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6A1-18
1977 PONTIAC SERVICE MANUAL
Fig. 6Al-47 Measuring Valve Seat Concentricity
I
Fig. 6A1-48 Relation of Valve and Seat Angles
Intake valves are coated with a nickel-chrome alloy. Do
not grind more than .005 from valve. If removal df mord than
.005 is required to reface valve it must be replaced.
Grind valve (not more than .005) until the valve face is
true and smooth all around the valve. If this makes the valve
head thin (1/32" minimum) the valve must be replaced as the
valve will overheat and bum.
Assembly
NOTE: If valves have been serviced, it is essential that
proper valve stem heights are maintained. A suggested
method for checking installed height is using Tool J
26480 or similar gage.
1. Install camshaft removal Tool J 23591 to cylinder
head so that lifter depressing fingers are in position, but not
tightened.
2. Insert a valve in the proper port.
3. Install a new valve stem oil seal over valve guide using
Tool J 26257.
4. Install the valve spring and damper assembly and
valve cap over valve stem.
5. Compress valve spring, using Tool J 23592, and install
valve locks, making sure that locks seat properly in the valve
stem groove. Release spring and repeat procedure for
remaining valves.
NOTE: Grease may be used to hold the locks in place
while releasing the spring.
6. Check the installed height of the valve springs, using
a narrow thin scale (Fig. 6A1-50). Measure from spring seat
to the top of the valve spring. If this measurement is found
to exceed the specified height, install a valve spring seat shim
approximately 1/16" thick. Spring must not be shimmed to
give an installed height under the specified minimum.
7. Install valve lifters in their respective bore.
8. Depress lifters using Tool J 23591 as outlined in
disassembly procedures.
9. Position camshaft into cylinder head until journals are
seated in their respective bore.
Fig. 6A1-50 Measuring Valve Spring Installed Height
10. Install a new gasket, timing belt upper cover and
retainer plate and seal assembly to retain camshaft. Torque
bolts to specifications.
11. Clean, adjust, install and torque spark plugs to 15
ft. lbs.
12. Clean thermostat housing gasket surface and install
housing to head, using a new gasket.
13. Clean top of pistons and clean gasket surface of
cylinder block.
14. Install intake and exhaust manifolds.
Installation
1. Install cylinder head gasket over dowel pins with
smooth side of gasket up; then, with the aid of an assistant,
carefully guide manifolds and cylinder head assembly into
place over dowel pins and gasket.
2. Coat threads of cylinder head bolts with an approved
anti-seize compound and install finger tight; install lifting
bracket under second bolt head from front on spark plug side.
NOTE: Cylinder head bolts vary in length. Bolts on
manifold side are approximately 6 3/8" long; bolts on
spark plug side are approximately 5 5/8" long.
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