Two technicians are discussing undersized bearings. Technician A says a 0.001 in. or 0.002 in. bearing can be used on a stock crankshaft journal if the oil clearance [difference between the bearing diameter and the journal diameter] is slightly excessive and the journal is not excessively tapered or out of round. Technician B says 0.010 in., 0.020 in., and 0.030 in. undersized bearings are only used when the crankshaft journals have been reground. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Question

Quizplus · Accepted Answer

Technician A is correct because using slightly undersized bearings can compensate for excessive oil clearance without the need for crankshaft regrinding, provided the journal's condition is within acceptable limits. Technician B is also correct because bearings that are 0.010 in., 0.020 in., and 0.030 in. undersized are typically used when the crankshaft journals have been reground to restore proper clearances and journal surface conditions.

Two Technicians Are Discussing Undersized Bearings