OIL CATCH CAN EXPLAINED
Combustion gases "blow-by" the piston rings during the compression stroke, and enter the crankcase. They dilute the oil and promote corrosion and sludge.
Positive Crankcase Ventilation serves to cycle clean air through the crankcase, evacuating the combustion gases, by using intake manifold vacuum as a motive force.
The PCV valve vents from the engine block directly to the intake manifold.
At idle and low RPMs, vacuum in the IM draws the spring loaded PCV valve open and creates negative pressure in the crankcase. Clean, filtered air from the airbox is tapped off the turbo-charger inlet pipe by a breather hose, and drawn into the crankcase at the valve cover. This clean air sweeps through the crankcase, carrying the blow-by gas and oil-mist out through the PCV valve, where it is fed into the intake ports to be burned. The flow is one way ]] breather hose ]] crankcase ]] PCV valve ]] intake port.
Sport car tuners instal oil catch cans at both the PCV hose and the breather hose to keep contaminants out of the engine and intake.