Honing Or Boring; Removing Piston Pin-Step; Checking Piston Pin Fit; Measuring Out O F Round Taper - Pontiac Grand Prix Service Manual

6-28
1969
PONTIAC SERVICE MANUAL
Fig. 6-53 Removing Piston Pin-Step
A
although exaggerated, illustrates area in cylinder
where normal wear occurs. Cylinder bores can be
measured by setting cylinder gauge dial at zero in the
cylinder at the point of desired measurement. Lock
dial indicator at zero before removing from cylinder,
and measure across gauge contact points with outside
micrometer, with the gauge at same zero setting when
removed from the cylinder (Fig. 6-58).
Take several measurements parallel and at right
angles to the crankshaft, between 1/2" and 4" from
Fig. 6-55 Checking Piston Pin Fit
the top of the cylinder. Subtract the smallest measure-
ment found from the largest. If this figure exceeds
.0006", a piston cannot be fitted properly, and the
cylinder must be honed. New rings and a new
oversized piston must be fitted.
Fine vertical scratches made by ring ends will not
cause excessive oil consumption, therefore, honing to
remove is unnecessary.
HONING OR BORING
If a piston in excess of .005" oversize is to be installed,
cylinder should be bored, rather than honed, to effect
a true bore.
To eliminate the possibility of honing taper into the
cylinder, full strokes of the hone should be made in
addition to checking measurement at top, middle and
bottom of bore repeatedly.
Fig. 6-54 Removing Piston Pin-Step
B Fig. 6-56 Measuring Out o f Round Taper