3-41. CRANKSHAFT BEARINGS (Cont).
Before installing new replacement bearings, it is very important to thoroughly inspect the crankshaft journals.
Very often, after prolonged engine operation, a ridge is formed on the crankshaft journals in line with the journal
oil holes. If this ridge is not removed before the new bearings are installed, then, during engine operation,
localized high unit pressures in the center area of the bearing shell will cause pitting of the bearing surface.
Also, damaged bearings may cause bending fatigue and resultant cracks in the crankshaft. Refer to paragraph
3-42 under Crankshaft Inspection for removal of ridges and inspection of the crankshaft.
Do not replace one main bearing shell alone. If one bearing shell requires replacement, install both new upper
and lower bearing shells. Also, if a new or reground crankshaft is to be used, install all new bearing shells.
If the washers
are scored or
ly or the
play is exces-
sive, they must
on the thrust
If, after dres-
sing or re-
washers do not
hold the crank-
shaft end play
within the spec-
it may be nec-
essary to in-