Pontiac FIREBIRD 1972 Service Manual page 576

6-64 1972 PONTIAC SERVICE MANUAL
4. Loosen rocker arm ball nut and move rocker arm off
push rod.
5. Remove push rod.
6. Remove lifter. Hydraulic valve lifter remover J 3049
may facilitate removal of lifter.
If more than one lifter is to be replaced, store push
rods in a stand and lifters in a lifter box so they can
be re-installed in exactly the same place and position.
See GENERAL INFORMA TION ON ENGINE
SER VICE.
REPLACE
If new lifter is to be installed, be sure to remove all sealer
coating from inside of new lifter and check leak-down
rate.
1. Place new lifter in lifter boss.
2. Replace push rod exactly as removed (same end
against rocker arm).
NOTE: Whenever rocker arms and/or rocker
arm balls are being installed, coat bearing sur-
faces of rocker arms and rocker arm balls with
"Molykote" or its equivalent.
3. Position rocker arm on push rod and on all but 307
engine, tighten rocker arm ball retaining nut to 20 lb.
ft.
4. On 307 engine, adjust valves when lifter is on base
circle of camshaft lobe as follows:
Fig. 6-105 Adjusting Valve Train Lash - 307 Engine
c. With the engine in the number 1 firing position as
determined above, the following valves may be
adjusted.
Exhaust
-
1 , 3, 4, 8
Intake
-
1, 2, 5, 7
d. Crank the engine one revolution until the pointer
"0" mark and harmonic balancer mark are again
in alignment. This is number 6 firing position.
With the engine in this position the following
valve may be adjusted.
a. Crank engine until mark on harmonic balancer
lines up with center or "0" mark on the timing tab
Exhaust
-
2, 5, 6, 7
and the engine is in the number 1 firing position.
This may be determined by placing fingers on the
Intake
-
3, 4, 6, 8
number 1 cylinder valves as the mark on the
damper comes near the "'0'mark on the front
5. Replace rocker arm cover.
cover. If the valves are not moving, the engine is
in the number 1 firing position. If the valves move
6. On all but 307 engine, inspect condition of push rod
as the mark comes up to the timing tab, the engine
cover gasket and replace if necessary; replace push
is in number 6 firing position and crankshaft
rod cover and tighten screws. New gasket must be
should be rotated one more revolution to reach
cemented securely to push rod cover before installa-
the number 1 position.
tion.
b. Valve adjustment is made by backing off the ad-
7. Replace intake manifold using new gaskets and re-
justing nut (rocker arm stud nut) until there is
place O-ring seal.
play in the push rod and then tighten nut to just
remove all push rod to rocker arm clearance. This
VALVE LIFTER
may be determined by rotating push rod with
fingers as the nut is tightened (Fig. 6-105). When RECONDITION
push rod does not readily move in relation to the
rocker arm, the clearance has been eliminated.
Because of the important part hydraulic valve lifters play
The adjusting nut should then be tightened an
in the operation of an engine and the close tolerances to
the hydraulic lifter
which they are manufactured, proper handling, and above
travel. No other ad-
all, cleaniness, cannot be overstressed when servicing
these parts.