Grand Cherokee 2WD L6-4.0L VIN S (1997)
6. Remove the bearing cap. Determine the amount of clearance by measuring the width of the compressed Plastigage with the scale on the Plastigage
envelope. Refer to Specifications for the proper clearance.
7. Plastigage should indicate the same clearance across the entire width of the insert. If clearance varies, it may indicate a tapered journal or foreign
material trapped behind the insert.
8. If the specified clearance is indicated and there are no abnormal wear patterns, replacement of the bearing inserts is not necessary. Remove the
Plastigage from the crankshaft journal and bearing insert. Install crankshaft main bearings.
9. If the clearance exceeds specification, install a pair of 0.025 mm (0.001 inch) undersize bearing inserts and measure the clearance as described in
the previous steps.
10. The clearance indicate with the 0.025 mm (0.001 inch) undersize insert pair installed will determine if this insert size or some other combination
will provide the specified clearance.
FOR EXAMPLE: If the clearance was 0.762 mm (0.003 inch) originally, a pair of 0.0254 mm (0.001 inch) undersize inserts would reduce the
clearance by 0.0254 mm (0.001 inch). The clearance would then be 0.0508 mm (0.002 inch) and within the specification. A 0.051 mm (0.002
inch) undersize bearing insert and a 0.0254 mm (0.001 inch) undersize insert would reduce the original clearance an additional 0.0127 mm
(0.0005 inch). The clearance would then be 0.0381 mm (0.0015 inch).
CAUTION:
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Never use a pair of inserts that differ more than one bearing size as a pair.
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DO NOT use a standard size upper insert and a 0.051 mm (0.002 inch) undersize lower insert. If the clearance exceeds specification using a pair
of 0.051 mm (0.002 inch) undersize bearing inserts, measure crankshaft journal diameter with a micrometer. If the journal diameter is correct, the
crankshaft bore in the cylinder block may be misaligned, which requires cylinder block replacement or machining to true bore.
11. Replace the crankshaft or grind to accept the appropriate undersize bearing inserts if:
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Journal diameters 1 through 6 are less than 63.4517 mm (2.4981 inches)
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Journal 7 diameter is less than 63.4365 mm (2.4975 inches).
12. Once the proper clearances have been obtained, install crankshaft main bearings.
