Crankcase in Engines

The crankcase is the container which enclosed the crankshaft.  The crankshaft is mounted on the crankcase.  Crankcases are usually made of cast iron. The pistons and the connecting rods are mounted above the crankcase.  The crankcase protects the lower parts of the pistons from foreign particles. 

It is the largest enclosure in the engine.  In wet sump engines, the oil sump is located at the bottom of the crankcase.