
the valve exceeds 50 psi (345 kPa), the regulator valve
other engine parts leads back to the oil pan.
opens and remains open until the pressure is less than
the opening pressure.
A spring-loaded integral plunger-type relief valve, located
in the oil pump body, by-passes excess oil from the
discharge to the intake side of the pump when the
pressure in the engine oil gallery exceeds approximately
105 psi (724 kPa).
Oil from the cooler is conducted by a vertical passage to
a longitudinal main oil gallery on the blower side of the
If the oil cooler should become clogged, the oil will flow
cylinder block. As shown in Fig. 1, this gallery distributes
from the pump through a spring-loaded by-pass valve
the oil, under pressure, to the main bearings and to a
directly into the oil gallery.
horizontal, transverse passage at each end of the
cylinder block. From each of these two horizontal
Clean engine oil is assured at all times by the use of a
passages, oil flows through two vertical bores (one at
replaceable element type full-flow oil filter incorporated in
each end of the cylinder block) to the end bearings of the
the engine lubrication system. With this type filter, which
camshaft and balance shaft. In addition, oil is forced
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