Hydraulic Valve Lifter; Testing Leak-Down Rate - Pontiac Grand Prix Service Manual

6-50 1969 PONTIAC SERVICE MANUAL
force out air. (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 .I25 or 1/8", while still rotating
cup with crank (Fig. 6-86). 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
leak-down still is not within specifications, replace
lifter.
6. After each lifter is tested, replace in lifter box to
insure cleaniness. 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 cleaniness.
CYI-INDER HEAD OR GASKET
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 INFOR-
MATION ON ENGINE SERVICE.
4. Remove exhaust pipe to manifold attaching bolts.
5. On Firebird models, remove compressor attaching
bolts, if equipped with A/C, and move compressor to
one side when removing head.
BALL CHECK
VALVE RETAINER
BODY
VALVE SPRING VALVE
ROCKER FEED
METERING VALVE
REiggER
6. Remove battery ground strap and engine ground
strap on left head or engine ground strap and
automatic 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 i f struck.
NOTE: If left head is being removed, it will be necessary
to raise head off dowel pins, move it forward and
maneuver the head in order to clear the power steering
and power brake equipment i f car is so equipped.
NOTE: On Firebird models, when removing the right
head on V-8's equipped with AIC, it is necessary to
remove the right insulator to pame bolt and raise engine
approximately 2" to gain access to the right rear valve
cover bolt and right rear cylinder head bolt. Care must
be taken to avoid the fan cmtacting the fan shroud.
9. Remove cylinder head gasket.
REPLACE
NOTE: Right and left cylinder heads are the same. New
heads are complete with rocker arm studs (exc. heads
with screwed in stud) and allplugs.
When installing new head, transfer all serviceable
parts to new head, using new seals on intake and
exhaust valve stems, and new exhaust manifold gasket.
Fig. 6-85 Hydraulic Valve Lifter
-
Exploded View
Fig. 6-86 Testing Leak-Down Rate