Pontiac FIREBIRD 1972 Service Manual page 584

6-72 1972 PONTIAC SERVICE MANUAL
GRIND WITH FLAT STONE
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WIDTH
1
Oversize reamers are required to enlarge valve guide holes
to fit the oversize stems. When the reamer is turned
through the valve guide, it will size hole to fit valve stem
according to above limits.
Carefully ream valve guide using valve guide reamer J
5830-1 for .003" oversize stems and valve guide reamer J
6621 for .005" oversize stems (Fig. 6-12 1). For best results
when installing .005" oversize valve stem, use .003" over-
size reamer first and then ream to .005" oversize. Always
reface valve seat after reaming valve guide.
Fig. 6 - 1 2 0 Valve Seat After Grinding with Flat Stone
rotated in its seat. If blue appears all the way around
valve seat, the valve seat and valve guide are concen-
tric with one another.
3. After cleaning prussian blue from valve and seat fol-
lowing preceding check, lightly coat valve seat with
prussian blue and rotate valve in guide. If blue ap-
pears all the way around valve, the valve stem and
valve face are concentric with one another.
Both tests in steps
2
and 3 are necessary to insure
proper valve seating.
FITTING VALVE STEMS TO GUIDES
Correct valve stem clearance for valve guides is .0016" to
.0033" for intake valve and .00211' to .0038" for exhaust
valve for all except 307 engines and .0010" to .0027" for
intake valve and .0012" to .0029" for exhaust valves on the
307 engine.
Valves with oversize stems are available in .003" and .005"
larger than standard. (Valves are marked .003 or .005 with
colored ink).
The same valve stem to guide clearance applies for over-
size stems.
Fig. 6-1 2 1 Reaming Valve Guide
CYLINDER HEAD AND VALVES
ASSEMBLE
1. Install valves, valve springs, valve stem shields, valve
spring retainer cups, valve stem seals and retainer cup
locks, using suitable spring compressor. The valve
stem seals must be installed in the second groove
(from end of stem). Valve stem seal installer and
tester J 22330 can be used to install this seal (Fig.
6-103). Where necessary, install new umbrella type
seal using suitable plastic protector over end of valve
stem.
After valves have been installed, the suction cup end
of special tool J 22330 should be used to test for leaks
between the valve spring retainer cup and valve stem
seal (Fig. 6-104). The suction cup will tend to be held
to the valve spring retainer cup by suction when seal
is satisfactory. If a leak is detected, replace seal or
valve spring retainer cup as necessary. It is important
to have a positive seal between the valve spring re-
tainer cup and valve stem seal to prevent excessive
amounts of oil from being drawn down the valve stem
which will cause exhaust smoke and oil consumption.
2. Install spark plugs.
HARMONIC BALANCER
REMOVE AND REPLACE
1. Loosen generator at adjusting strap and lower pivot
bolt and remove fan belt from harmonic balancer. On
307 engine, remove ,fan and fan pulley. On cars
equipped with power steering, also remove power
steering pump belt from harmonic balancer.
2. On.all but 307 engine, position fan so wide angles will
be at top and bottom allowing access to balancer (Fig.
6- 122).
3. Remove accessory drive pulley (307 engine) and then
remove harmonic balancer attaching bolt and re-
tainer washer (all).