Cylinder Head Or Gasket-Remove And Replace - Pontiac tempest 1968 Service Manual

V-8 E N G I N E
6 - 4 9
i
w
F i g . 6 - 8 5 Testing Leak-Down Rate
4. Invert plunger with parts assembled thus far
and, after rinsing lifter body, Install body over
spring and plunger.
5. Place orifice feed plate In plunger.
6. Place lifter body on clean paper; rinse and in­
stall push rod seat and retainer ring.
7. After lifter has been assembled, place in lifter
box and close lid to preserve cleanliness.
T E S T V A L V E L I F T E R LEAK-DOWN R A T E
After all lifters have been assembled, the leak-
down rate must be checked before they are installed
in the engine. Valve lifter leak-down tester J 5790
(Fig. 6-85) is designed to test leak-down rate of
lifters to determine whether or not they are within
specified limits. As with previous service operations
concerned with lifters, cleanliness is important. The
tester cup and ram should be thoroughly cleaned,
and testing should be done in an area free of dust and
dirt. The testing procedure is described in the
following steps:
1. F i l l tester cup to approximately one inch from
top with special fluid which is available from your
lifter tester dealer.
NOTE: No other type fluid is recommended.
2. Swing weight arm up out of the way, raise
ram, and position lifter into boss in center of
tester cup.
3. Adjust ram (with weight arm clear of ram) so
that the pointer is positioned on the set line (marked
"S"). Tighten jam nut to maintain setting.
4. Operate lifter through full travel of plunger by
pumping weight arm to fill lifter with test fluid and
force out a i r . (Lifter must be completely submerged
at all times.) Continue pumping for several strokes
after definite resistance is detected.
5. Raise weight arm to allow plunger spring to
expand fully; lower arm onto ram and commence
turning crank slowly (1 revolution every 2 seconds).
Time indicator travel from lower line (first line
above set line) to line marked .125 or 1/8", while
still rotating cup with crank (Fig. 6-85). Lifter is
satisfactory if rate, is between 20 and 90 seconds.
A doubtful lifter should be tested three or four
times. Disassemble, inspect, and re-test doubtful
lifters. If leakdown still is not within specifications,
replace lifter.
6. After each lifter is tested, replace in lifter box
to insure cleanliness. Leave lifters in box until ready
for installation in cylinder block.
7. When all lifters have been tested, empty cup,
clean, and place cover over tester to maintain its
cleanliness.
CYLINDER HEAD OR GASKET-
REMOVE AND REPLACE '
REMOVE
1. Remove intake manifold, push rod cover, and
rocker arm cover.
2. Loosen all rocker arm retaining nuts and move
rocker arms off push rods.
3. Remove push rods and place in a support stand
so they can be replaced in exactly the same position
from which they were removed. See GENERAL IN­
FORMATION ON ENGINE S E R V I C E .
4. Remove exhaust pipe to manifold attaching bolts.
5. On Firebird models, remove compressor attach­
ing bolts, if equipped with A / C , and move compres­
sor to one side when removing head.
6. Remove battery ground strap and engine ground
strap on left head or engine ground strap and auto­
matic transmission oil level indicator tube bracket
on right head.
7. Remove cylinder head bolts (dowel pins will
hold head in place) and remove head with exhaust
manifold attached, using lifting hooks J 4266.
CAUTION: Extreme care should be taken when
handling or storing cylinder heads as the rocker
arm studs are hardened and may crack if struck.