Chevrolet 1977 light duty truck, Руководство по обслуживанию

Страница: 494 / 861

the d a m p e r comes n e a r the " O " mark on the crankcase
fro n t cover. If the valves are not moving, the engine is in
the n u m b e r 1 firing position. If the valves move as the
m ark comes up to the tim ing tab, the engine is in
n u m b e r 6 firing position an d should be turned over one
m ore time to reach the n u m b e r 1 position.
b. W ith the engine in the n u m b e r 1 firing
position as d ete rm in e d above, the following valves m ay
be adjusted.
-- E x h a u s t - 1, 3, 4, 8
— I n t a k e - 1 , 2, 5, 7
c. Back out adjusting nut until lash is felt at the
push rod then tu rn in adjusting nut until all lash is
removed. This can be d eterm ined by checking push rod
side play while turning adjusting nut (fig. 6A-15V).
W h e n play has been removed, turn adjusting nut in one
full a d d itio n al tu rn (to center lifter plunger).
d. C rank the engine one revolution until the
p o in te r " o " m ark and torsional d a m p e r m ark are again
in alignm ent. This is n u m b e r 6 firing position. W ith the
engine in this position the following valves m ay be
adjusted.
— Exhaust—2, 5, 6, 7
— In ta k e —3, 4, 6, 8
4. Install rocker arm covers as previously outlined.
5. S tart engine and adjust carb u reto r idle speed.
VALVE STEM OIL SEAL a n d /o r VALVE
S P R IN G
Removal
1. R em o v e rocker a rm cover as previously
outlined.
2. Remove spark plug, rocker arm and push rod on
the cylinder(s) to be serviced.
3. Install air line a d a p te r 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 an d valve spring and
d a m p e r (fig. 6A-16V).
5. Remove the valve stem oil seal.
Installation
Sm all V8 Engines
1. Set the valve spring and dam per, valve shield
and valve cap in place. Compress the spring with Tool
J-5892 and install oil seal in the lower groove o f the
stem, m aking sure the seal is flat and not twisted.
NO TE: A light coat o f oil on the seal will help
prevent twisting.
2. Install the valve locks and release the com pres­
sor tool m aking sure the locks seat properly in the upper
groove o f the valve stem.
NOTE: G rease may be used to hold the locks in
place while releasing the compressor tool.
3. Install spark plug and torque to specification.
4. Install and adjust valve mechanism as previously
outlined.
M a rk IV V8 Engines
1. Install new valve stem oil seal (coated with oil)
in position over valve guide.
NO TE: Seal installation instructions are supplied