Crankshaft

Cleaning

Handle crankshaft (6303) with care to avoid possible fractures or damage to finish surfaces. Clean crankshaft with solvent, and blow out all oil passages with compressed air.

Clean oil seal contact surface at rear of crankshaft with solvent to remove any corrosion, sludge or varnish deposits. Excess deposits not readily removable with solvent may be removed with crocus cloth. Use crocus cloth to remove any sharp edges, burrs or other imperfections which might damage crankshaft rear oil seal (6701) during installation or cause premature seal wear. Do not use crocus cloth to the extent that seal surfaces become polished. A finely polished surface may produce poor sealing.

Inspection

Inspect main and connecting rod journals for cracks, scratches, grooves or scores.

Measure diameter of each journal in at least four places to determine out-of-round, taper or undersize condition.

Bearing failures can cause overheating of crankshaft journals and a reduction of hardness. When this occurs, the crankshaft strength may be unacceptably reduced. Whenever bluing is found on the journal or fillet area, the crankshaft must be reground by a qualified machine shop to ensure correct heat treatment during grinding.

Crankshafts must not be straightened. Even slight straightening with complete absence of cracks will endanger the high strength built into the crankshaft.

Journals, Refinishing

An induction-hardened fillet and journal crankshaft can be reground for undersized bearings.

Crankshafts should be ground at a qualified machine shop experienced in grinding induction hardened crankshafts. Crankshafts should be magnifluxed after grinding to make sure that there are no surface cracks.

Grinding Limits

Maximum allowable taper on main journals is 0.0038mm (0.00015 inch). Connecting rod journals must not be over 0.005mm (0.0002 inch) out of round.

The No. 1, 2, 3 and 4 main journal fillet radii should be 3.30mm (0.130 inch) with the crankpins (rod journals) fillet radii held at 3.68mm (0.145 inch). The No. 5 main bearing journal fillet radius should be 3.99-4.14mm (0.157-0.163 inch).

The fifth main journal controls crankshaft end thrust and provides initial location of crankshaft in relation to cylinder block. For this reason the width of the fifth journal must be 31.509-31.585mm (1.2405-1.2435 inch).