Crankshaft End Play Measurement

1. Place a dial indicator at the end of the crankshaft nose.
2. Gently force the crankshaft towards the front and rear of the cylinder block with a lever while monitoring the movement of the dial indicator.
3. The crankshaft endplay should not exceed specifications.
4. If the specifications are exceeded, inspect the thrust bearing thrust outer diameter and the crankshaft thrust wall for wear and/or excessive runout.

Compare the values with the specifications. Refer to Engine Mechanical Specifications.

5. Replace the thrust bearing or crankshaft as required.

Crankshaft Bearing

1. Prepare a piece of cardboard or similar, numbered 1-4 for bearing identification.

Important: Main bearing journals are numbered from the front of the engine.

2. Remove the crankshaft upper bearing halves from the cylinder block. Note the position of the thrust bearing (1) at the number 3 journal (2).
3. Place the crankshaft upper bearing halves on the cardboard in the correct positions.



4. Remove the crankshaft lower bearing halves (2) from the crankshaft bearing caps (1).
5. Place the crankshaft lower bearing halves in the correct positions on the cardboard.

Crankshaft and Main Bearing Cleaning

Clean the following components in solvent and then dry with compressed air:

Crankshaft and Main Bearing Visual Inspection

1. Perform the following visual inspections:

•	Inspect the crankshaft balancer bolt hole (1) for thread damage.

•	Inspect the crankshaft balancer mounting area (2) for damage.

•	Inspect the crankshaft sprocket pin hole (3) for damage.

•	Inspect the oil pump drive flats (4) for damage.

•	Inspect the crankshaft main journals (5) for damage.

•	Inspect the crankshaft connecting rod journals (6) for damage.

•	Inspect the crankshaft oil passages (7) for obstructions.

•	Inspect the crankshaft main bearing thrust wall surfaces (8) for damage.

•	Inspect the crankshaft counterweights (9) for damage.

•	Inspect the crankshaft reluctor ring teeth (10) for damage.

•	Inspect the crankshaft rear main oil seal surface (11) for damage.

•	Inspect the crankshaft engine flexplate mounting surface (12) for damage.

•	Inspect the crankshaft pilot hole (13) for damage.

•	Inspect the crankshaft engine flywheel bolt holes (14) for thread damage.

2. Repair or replace the crankshaft as required.

Crankshaft Main Bearing Inspection

Important: All connecting rod and main journal bearings that have been used in a running engine must be replaced. Never re-use the crankshaft or connecting rod bearings.

Important: The following bearing wear conditions should be used to diagnose engine operating conditions or root cause of a condition.

1. Inspect for fatigue indicated by craters or pockets (2). Flattened sections on the bearing halves (1) also indicate fatigue.



2. Inspect for excessive scoring or discoloration (2) on both front and back of the bearing halves (1).
3. Inspect the main bearings for dirt embedded into the bearing material.



4. Inspect for incorrect seating indicated by bright, polished sections (1).

Crankshaft Measurement

1. Using a suitable fixture (1), support the crankshaft (2).



2. Using a dial indicator (1) and magnetic base (2), rotate the crankshaft (3) carefully by hand. Measure the crankshaft main journals for runout and compare with the engine specifications.



3. Measure the crankshaft thrust wall width (1) for wear using an inside micrometer and compare with the engine specifications.
4. Measure the crankshaft thrust wall surface (2) for runout using a dial indicator, mounted to a magnetic stand and compare with the engine specifications.
5. If the crankshaft journals are damaged or worn beyond specifications, the crankshaft may be ground 0.25 mm. There is only one size of oversized main bearings available for service.



6. Inspect the crankshaft main journals (1) for under size, using an outside micrometer (2).



7. Inspect the crankpins (1) for undersize using an outside micrometer (2).
8. Compare your measurements with those listed in the engine specifications. If the crankpin journals are worn beyond the specifications, the crankshaft may be ground 0.25 mm. Only one size of oversized connecting rod bearings available for service.



9. Measure the main bearing and crankpin journals for out-of-round using the following procedure:

•	Using an outside micrometer, measure the journal at the extreme front and rear locations on the journal. Call these points A and B.

•	Measure the journal in two new locations exactly 90 degrees from the first points. Call these points C and D.

•	Subtract A from C and B from D. The differences will indicate journal out-of-round.

•	The out-of-round should not exceed 0.004 mm maximum

•	If the journals are worn beyond the specifications, the crankshaft may be ground 0.25 mm. There is only one size of oversized crankshaft and connecting rod bearings available for service

10. If the journals are worn beyond the specifications, the crankshaft may be ground 0.25 mm. There is only one size of oversized crankshaft and connecting rod bearings available for service.

•	Using an outside micrometer, measure the journal at the extreme front (A) and rear (B) of the journal parallel to the crankshaft centerline.

•	Subtract the smallest from the largest measurement. The result will be the journal taper.

•	If the main bearing journal taper exceeds 0.004 mm, replace the crankshaft

•	If the journals are worn beyond the specifications, the crankshaft may be ground 0.25 mm.

•	There is only one size of oversized crankshaft and connecting rod bearings available for service.