Oil Pump; Oil Pressure Regulator; Oil Filter - Toyota 7M-GE Repair Manual

LUBRICATION SYSTEM - Description
.,LU-3
A pressure feeding lubrication system has been
adopted to supply oil to the moving parts of this
engine. The lubrication system consists of an oil
pan, oil pump, oil filter and other external parts
which supply oil to the moving parts in the engine
block. The oil circuit is shown in the illustration at
the top of the previous page. Oil from the oil pan is
pumped up by the oil pump. After it passes
through the oil filter, it is fed through the various
oil holes in the crankshaft and cylinder block. After
passing through the cylinder block and performing
its lubricating function, the oil is returned by gra-
vity to the oil pan. A dipstick on the side of the
cylinder block is provided to check the oil level.
OIL PUMP
The oil pump pumps up oil from the oil pan and
sends it under pressure to the various parts of the
engine. An oil strainer is mounted in front of the
inlet to the oil pump. The oil pump itself is a gear
pump, which uses a drive gear and driven gear
inside the pump body. When the drive gear
rotates, the driven gear rotates in the opposite
direction.
When the gear teeth disengage oil is
drak\ n in, and when the gear teeth engage oil is
discharged.
OIL PRESSURE REGULATOR
At high engine speeds, the engine oil supplied
bY thr oil pump exceeds the capacity of the engine
10 utiiize it. For that reason, the oil pressure regula-
tor i\ ,>rks to prevent an oversupply of oil. During
norm.tl oil
supply,
a coil spring and valve keep the
bYPcls:s closed, but when too much oil is being fed,
the becomes extremely high, overpower-
9 the force of the spring and opening the valves.
This ;:ilows the excess oil to flow through the
Yalvtj :snd return to the oil pan.
Olii FILTER
The oil filter is a full flow type filter with a built-
in paper filter element. Particles of :metal 'from
wear, a&born dirt, carbon and other impurities can
get in the oil during use and could cause acceler-
ated wear or siezing if allowed to circulate through
the engine. The oil filter, integrated into the oil line,
removes these impurities as the oil passes through
it. The filter is mounted outside the engine to
simplify replacement of the filter element. A relief
valve is also included ahead of the filter element to
relieve the high oil pressure in case the filter ele-
ment becomes clogged with impurities. The relief
valve opens when the oil pressure overpowers the
force of the spring. Oil passing through the relief
valve bypasses the oil filter and flows directly into
the main oil hole in the engine.