Pontiac FIREBIRD 1972 Service Manual page 534

6-22 1972 PONTIAC SERVICE MANUAL
3. After varnish has dissolved or has been sufficiently
softened to permit removal by wiping, suspend tray
above solvent, utilizing hooks on tray handles. Allow
tray and parts to drain for a brief period.
4. Rinse tray of parts in kerosene chamber to cut solvent
and to avoid injury to hands (from solvent).
5. Remove tank cover and place tray of parts on cover
in front of tank. A shop towel under tray and clean
paper on remainder of cover will ensure cleanliness.
6. Working on one lifter at a time and using clean,
lint-free cloths, thoroughly wipe off lifter parts. Clean
plunger and external and internal surfaces of body
with a hard wiping action. A bristle brush may be
used to clean internal surface of lifter body.
CAUTION: Do not use wire brush or sand pa-
per, as these may damage machined surfaces.
Absolute cleanliness can be assured if each
lifter is inspected and assembled after cleaning
but before proceeding to the next lifter.
7. Inspect lifter body. Both inner and outer surfaces of
lifter body should be inspected for scoring. Lifter
assembly should be replaced if body is roughly
scored, grooved, or galled. Inspect cam contact sur-
face on lower end of lifter body. Replace lifter assem-
bly if this surface is excessively worn, galled or
otherwise damaged.
8. Inspect lifter plunger. Using a magnifying glass, in-
spect the check ball seat for defects. Inspect outer
surface of plunger for scratches or scores. Small score
marks with a rough, satiny finish will cause the
plunger to seize when hot but operate normally when
cool. Defects in check ball seat or scores or scratches
on outer surface of plunger which may be felt with a
fingernail are causes for replacing the lifter assembly.
This rule does not apply to the slight edge which may
sometimes be present where the lower end of plunger
extends below the ground inner surface of the body.
This edge is not detrimental unless it is sharp or
burred.
A blackened appearance is not a defective condition.
Sometimes the discoloration serves to highlight slight
grinder chatter marks and give the outer surface of
the plunger a ridged or fluted appearance. This con-
dition will not cause improper operation, therefore, it
may be disregarded.
9. Inspect push rod seat for roughness and to ensure
that hole in center is open.
10. Inspect valve lifter ball. Carefully examine ball for
nicks, embedded material or other defects which
would prevent proper seating. Such defects may
cause intermittently noisy lifter operation. Also in-
spect plunger face of ball retainer for excessive wear.
ASSEMBLE
All parts must be absolutely clean when assembling a
hydraulic lifter. Since lint and dust may adhere to parts,
they should not be blown o f f with air or wiped with cloths.
A llparts should be rinsed in clean kerosene and assembled
without drying. A small container with clean kerosene
(separate from cleaning tank) should be used for each set
of lifters being overhauled.
Figure 6-26 shows the relative position of component
parts of valve lifters. The recommended procedure for
assembly is given in the following steps.
1. Rinse plunger spring and ball retainer and position
retainer in spring.
2. Rinse lifter ball and place it and the small spring in
retainer.
3. Rinse plunger and place on retainer so that seat on
plunger mates with ball.
4. Invert plunger with parts assembled thus far and
after rinsing lifter body, install body over spring and
plunger.
5. Place lifter body on clean paper, rinse and install
push rod seat and retainer ring.
6. After lifter has been assembled, place in lifter box and
close lid to preserve cleanliness.
TEST LEAK-DOWN RATE
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 5-5790 (Fig. 6-27) is designed
to test leak-down rate of lifters to determine whether or
BODY
BALL CHE
VALVE RETP
PLUNGER
SPRING
BALL CHECK / B A L L
CHECK
L e j *
' VALVE SPRING VALVE
1 '
ROD
AT
ROCKER FEED / R E T A I N E R
-\J'
METERING VALVE
Fig. 6-26 Hydraulic Valve Lifter
-
Exploded View