G643 (E) Service Manual Chapter 3. Engine Mechanical System
57
Engine Lubrication
General Description
Full pressure lubrication, through a full-flow oil filter
is supplied by a gear-type oil pump. Oil is drawn up
through the oil pump screen and passes through the
pump to the oil filter. The oil filter is a full-flow paper
element unit with an anti-drain back valve. An oil
filter bypass valve is used to ensure adequate oil
supply in the event the filter becomes plugged or
develops excessive pressure drop.
Figure 12-1 Engine Lubrication Flow
Filtered oil flows into the main gallery and then to
the camshaft, balance shaft, rear bearing, and
crankshaft bearings. The valve lifter oil gallery
supplies oil to the valve lifters. Oil flows from the
valve lifters through the hollow valve pushrods to the
rocker arms. Oil drains back to the crankcase
through oil drain holes in the cylinder head. The
camshaft timing chain is drip fed from the front
camshaft bearing. The pistons and piston pins are
lubricated by oil splash.
