Check Crankshaft Bearing Clearance (With Micrometer Gauge Internal Measuring Device)

Install and tighten the crankshaft bearing cap tie plate and the crankshaft bearings as shown above.
NOTE: The bolts can be reused for checking the crankshaft bearing play.
Measure the crankshaft bearing diameter at 3 points.

Fig 1: Crankshaft Bearing Diameter Measuring Points
Courtesy of GENERAL MOTORS COMPANY

Measure in areas as shown (1) with an internal measuring device.

Calculate the average crankshaft bearing diameter.

Formula: 1. result + 2. result + 3. result / 3.
Measure the crankshaft bearing journal diameter at 2 points between (1) and (3) and between (2) and (4) with the micrometer gauge.

Fig 2: Connecting Rod Journal Diameter Points
Courtesy of GENERAL MOTORS COMPANY
Calculate the average crankshaft bearing journal diameter.
Formula: 1. result + 2. result / 2.
Determine the crankshaft bearing play.
Calculation formula: average crankshaft bearing diameter minus average crankshaft bearing journal diameter.
The crankshaft bearing play should be 0.007-0.031 mm (0.00028-0.00122 in).