In a piston engine, the crankcase is the housing for the crankshaft. It is part of the main cavity in the engine, separated from the cylinders by the reciprocating pistons. Crankcase vent filters used on engines separate engine oil gas from fresh air entering the air-box. This way the air filter will stay cleaner and the engine will aspirate fresher air, improving performance of the engine. Crankcase vent filters have vent tubes added to their base. Filters consist of a one-piece design with a rubber or chrome top. Filters with mounting studs can be mounted remotely, but require vent hoses and clamps. Filters mounted direct can be pressed into rubber grommets in valve covers.

Crankcase Ventilation Systems are used to vent the combustion gases from the crankcase. Crankcase ventilation systems re-circulate the gas to the intake manifold where it is delivered to the combustion chamber for combustion. Crankcase ventilation systems incorporate a positive crankcase ventilation (PCV) valve that is typically received in the opening of a rocker cover. These systems draw combustible vapors from the oil crankcase by maintaining a slight vacuum. Crankcase vapors are discharged through an oil separator directly to atmosphere and liquid oil is returned to the crankcase. These systems provide superior oil coalescence and crankcase pressure control under the most severe conditions. They will not allow crankcase emissions to be released into the atmosphere when installed in a closed system. A crankcase ventilation system uses oil separators in order to reduce oil consumption and to reduce final emission rates of the engine. These crankcase ventilation systems are optimized by measurements of the fractional particle removal efficiency, discharge curve, pressure regulation curve and leakage.

Crankshaft Gear is used directly or indirectly to drive the camshaft. It includes tube of thread locking compound, tooth front crankshaft timing belt gear and crankshaft bolt.

Crankshafts are produced with rods, bearings, inner seals, bushings, collars and o-rings. They are hand trued and welded for strength.