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8-24
GROUP 8-
ENGINE
FIG. 3-TYPICAL
i
Sectional View
bly through a drilled passage in the
cylinder block at the No. 4 camshaft
bearing. The oil is metered by a
groove in the camshaft journal. The
passage in the block indexes with
&.
hole in the cylinder head. The oil
passage in the cylinder bead is drilled
from the cylinder head bolt bore to
the No. 6 valve rocker arm shaft
support. The rocker arm shaft sup-
ports have a square cored bolt
mounting hole for more positive
lubrication of the rocker arms, shafts
and
valves.
The oil flows through the
valve rocker arm shaft through
drilled holes in each rocker arm to
lubricate the valve and the push
rod end of the rocker arm. The ·ex-
cess oil spirals down the rotating
push rod and assists in lubricating
the tappet and push rod seat. An
oil outlet in the
No.
1 rocker arm
shaft support, exhausts excess oil
from the valve rocker arm shaft.
The oil from each rocker arm drains
into the push rod chamber through
the push rod bore holes in the cylin-
der head.
The oil in the push rod chamber
drains back into the oil pan through
cored openings in the block.
POSITIVI
CRANKCASE VENTILATION
SYSTEM
The air flow in the positive crank-
A2293·A
case ventilation system is shown in
Fig.
5.
Ventilating air enters the engine
through the oil filler cap located on
the front of the valve rocker arm
cover.
The filler cap contains a filter-
FIG. 4-Hydraulic Valve lifter Operation
ing element which filters the incom-
ing air.
From the oil filler cap, the air
flows into the front section of the
valve rocker arm shaft chamber. The
ventilating air moves down past the
push rods and into the crankcase.
Air is diverted from the front sec-
tion of the crankcase through holes
in the front of the cylinder block
wall to ventilate the timing chain
chamber.
The rotating action of the crank-
shaft causes the air to flow towards
the rear of the crankcase and up into
the rear section of the valve rocker
arm cover. The air then enters a
spring-loaded regulator valve that
regulates the amount of air flow to
meet changing operating conditions.
The air is then directed to the intake
manifold through the crankcase vent
hose and the spacer fitting.
During
idle,
intake
manifold
vacuum is high. The high vacuum
overcomes the tension of the spring
pressure and moves the valve to a
low flow position (Fig. 7). With the
valve in this position, all the venti-
lating air passes through the re-
stricted passage in the valve. With
the valve in this position, there is
minimum
ventilation.
As engine
speed
increases
and
manifold
vacuum decreases, the spring forces
the valve out of the passage and to
the full open position (Fig. 7 ). This
increases the flow of ventilating air.
7"0C'
OIL GALLERY
A2132-B
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