Table of Contents
Advertisement
6A1-2
1977 PONTIAC SERVICE MANUAL
FIG. 6A1-1 CYLINDER BLOCK
FIG. 6A1-2 OIL FILTER AND DISTRIBUTOR OILING
The main head oil gallery is rifle drilled down the right hand
side of the head.
PISTONS AND CONNECTING
RODS
The pistons are made of cast aluminum alloy having an
outer iron coating of .0005" min. Two compression rings and
one oil control ring are used for positive piston to wall sealing.
Piston pins are offset 1/16" toward the thrust side (right hand
side) to provide a gradual change in thrust pressure against
the cylinder wall as the piston travels its path. Piston pins are
Chromium steel and have a floating fit in the pistons. They
are retained in the connecting rods by a press fit. Connecting
rods are made of forged steel. Full pressure lubrication is
directed to the connecting rods by drilled oil passages from
the adjacent main bearing journal. Oil holes at the connecting
rod journals are located so that oil is supplied to give maxium
lubrication just prior to full bearing load.
VALVE TRAIN
An overhead cam, direct action design is used. Motion
is transmitted from the camshaft through the hydraulic lifter
to the valve.
HYDRAULIC VALVE LIFTERS
Hydarulic Valve Lifters are used to keep all parts of the
valve train in constant contact. The hydraulic lifter assembly
consists of: the lifter body, which rides in the cylinder head
boss, a plunger, a metering valve, a plunger spring, a check
ball and a check ball retainer. When the lifter is riding on the
low point of the cam, the plunger spring and oil pressure
keeps the plunger in contact with the valve stem. When the
lifter body begins to ride up the cam lobe, the check ball cuts
off the transfer of oil from the reservoir below the plunger.
The plunger and lifter body then move as a unit, pushing the
valve open. As the lifter body rides down the other side of
the
cam,
the plunger follows with it until the valve closes. The
lifter body continues to follow the cam to its low point, but
the plunger spring keeps the plunger in contact with the
valve. The ball check valve will then move off its seat and
its lifter reservoir will remain full.
INTAKE MANIFOLD
The intake manifold is of cast iron single level design for
efficient fuel distribution. The carburetor pad is centrally
located. An
EGR
port is also cast into the manifold for the
induction of exhaust gases into the inducted fuel air mixture.
EXHAUST MANIFOLD
The cast iron exhaust manifold directs the exhaust gasses
from the combustion chamber to the vehicle exhaust system.
A sheet metal heat stove preheats the air drawn into the air
cleaner during cold operation for better fuel vaporization.
COMBUSTION CHAMBERS
Combustion Chambers are cast to insure uniform shape
for all cylinders. Spark plugs are located on the right hand
side between the intake and exhaust valves.
ENGINE SERVICE
The following information is important in preventing
engine damage and in contributing to reliable engine
performance. When raising or supporting the engine for any
Advertisement
Table of Contents
