Pontiac FIREBIRD 1972 Service Manual page 582

6-70 1972 PONTIAC SERVICE MANUAL
SCREWED IN STUDS
REMOVE AND REPLACE
1. Remove rocker arm cover.
2. Remove rocker arm and nut.
3. Using a deep well socket, remove rocker stud.
4.
Install new stud and tighten to 50 lb. ft.
5. Install rocker arm and tighten nut to 20 lb. ft.
6. Install rocker arm cover using new gasket.
CYLINDER HEAD AND VALVES
DISASSEMBLE
1. Remove valve spring retainer cup locks (keepers),
valve rotators (exhaust valves of 307), valve stem oil
seals, valve spring retainer cups, valve stem shields,
valve springs, and valves, using valve spring compres-
sor J 8062. Valve stem oil seals must be discarded and
replaced with new seals any time they are removed.
areas of cylinder head. If a scraper or wire brush
is used for cleaning, use care to prevent damage
to valve seats (by staying clear of seat area with
tool).
b. Clean cylinder head thoroughly, using suitable
cleaning equipment.
4. Clean valve guides thoroughly, using valve guide
cleaner
J
8101 (Fig. 6-1 16).
5. Visually inspect valve guides for evidence of wear,
especially the end toward the spring seat. If a guide
is scored or galled, install valve with proper oversize
stem according to procedure.
6. Clean valve springs and valve rotators (307 engine)
and inspect for damage.
7. Clean push rods and thoroughly clean out oil passage
through center of rod. Inspect to see that the rod is
straight.
8. Clean rocker arms and rocker arm balls, and visually
inspect for evidence of wear.
9. Clean spark plugs as outlined in ENGINE ELEC-
TRICAL SECTION.
10. Clean and inspect valve lifters.
2. Place valves in valve and valve train holding stand.
CHECKING ROTATORS (307 ENGINE)
CYLINDER HEAD AND VALVES
CLEAN AND INSPECT
Efficient engine performance depends to a great degree
upon the condition of engine valves. Close inspection of
intake valves is especially important as excessive clearance
of valve stems in guides will permit oil to be pulled into
the combustion chamber, causing fouled spark plugs and
clogged piston rings. Oil deposited on valve heads will
carbonize and bum, causing valves to leak with resultant
loss of engine power. Therefore, valves must operate prop-
erly and if inspection discloses any malfunction of valves,
the trouble must be corrected to avoid future damage to
valves or related engine parts.
1. Inspect valves and seats to determine condition
before cleaning. Also examine water passage plugs
for evidence of leakage.
2. Clean valves thoroughly to remove deposits from
head and stem.
3. Clean and inspect cylinder head as follows:
a. Clean carbon deposits from combustion cham-
bers and all sludge or foreign matter from other
The valve rotators used on exhaust valves of the 307 en-
gine cannot be disassembled and require replacement only
when they fail to rotate the valve.
Rotator action can be checked by applying a daub of paint
across the top of the body and down the collar (Fig.
Fig. 6-1 16 Cleaning Valve Guide