202
POWERHEAD
POWERHEAD INSPECTION
The dimensional dif ference between the two
areas is cylinder taper.
• The cylin der t aper must n ot exceed 0.002 in.
(0.05 mm).
The difference between the measurement s and
standard bore is cylin der oversize. For dimen-
sions, refer to SERVICE SPECIFICATIONS on
p. 10.
• The cylinder must not be oversized by more
than 0.003 in. (0.08 mm).
Pistons
Visually inspect pistons for sign s of abnormal
wear, scuffing, cracks, or burning.
Piston Rings
For new ring sets, place each ring separately in its
respective bore. Use a piston to square the ring in
the cylinder. Use a feele r gauge to measu re the
ring end gap.
Ring end gap should be:
• 0.011 to 0.023 in. (0.28 to 0.58 mm)
IMPORTANT: Ring end g ap increases ap proxi-
mately 0.003 in. (0. 076 mm) for e ach 0 .001 in.
(0.025 mm) incre ase in cylinder bo re diamet er.
DO NOT exceed cylinder oversize dimension.
Use a machinist’s straightedge to check for proper
ring clea rance. Position piston rings o n p iston.
Push rings into groove and hold straighted ge
against the side of the piston. Rings must be even
or just be low the surface of piston . Rings must
move freely in piston ring groove.
Bearings
Inspect center main bearings and split sleeves for
excess wear, nicks, or scratches. Replace if nec-
essary.
Inspect crankshaft rod be arings fo r excess wear,
nicks, or scratches. Replace if necessary.
1. Measurement areas DR3482
002143
31796
24381
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