Cylinder Head Gasket; Cylinder Head Torque Sequence; Measuring Valve Stem Height - Pontiac TRANS AM 1977 Service Manual

3 5 0 AND 4 0 3 ENGINE 6A4-13
STRI PE OF CONTRAST1 NG
COLOR - TOWARDS CYLINDER
HEAD
350 C. I. D.
3696
Fig. 6A4-25 Cylinder Head Gasket
Fig. 6A4-26 Cylinder Head Torque Sequence
Fig. 6A4-27 Relation of Valve and Seat Angles
Measuring Valve Stem Height
Whenever a new valve is installed, or after grinding
valves, it will be necessary to measure valve stem height as
follows:
Install Gauge BT-6428 as shown in Fig. 6A4-28.
Fig. 6A4-28 Measuring Valve Stem Height
There should be at least .015" clearance on all valves
between gauge surface and end of valve stem. (Valve stem can
be gauged with or without the valve rotator on the valve). If
clearance is less than .015", remove valve and grind tip of
valve stems as required on a valve refacing machine using the
"Vee" block attachment to insure a smooth 90" end. Also be
certain to break sharp edge on ground valve tip. Observe an
original valve to determine chamfer.
After all valve keys have been installed on valves, tap
each valve stem end with a hammer to seat valve rotators and
keys. Using Gauge BT-6428 as shown in Figs. 6A4-28 and
6A4-29, re-gauge all valves between valve stem and gauge
(.015" minimum) and valve rotator and gauge. (.030M
minimum). If any valve stem end is less than .005" above
rotator, the valve is too short and a new valve must be
installed.
EXAMPLE:
Valve Rotator to Gauge Clearance
..............................
38"
Minus Valve Stem to Gauge Clearance
...........
.035" -.003"
This is less than .005" and a new valve should be
installed.
NOTE: There must be a minimum of .030" clearance
between valve rotator and gauge. Failure to maintain
this clearance will cause rocker arm and valve rotator
interference.
VALVE GUIDE BORES
As previously stated, if the valve guide bores are worn
excessively, they can be reamed oversize. The following
reamers are available:
....................
BT-6414- 1 .003" Oversize Valve Guide Reamer
....................
BT-6414-4
.005" Oversize Valve Guide Reamer
BT-6414-3
..................
.0 13 " Oversize Valve Guide Reamer
If a standard or .003" O.S. valve guide bore is being
reamed, use the .003' oversize reamer. For the .005" oversize
valve guide bore, use the ,005" oversize reamer, use the ,013"