Chevrolet 1977 light duty truck, Service Manual

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Fig. 6A 11 -Cylinder Head To Exhaust M anifold
T igh te n in g Sequence
Converter, attach exhaust pipe and align exhaust system.
T orque attaching bolts to specification.
7. Lower vehicle.
8. Install power steering p u m p a n d / o r A.I.R. p u m p
and brackets, if so equipped. Tighten drive belt using
strand tension gauge.
9. Install air cleaner.
10. Connect negative battery cable.
11. Start engine and check for leaks.
ROCKER A RM COVER
Removal
1. Disconnect crankcase ventilation hose(s) at
rocker arm cover.
2. Remove air cleaner.
3. Disconnect all wires, fuel and vacuum pipes
from rocker arm cover clips.
4. Disconnect air injection hose from check valve
o f AIR pipe (where so equipped).
5. Remove rocker arm cover by rotating out from
u n d e r air pipe.
CAUTIO N: Do not p ry rocker arm cover loose.
Gaskets adhering to cyllinder head and rocker
arm cover m ay be sheared by bum ping fro n t
en d o f rocker arm cover rearward with palm o f
ha n d or rubber mallet.
Installation
1. Clean gasket surfaces on cylinder head with
degreaser. U sing RTV, install rocker arm cover and
torque bolts to specification.
N O T E : All loose RTV sealer, or pieces causing
installation interference must be removed from
both cylinder head an d cover seal surfaces p rio r to
applying new sealer.
A 1 /8 " bead o f RTV sealer should be placed all
aro u n d the rocker cover sealing surface o f the
cylinder head. (W h en going around attaching bolt
holes, always go around the in b o ard side o f the
holes). Install cover and torque bolts to specifica­
tion while RTV is wet (within 10 min.).
2. C onnect wires, fuel and vacuum pipes at rocker
arm cover clips.
3. Install air cleaner.
4. Connect crankcase ventilation hoses and AIR
hoses.
VALVE M E C H A N IS M
Removal
1. Remove rocker arm cover as outlined.
2. Remove rocker arm nuts, rocker arm balls,
rocker arms and push rods.
NOTE: Place rocker arms, rocker arm balls and
push rods in a rack so that they m ay be reinstalled
in the same location.
Installation and Adjustment
NOTE: W henever new rocker arm s a n d / o r rocker
arm balls are being installed, coat bearing surfaces
o f rocker arm s
and rocker arm balls with
"M o ly k o te" or its equivalent.
1. Install push rods. Be sure push rods seat in lifter
socket.
2. Install rocker arms, rocker arm balls an d rocker
arm nuts. T ighten rocker arm nuts until all lash is
eliminated.
3. Adjust valves w hen lifter is on base circle o f
cam shaft lobe as follows:
a. M ark distributor housing, with chalk, at
n u m b e r one and n u m b e r six 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
n u m b e r one cylinder position. The following valves can
be adjusted with engine in n u m b er one firing position:
N u m b e r one cylinder-Exhuast and Intake.
N u m b e r two cylinder-Intake
N u m b e r three cylinder-Exhaust
N u m b e r four cylinder-Intake
N u m b e r five 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. Theis can be determ ined by checking push rod
end play while turning adjusting nut (Fig. 6A-12). W hen
play has been removed, turn adjusting nut in one full
additional turn (to center lifter plunger).
d. C rank engine until distributor rotor points to
n u m b e r six position. The following valves can be
adjusted with engine in n u m b e r six firing position:
N u m b e r two cylinder-Exhaust
N u m b e r three cylinder-Intake
N u m b e r four cylinder-Exhuast
N u m b e r five cylinder -Intake
N u m b e r six cylinder-Intake and Exhuast
4. Install distributor cap and spark plug wire
assembly.
5. Install rocker arm cover as outlined.
6. Adjust carb u reto r idle speed.
VALVE STEM OIL SEAL A N D /O R VALVE
SPR IN G
Replacement
18/23
LBS F T
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