During inspection and overhaul of a two-stage reciprocating air compressor, the main and bottom end bearing shells are found to be heavily scored with parts of the overlay and bearing metal breaking away. The crankshaft pins have only very light surface scratches.
What is the probable cause of such damage and which action to be taken to remedy the problem?
The most probable cause of the damage is a prolonged operation of the compressor with water-contaminated oil.
Replace the bearing shells with new spares after cleaning out the crankcase and refilling with clean oil.
