K 1500 Truck 4WD V8-5.7L VIN R (1997)
Connecting Rod Bearing: Testing and Inspection
Plastic Gauge Method
1. Install the crankshaft and bearings into the block.
2. Install the gauging plastic the full width of the journal.
3. Install the bearing caps and bolts.
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Tighten in sequence.
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First tighten to 27 Nm (20 ft. lbs.).
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Final tighten to 55°.
4. Remove the bearing caps and bolts. The gauging plastic may adhere to either the crankshaft journal or the bearing surface.
5. On the edge of the gauging plastic envelope there is a graduated scale. Without removing the gauging plastic, measure the compressed width at the
width point.
6. If the flattened gauging plastic tapers toward the middle or the ends, there may be a difference in clearance indicating taper, low spot or other
irregularity of the bearing or the journal.
7. Normally the crankshaft bearing journals wear evenly and are not out of round. However, if a bearing is being fitted to an out of round 0.0254 mm
(0.001 inch maximum) journal, be sure to fit to the maximum diameter of the journal. If the bearing is fitted to the minimum diameter and the
journal is excessively out of round, the interference between the bearing and the journal will result in rapid bearing failure.
8. If the bearing clearance is within specifications, the bearing is satisfactory. If the clearance is not within specifications, replace the bearing. Always
replace both the upper and lower bearings as a unit.
9. A standard or undersize bearing combination may result in the proper clearance. If the proper bearing clearance cannot be achieved using the
standard or the undersize bearings, it may be necessary to repair or replace the crankshaft.
CAUTION: Do not shim, scrape, or file bearing inserts. Do not touch the bearing surface of the insert with bare fingers. Skin oil and acids will
etch the bearing surface.
10. Remove the flattened gauging plastic.
11. Measure the remaining journals.
