Oil Pump; Oil Pressure Regulator (Relief Valve); Oil Filter - Toyota 22R-E Service Manual

EG1–233
ENGINE – LUBRICATION SYSTEM
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 and oil filter, etc. 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 gravity to the oil pan. A dipstick on the side of the oil
pump body is provided to check the oil level.

OIL PUMP

The oil 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 to remove impurities. The
oil pump itself is an internal 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 same direction. When both gears
rotate, the space between the two gears changes. Oil is draw in when this space widens, and is
discharged when the space becomes narrow.

OIL PRESSURE REGULATOR (RELIEF VALVE)

At high engine speeds, the oil pump supplies more oil to each part than is necessary. For this
reason, an oil pressure regulator which works to prevent an oversupply oil is installed on the
oil pump. During normal oil supply, a coil spring and valve keep the by–pass closed, but when too
much oil is being supplied, the pressures become extremely high, over powering the force of the
spring and opening the valve. This allows the excess oil to flow through the relief valve and return
to the oil pan.

OIL FILTER

The oil filter is a full flow type with– a paper filter element and built–in relief valve. Particles of
metal from wear, airborne dirt, carbon and other impurities can get in the oil during use and could
cause accelerated wear or seizing 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 element
becomes clogged with impurities. The relief valve opens when the oil pressure overpowers the
force of the spring. Oil passing through the relief valve by–passes the oil filter and flows directly
into the main oil hole in the engine.