j. Start the engine and check for leaks.
The oil filter bypass valve is inside the oil
filter mounting bolt. If the oil filter becomes so
dirty that it blocks oil flow to the engine, the
bypass valve routes unfiltered oil directly to
To remove the bypass valve, remove the oil
filter. T h e b y p a s s v a l v e c a n n o t b e
disassembled without damaging it, but you can
push on the end of the bypass ball inside the
valve (Figure 97) to make sure it moves freely
inside the valve.
OIL P U M P
The trochoid oil pump is geared to the
secondary shaft. The double rotor pump pulls
oil through a coarse mesh screen and pushes it
through the oil filter to trap fine particles. Ifthe
filter becomes clogged, a bypass valve routes
the oil-still dirty-around the filter.
From the filter, one oil line goes to the oil
pressure switch (Figure 98) and the relief valve
in the oil pan (Figure 99). The pressure switch
turns on the low oil pressure warning light
when the oil pressure drops below a safe
minimum. The relief valve limits engine oil
pressure by dumping oil back into the
crankcase when the pump pressure exceeds the
limit in Table 1.
The filtered oil follows several distribution
a. One route goes to the crankshaft main
bearings and big-end bearings, the spray
from which lubricates the cylinder walls
and the piston pins.
b. One route goes through an orifice and
leads to the camshaft journals; after the
oil leaves the camshaft journals it
lubricates the cam lobes and valve lifters.
c. One route goes through a spray nozzle to
the primary drive chain.
d. One route goes through an orifice to the
secondary shaft and starter clutch.
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