Inspection and Reconditioning (Rev 1/97)
45
8. Measure the main bearing bores both vertically and
horizontally. If the main bearing bores are more than
.001 in. (0.25 mm) out of round, the block must be
align bored.
Measuring Main Bearing Bore
9. Check the main bearing bore alignment with a straight
edge and a .0015 in. (0.381 mm) feeler gauge. Lay the
straight edge in main bearing bores of the block and
place the feeler gauge between the straight edge and
each main bearing bore. There should be some drag on
the feeler gauge at each main bearing bore. If there is
no drag on the feeler gauge at any main bearing bore,
the block must be align bored.
Checking Main Bearing Bore Alignment
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10. Measure each tappet bore in the block. If any of the tap-
pet bores are larger than the wear limit (refer to Specifi-
cations) the block must be replaced. Normally very
little, if any, wear occurs in the tappet bores. Small
scratches or nicks should be cleaned up with a brake
cylinder hone. The tappet bores should also be lightly
honed after the block has been boiled out.
Measuring Tappet Bore
11. Check or replace all of the core plugs.
Crankshaft
1. Check the crankshaft for cracks and check the main
journals, rod journals, and the oil seal surface for exces-
sive wear or damage. Check to see that the oil passages
are not clogged or dirty.
2. Measure the main journals. If any of the main journals
are smaller than the wear limits (refer to Specifica-
tions), or tapered or out of round more than .0010 in.
(0.025 mm), the main journals must be ground under-
size.
Only the .010 in. (0.25 mm) undersize main bearings
are available. Refer to Specifications for the suggested
outside diameter of undersized main journals.
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