Chevrolet 1977 light duty truck, Service Manual

Page: 497 / 861

N O T E : Before installing lifters, coat the bottom o f
the lifter with " M o ly k o te" or its equivalent.
C Y LINDER HEAD ASSEMBLY
Removal
E Rem ove in take m an ifo ld as previously outlined.
2. Rem ove g enerator lower m ounting bolt and lay
unit aside.
3. R em o v e ex h au st m a n ifo ld s as previously
outlined.
4. If vehicle is equipped with A / C , remove A / C
com pressor an d forw ard m ou n tin g bracket. Lay unit
aside.
N O T E : On vehicles e quipped with A.I.R., discon­
nect the ru b b e r hosing at the injection tubing check
valve (fig. 6A-21V). In this m anner, the tubing will
not have to be removed from the exhaust manifold.
5. R em ove valve m ec h a n ism as previously
outlined.
6. D rain cylinder block o f coolant.
7. Remove cylinder head bolts, cylinder head and
gasket. Place cylinder head on two blocks o f wood to
prevent dam age.
Disassembly
1. W ith cylinder head removed, remove valve
rocker arm nuts, balls and rocker arm s (if not previously
done).
2. U sing Tool J-8062, compress the valve springs
(fig. 6A-22V) and remove valve keys. Release the
compressor tool and remove rotators or spring caps.
spring shields (if so equipped) springs an d spring
dam per, then remove oil seals and valve spring shims.
3. Remove valves from cylinder h ead an d place
them in a rack in their p ro p er sequence so that they can
be assembled in their original positions.
Cleaning
1. Clean all carbon from combustion cham bers
and valve ports using Tool J-8089 (fig. 6A-23V).
2. Thoroughly clean the valve guides using Tool
J-8101 (fig. 6A-24V).
3. Clean all carb o n and sludge from push rods,
rocker arms and push rod guides.
4. Clean valve stems and heads on a buffing wheel.
5. Clean carbon deposits from head gasket mating
surface.
Inspection
1. Inspect the cylinder head for cracks in the
exhaust ports, com bustion chambers, or external cracks
to the water cham ber.
2. Inspect the valves for burned heads, cracked
faces or dam ag ed stems.
N O TE: Excessive valve stem to bore clearance will
cause excessive oil consumption and m ay cause
valve breakage. Insufficient clearance will result in
noisy and sticky functioning o f the valve and
disturb engine smoothness.
3. M easure valve stem clearance (fig. 6A-25V) as
follows: Clam p a dial indicator on one side o f the
cylinder head rocker arm cover gasket rail, locating the
indicator so that m ovem ent o f the valve stem from side
DISCONNECT
HOSING
HERE
M A R K IV
DISCONNECT
HOSING
'
HERE
S M A L L V - 8