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6A4-8
1977 PONTIAC SERVICE MANUAL
1. LUBR ICATE ENTIRE BOLT
I N ENGINE OIL.
2. TORQUE ALL BOLTS I N
SEQUENCE SHOWN TO 15 FT. LBS.
3. RE-TORQUE I N SEQUENCE SHOWN
TO 40 FT. LBS.
4640
Fig. 6A4-1
1
Intake Manifold Torque Sequence
2. Remove rocker arm, flanged bolts, pivot and rocker
arms.
NOTE: Remove each set (one set per cylinder) as a unit.
Installation
1. Position a set of rocker arms (for one cylinder) in the
proper location.
2. Lubricate wear points with 1050169 Lubricant or
equivalent and install the pivots.
3. Install the hardened flanged bolts and tighten
alternately. Torque bolts to 25 ft. lbs.
REPLACING VALVE SPRING
(HEAD ON ENGINE)
To replace a worn or broken valve spring without
removing the cylinder head proceed as follows:
Removal
1. Remove rocker arm assemblies.
2. Remove spark plug and install Tool BT-72-1-B into
spark plug hole and attach to an air hose to hold the valve
against its seat.
3. Install Tool BT-64 13 (Fig. 6A4- 16) and compress the
valve spring until valve keys are accessible; then remove keys,
valve rotators and springs.
NOTE: If valve spring does not compress, tap tool with
a mallet to break bind at rotator and keys.
CHECKING ROTATORS
The rotators cannot be disassembled and require
replacement only when they fail to rotate the valve.
Rotator action can be checked by applying a daub of
paint across the top of the body and down the collar. Run
engine approximately 1500 rpm, there should appear to be
motion between the body and collar, the body will appear to
"walk" around the collar. Rotator action can be either
clockwise or counterclockwise, sometimes on removal and
reinstallation; the direction of rotation will change but this
does not matter so long as it rotates.
Anytime the valves are removed for service the tips
should be inspected for improper pattern which could
indicate valve rotator malfunction. See Figure 6A4-17.
Installation
1. Install valve spring and rotor. Using Tool BT 6413,
compress the valve spring until the valve keys can be
installed.
2. Install spark plugs. Torque to 25 lbs. ft.
3. Install rocker arm assemblies.
VALVE LIFTERS
Operation
Oil is supplied to the lifter through a hole in the side of
the lifter body which indexes with a groove and hole in the
lifter plunger. Oil is then metered past the oil metering valve
in the lifter, through the push-rods to the rocker arms. (Fig.
6A4- 1 8)
When the lifter begins to ride up the cam lobe, the ball
check is held against its seat in the plunger by the ball check
spring which traps the oil in the base of the lifter body below
the plunger. The plunger and lifter body then raise as a unit,
pushing up the push-rod to open the valve. The force of the
valve spring which is exerted on the plunger through the
rocker arm and push-rod causes a slight amount of leakage
between the plunger and lifter body. This "leak-down" allows
a slow escape of trapped oil in the base of the lifter body. As
the lifter rides down the other side of the cam lobe and
reaches the base circle or "valve closed" position, the plunger
spring quickly moves the plunger back (up) to its original
position. This movement causes the ball check to open against
the ball spring and oil from within the plunger is drawn into
the base of the lifter. This restores the lifter to zero lash.
Removal
NOTE: Valve lifters and push-rods should be kept in
order so they can be reinstalled in their original position.
Some engines will have both standard and .010" oversize
valve lifters, the .010" oversize lifter is etched
" 0
in the
side of the lifter. The cylinder block will also be marked
if the oversize lifter is used. (Fig. 6A4-19)
1. Remove intake manifold and gasket.
2. Remove valve covers, rocker arm assemblies and
push-rods.
3. If lifters are varnished, apply carburetor cleaning
solution to the lifter body. Allow five minutes for solution to
remove varnish.
C A UTI 0 N
:
Carburetor cleaning solvent should
be used in a well ventilated room. A void contact
with skin and prolonged breathing of fumes.
4. Remove lifters. Use of Tool BT-6407 will aid in
removal of varnished lifters. See Figure 6A4-19.
Disassembly
1. Remove retainer ring with small screwdriver.
2. Remove push-rod seat and oil metering valve.
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