Rocker Arm Cover; Removal; Installation; Valve Mechanism - Chevrolet Light Duty Truck 1973 Service Manual

6 -2 6 ENGINE
manifold has distorted to a point where it will not
seat properly. If a good exhaust seal is to be
expected, the exhaust manifold must be replaced.
3. Reinstall the one bolt and two nuts at the center of
the manifold to finger tight.
4. Position new gasket over manifold end studs on the
cylinder head.
5. Install manifold assembly bolts and clamps while
holding manifold assembly in place by hand.
. Clean, oil and torque all manifold assembly-to-
6
cylinder head bolts and nuts to specifications.
7. Complete torqueing the inlet to exhaust manifold
bolt and two nuts at the center of the manifold to
specifications.
. Connect exhaust pipe to manifold using a new
8
packing.
9. Connect crankcase ventilation hose at rocker arm
cover.
10. Connect exhaust gas recirculation valve hose.
11. Connect fuel and vacuum lines at carburetor.
12. Connect throttle rods at bellcrank and install
throttle return spring.
13. Install air cleaner, start engine, check for leaks and
adjust carburetor idle speed.

Rocker Arm Cover

Removal

1. Disconnect crankcase ventilation hose(s) at rocker
arm cover.
2. Remove air cleaner.
3. Disconnect temperature wire from rocker arm cover
clips.
4. Remove air injection pipe support bracket.
5. Remove rocker arm cover.

Installation

1. Clean gasket surfaces on cylinder head and rocker
gasket, install rocker arm cover and torque to
specifications.
2. Connect temperature wire at rocker arm cover clips.
3. Install air cleaner.
4. Connect crankcase ventilation hoses.
5. Install air injection pipe support bracket.

Valve Mechanism

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 may be
reinstalled in the same location.

Installation and Adjustment

NOTE: Whenever new rocker arms and/or
rocker 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 number
one and number six cylinder 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
number one cylinder position and breaker
points are open. The following valves can be
adjusted with engine in number one firing
position.
Number one cylinder-Exhaust and Intake
Number two cylinder-Intake
Number three cylinder-Exhaust
Number four cylinder-Intake
Number 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. This can be determined by checking
push rod side play while turning adjusting nut
(fig. L). When play has been removed, turn
6
adjusting nut in one full additional turn (to
center lifter plunger).
d. Crank engine until distributor rotor points to
number six position and breaker points are
open. The following valves can be adjusted with
engine in number six firing position:
Number two cylinder-Exhaust
Number three cylinder-Intake
Number four cylinder-Exhaust
Number five cylinder-Intake
Number six cylinder-Intake and Exhaust
4. Install distributor cap and spark plug wire
assembly.
5. Install rocker arm cover as outlined.
. Adjust carburetor idle speed.
6

Valve Lifters

Hydraulic valve lifters very seldom require attention.
LIGHT DUTY TRUCK SERVICE MANUAL