PCV System: Operation: XJS

To ensure that piston blow-by gas does not escape to atmosphere, vacuum is maintained in crankcase. This is achieved by connecting the crankcase breather housing to a chamber in the left air cleaner backplate.

The chamber has 2 outlets, one of which is connected to intake manifold balance pipe, and the other to inlet side of air cleaner. The chamber outlet to the intake manifold balance pipe contains a variable orifice valve that controls part throttle crankcase ventilation.

A vacuum is maintained in the crankcase at full throttle by the vacuum on the inlet side of the air cleaner.