Positive Crankcase Ventilation: Description and Operation

Throttle Chamber:

PURPOSE
The Positive Crankcase Ventilation System prevents air pollution caused by blow-by gasses being vented to the atmosphere.

LOCATION
Screwed into the intake plenum.

OPERATION
The system consists of a sealed oil filler cap, rocker cover with fresh air inlet, connecting hoses, PCV valve and air intake duct. At part throttle, blow-by gas is drawn by strong vacuum into the intake manifold through the crankcase connecting hose and PCV valve. Fresh air is introduced into the crankcase through rocker cover connecting hose. During wide open throttle (low manifold vacuum), part of the blow-by gas flows into the air intake duct through the connecting hose and then into the engine through the throttle valve.