Pontiac Fiero 1988 Service Manual page 296

GENERAL ENGINE MECHANICAL 6A-19
Important
Valve lifters may be cleaned to eliminate
sticking due to sludge and varnish. They
must be reinstalled in their original position
on the engine. Valve lifter components must
be reassembled into the lifter from which
they were removed.
There are two types of valve lifters: a flat
tappet hydraulic type (Figure 43) for most
engines and a roller tappet type (Figure 44).
They function in a similar manner.
If the camshaft was replaced, the lifters
must also be replaced (except roller lifters).
1 - LIFTER BODY
2 - PLUNGER SPRING
3 - BALL CHECK RETAINER
4 - BALL CHECK SPRING
5 - BALL CHECK
6 - PLUNGER
7 - OIL METERING VALVE
8 - PUSH ROD SEAT
9- RETAINER RING
G20039 6A
Figure 43 Valve Lifter - Flat Tappet
1 —ROLLER
2 - LIFTER BODY
3 - PLUNGER SPRING
4 - BALL CHECK RETAINER
5 - BALL CHECK SPRING
6 - BALL CHECK
7 - PLUNGER
8 - OIL METERING VALVE
9 - PUSH ROD SEAT
10—RETAINER RING
G20040-6A
Figure 44 Valve Lifter - Roller Tappet
Disassemble
• Valve lifter
Remove or Disconnect
1. Push rod seat retainer. Hold plunger down with
a push rod and remove retainer with a small
screwdriver.
2. Push rod seat
3. Metering valve
4. Plunger. If the plunger is stuck, turn the lifter
body upside down and tap on a flat surface. If the
plunger cannot be moved, soak in carburetor
cleaning fluid.
C A U T I O N : D o n o t b r e a t h e f u m e s a n d
a v o i d s k i n c o n t a c t w i t h c a r b u r e t o r
c l e a n i n g f l u i d .
5. Ball check valve assembly. Remove with a small
screwdriver.
6. Plunger spring
Clean
2.
3.
4.
5.
Sludge
Varnish
jW| Inspect
Lifter body for:
Wear
Scuffing. Also inspect the bore in the
cylinder block.
Flat spot on the bottom. If the bottom is
worn flat, or grooved, replace the lifter.
Also inspect the camshaft lobe.
Roller (if equipped) for:
Freedom of movement. Replace the lifter if
it binds or roughness can be felt.
Excessive looseness in the roller bearings.
Replace if necessary.
Flat spots. Replace the lifter, if worn.
Pitting. Replace the lifter if pitted.
Push rod seat. If worn, inspect the push rod.
Replace if worn.
Uj Important
• Do not attempt reconditioning by taking
parts from other unserviceable lifters.
• Cleanliness is very important. Lint or dirt
will cause the lifter to fail.
Assemble
Check ball on small hole in the bottom of the
plunger.
Check ball spring. Insert in ball retainer.
Ball retainer. Place ball retainer and spring over
the check ball and press retainer into position in
the plunger with a small screwdriver.
Plunger spring, over the ball retainer.
Lifter body over the spring and plunger. Line up
oil holes in the lifter body and the plunger.
Fill the lifter with SAE 10 engine oil
With a 3mm (1/8") drift pin push down the
plunger until the oil holes in the lifter body
and the plunger are aligned.
Insert a 1.5mm (1/16") pin through the oil