Generac 86640 - Manual (Page 42)

Inspection (Continued)
a. DO NOT turn the crankshaft or connecting rod when
Plastigage^ is being inserted.
b. When bearing clearance exceeds the specified limit,
check that the correct bearing has been installed. If exces­
sive clearance still exists, use a thicker main bearing or an
undersize bearing to obtain correct clearance.
BEARING CLEARANCE
Main Bearing= 0.0012-0.0020 Inch (0.03-0.05mm)
Limit = 0.0030 inch (0.075mm)
Connecting
Rod Bearing= 0.0008-0.0024 Inch (0.02-0.06mm)
Limit = 0.0047 inch (0.12mm)
Figure 55. Checking Ring Gap
5. Inspect crankshaft journals for scoring, bias, wear or
cracks. Minor defects can be corrected using fine crocus
cloth. Use a micrometer to check journals for taper and
out-of-round. See Figure 57.
Out-of-Round (X-Y) = 0.0004 Inch (0.01mm)
Taper (A-B) = Less than 0.0008 inch (0.02mm)
6. When regrinding crankpin journal, measure the “L° dimen­
sion in the fillet roll (Figure 58). The measured value must
exceed the specified limit. If measurements are within the
specified limit, DO NOT regrind.
NOTE: DO NOT grind off the fillet roll. Refer to applicable
SPECIFICATIONS chart for regrlndlng crankshaft and
available service parts.
7. Check crankshaft runout. “T.I.R." stands for "Total
Indicator Reading".
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