Pontiac tempest 1968 Service Manual page 270

V-8 E N G I N E 6-53
GRIND WITH FLAT STONE
SEAT
WIDTH
F i g . 6-91 V a l v e Seat After Grinding With Flat Stone
flat stone (Fig
e
6-91), This is the only method that
should be used to narrow the seat.
NOTE: Lapping of valve seats is not required or
recommended.
2. Check concentricity of valve seat and valve
guide. Concentricity of valve seat and valve guide
can be checked by using a suitable dial indicator or
prussian blue. When using a dial indicator, total
runout should not exceed .002".
When prussian blue Is used, a light coat should be
applied to the face of the valve only and the valve
rotated in its seat. If blue appears all the way
around valve seat, the valve seat and valve guide
are concentric with one another.
3. Check concentricity of valve stem and face of
valve. After cleaning prussian blue from valve and
seat from preceding check, lightly coat valve seat
with prussian blue and rotate valve in guide. If blue
appears all the way around valve, the valve stem
and valve face are concentric with one another.
NOTE: Both tests in steps 2 and 3 are necessary
to insure proper valve seating.
REAMER
F i g . 6-92 Reaming V a l v e G u i d e
FITTING V A L V E STEMS TO GUIDES
Correct valve stem clearance for valve guides is
.0016" to .0033" for intake valve and .0021" to .0038"
for exhaust valve.
Valves with oversize stems are available in .001",
.003" and .005" larger than standard. The same valve
stem to guide clearance applied for oversize stems.
Oversize reamers are required to enlarge valve
guide holes to fit the oversize stems. When the
reamer is turned through 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.
6-92). For best results when installing .005" over­
size valve stem, use .003" oversize reamer first
and then ream to .005" oversize. Always reface
valve seat after reaming valve guide.
NOTE: Valves are marked .001, .003 or .005 with
colored ink.
CYLINDER HEAD AND V A L V E S - A S S E M B L E
1. Install valves, valve springs, valve stem shields
valve spring retainer cups, valve stem seals and re­
tainer 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. 6-79). 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. 6-80). 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 retainer 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-TIMING CHAIN COVER
AND GASKET-TIMING CHAIN AND SPROCKETS-
OIL SEAL-FUEL PUMP ECCENTRIC
HARMONIC B A L A N C E R -
REMOVE AND R E P L A C E
1. Loosen generator at adjusting strap and lower
pivot bolt and remove fan belt from harmonic bal­
ancer. On cars equipped with power steering, also