TM 5-3810-300-24&P-3
4.2
Series 71 engines are equipped with a full-flow type
By-Pass Oil Filter
lubricating oil filter. A by-pass type oil filter may be used
in addition to the full-flow type filter when additional
When additional filtration is desired, an oil filter of the by-
filtration is desired.
pass type (Fig. 2) may also be installed on the engine.
However, the size of the orifice on the discharge side of
Full-Flow Oil Filter
the filter must not exceed .062" to control the oil flow rate
and to provide sufficient oil pressure when the engine is
The full-flow type lubricating oil filter is installed ahead of
running at idle speed.
the oil cooler in the lubrication system. The filter may be
remotely mounted or mounted on the engine as shown in
When the engine is running, a portion of the lubricating
Fig. 1.
oil is bled off the oil gallery and passed through the by-
pass filter. Eventually all of the oil passes through the
The filter assembly consists of a replaceable element
filter, filtering out fine foreign particles that may be
enclosed within a shell which is mounted on an adapter
present.
or base. When the filter shell is in place, the element is
restrained from movement by a coil spring.
The by-pass filter assembly consists of a replaceable
element contained in a shell mounted on a combination
All of the oil supplied to the engine by the oil pump
base and mounting bracket. When the shell is in place,
passes through the filter before reaching the various
the filter element is restrained from
moving parts of the engine. The oil is forced by pump
pressure through a passage in the filter adapter to the
space surrounding the filter element. Impurities are
filtered out as the oil is forced through the element to a
central passage surrounding the center stud and out
through another passage in the filter adapter and then to
the oil cooler.
A valve, which opens at approximately 18-21 psi, is
located in the filter adapter or base and will by-pass the
oil directly to the oil cooler should the filter become
clogged.
Fig. 1. Typical Full-Flow Oil Filter Mounting
Fig. 2. Typical By-Pass Oil Filter Mounting
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