Chevrolet Light Duty Truck 1973 Service Manual page 350

6 -1 4 ENGINE
Fig. 21—Valve Adjustment (L6 Engine)
with fingers as the nut is tightened (fig.
When push rod does not readily move in
relation to the rocker arm, the clearance has
been eliminated. The adjusting nut should then
be tightened an additional
hydraulic lifter plunger in the center of its
travel. No other adjustment is required.
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 " " mark and torsional damper mark
0
All engines operate on the 4-stroke cycle principle (Fig.
ID and 2D). During this cycle the piston travels the
length of its stroke four times. As the piston travels the
length of its stroke (up or down) the crankshaft is
rotated halfway (180 degrees). To accomplish one cycle
of the -stroke cycle, the crankshaft rotates two complete
4
).
22
turn to place the
1
THEORY OF OPERATION
Fig. 22—Valve Adjustment (V8 Engine)
are again in alignment. This is number
position. With the engine in this position the
following valve may be adjusted.
Exhaust - 2, 5, , 7
6
Intake - 3, 4, ,
6 8
4. Clean gasket surfaces on cylinder head(s) and
rocker arm cover(s) with degreaser, then install
rocker arm cover(s), using new gasket(s), and torque
bolts to specifications.
5. Install distributor cap and spark plug wire
assembly.
. Install rocker arm cover as outlined.
6
7. Adjust carburetor idle speed.
turns; the camshaft, which controls the valves, is driven
by the crankshaft at half crankshaft speed. Valve action,
intake and exhaust, occurs once in each 4-stroke cycle
and the piston acts as an air pump during the two
remaining strokes.
firing
6
LIGHT DUTY TRUCK SERVICE MANUAL