Hummer H1 Service Manual page 100

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Figure 2-106: Measuring Cylinder Taper and Wear
with Bore Gauge
AXIS "A"
AXIS "B"
05745159
BORE GAUGE
J – 8087
CYLINDER BORE
Figure 2-107: Cylinder Bore Measuring Points
Measure piston skirt diameter at the centerline of the piston pin
but at a right angle (opposite) to the pin. Refer to the "Service
Piston and Cylinder Bore Specifications" data at the end of this
section for dimensions.
Remove the piston rings, insert the piston in the bore, and
check piston-to-bore clearance with a feeler gauge. Clearance
should not exceed 0.004 in. (0.120 mm) on cylinders 1 through
6, and 0.005 in. (0.133 mm) on cylinders 7 and 8.
• Replace the piston if the skirt is severely scored,
collapsed, or worn below specified limits.
• Reuse the piston if in good condition and wear is
minimal. However, if the cylinder bore is worn and
requires reboring, the piston must be replaced, even
if it's in good condition.
• Replace the piston if the bore is OK but piston-to-
bore clearance is greater than specified.
Remove all the expansion/freeze plugs with a punch and ham-
mer. Coat the edges of replacement plugs with Permatex #2, or
a high temp RTV sealer. Seat the new plugs in the block with a
suitable size socket and hammer. Be very sure each plug is
firmly seated. Replace any plug that becomes distorted during
installation; do not salvage it.
Engine 2-63