Valve Mechanism; Valve Stem Oil Seal And/Or Valve Spring - Chevrolet LIGHT DUTY TRUCK (SERIES 10-35) Service Manual

6A 1-12 IN-LINE 6
2. Install dipstick tube bracket.
3. Connect three rear plug wires to appropriate spark
plugs.
4. Connect battery negative cable.

VALVE MECHANISM

Removal
1. Remove rocker arm cover as outlined.
2. Remove rocker arm nuts, rocker arm balls, rocker
arms and push rods.
NOTICE: Place rocker arms, rocker arm balls and
push rods in a rack so that they may be reinstalled in
the same location.
Installation and Adjustment
Whenever new rocker arms and/or rocker
NOTICE:
arm balls are being installed, coat bearing surfaces of
rocker arms and rocker arm balls with "Molykote" or
its equivalent.
1 . Install push rods. Be sure push rods seat in lifter
socket.
2. Install rocker arms, rocker arm balls and rocker arm
nuts. Tighten rocker arm nuts until all lash is eliminated.
3. Adjust valves when lifter is on base circle of camshaft
lobe as follows:
a. Mark distributor housing, with chalk, at # 1 and
positions (plug wire) then disconnect plug wires at spark
plugs and coil and remove distributor cap and plug wire
assembly (if not previously done).
b. Crank engine until distributor rotor points to #1
cylinder position. The following valves can be adjusted with
engine in # 1 firing position:
# 1 cylinder-Exhaust and Intake.
cylinder-Intake
#2
# 3 cylinder-Exhaust
# 4 cylinder-Intake
# 5 cylinder-Exhaust
c. Back out adjusting nut until lash is felt at the push
rod then turn in adjusting nut until all lash is removed. This
can be determined by rotating the push rod while turning
adjusting nut (Fig. 6A1-10). When play has been removed,
turn adjusting nut in one full additional turn (to center lifter
plunger).
d. Crank engine until distributor rotor points to
position. The following valves can be adjusted with engine
in firing position:
#6
# 2 cylinder-Exhaust
# 3 cylinder-Intake
# 4 cylinder-Exhuast
# 5 cylinder -Intake
#6 cylinder-Intake and Exhuast
4. Install distributor cap and spark plug wire assembly.
5. Install rocker arm cover as outlined.
6 . Adjust carburetor idle speed.
LIG H T T R U CK SER V ICE MANUAL
Fig. 6 A 1 -1 0 -V a lv e A d ju stm e n t
VALVE STEM OIL SEAL AND/OR VALVE
SPRING
Replacement
1. Remove rocker arm cover as previously outlined.
#6
2. Remove spark plug, rocker arm and push rod on the
cylinder(s) to be serviced.
3. Install air line adapter Tool J-23590 to spark plug
port and apply compressed air to hold the valves in place.
4. Using Tool J-5892 to compress the valve spring,
remove the valve locks, valve cap, valve shield and valve
spring and damper (fig. 6A1-11).
5. Remove the valve stem oil seal.
. To replace, set the valve spring, valve shield and
6
#6
Fig. 6A1-1 1-Compressing Valve Spring