Measuring the Cylinder for Oversize

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Fig 1: Measuring Bore Gauge With Micrometer

Courtesy of GENERAL MOTORS COMPANY

Adjust the micrometer to a dimension slightly smaller than the bore size. Refer to Engine Mechanical Specifications (L83)Engine Mechanical Specifications (L86) .
Insert the J 8087 gauge into the micrometer and zero the bore gauge dial.

Fig 2: Measuring Cylinder Bore

Courtesy of GENERAL MOTORS COMPANY

Use the J 8087 gauge and measure the cylinder bore for oversize.
Slide the bore gauge up and down throughout the length of the cylinder bore. Measure the bore, both parallel and perpendicular to the centerline of the crankshaft, at the top, center, and bottom of the bore. A cylinder bore that exceeds the maximum diameter must be serviced with an oversized piston. Refer to Engine Mechanical Specifications (L83)Engine Mechanical Specifications (L86) .