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6A4-14
1977 PONTIAC SERVICE MANUAL
Fig.
6A4-29
Measuring Rotor Height
eamer for the .010" or .013" O.S. valve guide bore. If too
rl
large a reamer is used and the spiraling is removed, it is
problable that the valve will not receive the proper
lubrication.
Occasionally a valve guide bore will be oversize as
manufactured. These are marked on the inboard side of the
cylinder heads on the machined surface just above the intake
manifold surface. (Fig. 6A4-30) These markings are visible
without removing any parts other than the air cleaner
assembly. Before removing the cylinder heads to perform
service to either the valve or valve guide bores, the cylinder
heads should be inspected to determine if these markings are
present. If no markings are present, the guide bores are
standard. If oversize markings are present, any valve
replacement will require an oversize valve. If the oversize
marking is present, only that particular bore would be
oversize, not all bores in that cylinder head. Service valves
are available in five differenct stem diameters: Standard,
.003" oversize, .005" oversize, .010" oversize, and .013"
oversize.
REAMING PROCEDURE
Before attempting to ream the valve guide bores they
should be cleaned using Tool BT-6415 as shown in Fig. 6A4-
31.
The procedure to ream valve guide bores using Tool BT-
6414 is shown in Fig. 6A4-32. Use care to hold reamer
straight in valve guide bore.
CRANKSHAFT PULLEY
Removal
1. Remove belts.
2. Hoist Car.
3. Remove four pulley bolts and pulley.
Installation
1. Install pulley, and four bolts. Torque to 10 ft. lbs.
2. Install belt(s). Adjust belts using Tool BT-6002-3.
I
iTAbDAl?D
-
NO MARKING
Fig.
6A4-30
Valve Guide Bore Markings
Fig.
6A4-31
Cleaning Valve Guide Bores
BT-6414- 1
=
,003"
0 5.
BT-6414-4
=
.
W5"
0. 5.
VALVE
GUlDC
BT-6414-3
=
,013" 0. 5
Fig.
6A4-32
Reaming Valve Guide Bores
BALANCER
Removal
1. Remove belt and crankshaft pulley.
2. Remove balancer hub bolt and washer.
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