Pontiac FIREBIRD 1972 Service Manual page 538

6-26 1972 PONTIAC SERVICE MANUAL
5. With lifter on base circle of camshaft tighten rocker
arm nut until all valve train play is removed. Tighten
nut one additional turn.
6. Install spark plug.
7. Install rocker arm cover.
-
CYLINDER HEAD AND VALVES
The condition of the cylinder head and valve mechanism
significantly determines the power, performance and
economy of a valve-in-head engine. Extreme care should
be exercised when conditioning the cylinder head and
valves to maintain correct valve .stem-to-guide clearance,
correctly ground valves, valve seats of correct width and
correct valve adjustment.
DISASSEMBLE
1. Remove the cylinder head and gasket as previously
described. Place cylinder head on two blocks of wood
to prevent damage.
2. Remove rocker arm nuts, ball seats and rocker arms.
3. Using tool 5-22891, compress the valve springs and
remove valve locks. Remove spring caps, spring
seats, oil seals, springs and spring dampers (Fig. 6-
3 5).
4. Remove valves from bottom of cylinder head and
place them in a rack in their proper sequence so they
can be assembled in their original positions.
5. Remove water outlet and thermostat, then remove
thermostat housing.
CLEAN AND INSPECT
Clean all carbon from combustion chambers and
valve ports.
Thoroughly clean the valve guides using tool 5-8101
(Fig. 6-36).
Clean all carbon and sludge from push rods and
rocker arms.
Clean valve stems and heads on a buffing wheel.
Clean carbon deposits from head gasket mating sur-
faces.
Wash all parts in cleaning solvent and dry them
thoroughly.
Inspect the cylinder head for cracks in the exhaust
ports, combustion chambers, or external cracks in the
water chamber.
Fig. 6-35 Upper Valve Train Parts Fig. 6 - 3 6 Cleaning Valve Guide Bore