Crankshaft And Crankshaft Bearing

Clean crankshaft completely and check for cracks by means of red lead check etc., and replace if defective.
Measure the crankshaft bend, and correct or replace if it exceeds the limit.
CAUTION: If a suitable V-block is not available, install #1 and #5 crankshaft bearing on cylinder block, position crankshaft on these bearings and measure crankshaft bend using a dial gauge.
1. Crankshaft bend limit: 0.035 mm (0.0014 in)
Fig 1: Measuring Crankshaft Bend
Courtesy of SUBARU OF AMERICA, INC.
Inspect the crank journal and crank pin for wear. If they are not within the specifications, replace bearing with a suitable (undersize) one, and replace or recondition crankshaft as necessary. When grinding crank journal or crank pin, finish them to the specified dimensions according to the undersize bearing to be used.
Crank pin and crank journal:
1. Out-of-roundness: 0.020 mm (0.0008 in) or less
2. Taper limit: 0.07 mm (0.0028 in) Grinding
3. Grinding limit 0.250 mm (0.0098 in)
Fig 2: Inspecting Crank Journal & Crank Pin For Wear
Courtesy of SUBARU OF AMERICA, INC.

Fig 3: Crank Journal & Pin Specifications Chart
Courtesy of SUBARU OF AMERICA, INC.
Measure the thrust clearance of crankshaft at center bearing. If the clearance exceeds the limit, replace bearing.
Crankshaft thrust clearance:
1. Standard: 0.030 - 0.115 mm (0.0012 - 0.0045 in)
2. Limit: 0.25 mm (0.0098 in)
Fig 4: Measuring Thrust Clearance Of Crankshaft At Center Bearing
Courtesy of SUBARU OF AMERICA, INC.
Inspect individual crankshaft bearings for signs of flaking, seizure, melting, and wear.
Measure the oil clearance on each crankshaft bearing by means of plastigauge. If the measurement is not within the specification, replace defective bearing with an undersize one, and replace or recondition crankshaft as necessary.

Fig 5: Crankshaft Oil Clearance Specification Chart
Courtesy of SUBARU OF AMERICA, INC.