BadgerType
Resident ***hole
What is it:
In an engine, there are two areas of air pockets in which the air is not directly related to combustion. Within these two areas, oil and air are separated from the combustion chambers and coolant jackets for the purpose of lubrication of the engine. The upper air and oil pocket is constrained by the valve cover at the top, and the valve seals at the lower end. The bottom air and oil pocket is constrained by the piston rings at the top and the oil pan in the bottom.
In a perfect world, these two lubrication areas would not pressurize. However, in real life compression leaks by valve seals and piston rings in what is called blow-by. Blow by introduces pressure into the two pockets of air and oil (the head and the crankcase). In addition, heat caused as a byproduct of combustion causes air molecules to expand which also causes the pressure to increase in these lubrication areas. If no ventilation system was employed to release this pressure, it would find the point of least resistance to escape, which could be oil seals...or worse.
To relieve this pressure, a system called Positive Crankcase Ventilation (PCV for short) is used. It is a closed system that takes the pressurized air and oil vapor from these two lubrication areas and introduces it back into the combustion chamber, by way of vacuum caused by the intake charge.
What good is it for our cars:
On a stock or slightly modified car, there is little point of this. For me, its partially used to prevent detonation when I use nitrous. This is also gonna be needed when I go turbo and is a cheaper version than the $90 ones. Plus I would like to keep the intake manifold clean as possible, lol.
