Rocker cover vents, oil catch cans and engine temperatures.

[poison]

It's not really power mods but there is no "Engine" forum so I'll stick it here.....

This is a fundamental question I should know the answer to but I'm not entirely sure…..

On the rocker cover there are two breather pipes, one connects to the inlet manifold and is fitted with what looks like a one way valve. So I assume this sucks all the fumes into the engine and burns them up. The other pipe seems to go to a black canister, I assume this is to do with emission control. So what does it do? Any benefit in removing it? Just cosmetics?

I have seen people replace the canister and pipe with a dinky little K&N filter mounted directly onto the rocker cover. What is the point of this?

Also what is the point of an "oil catch can?" where does this go? Does it go between the inlet manifold and the rocker cover so that the dirty crap doesn't get fed back into the engine?

I am about to do some engine temperature tests (referenced to ambient) with and without the engine splash guard so will be able to tell for sure if there is, or isn't any advantage. Will post my results…..

Gazza

[SLYDIT]

it is best to keep your crankcase ventilation as the factory intended. Adding little air filters etc reduces the effectiveness of the block vapour scavenging and also alters your Air flow meter readings depending on how much blow by your rings have. Particularly on a turbo, the pipe on the passengers side should be connected to the inlet of the turbo but after the afm.People who've disconnected this pipe on forced induction cars have experienced oil burning problems. The canister you are refering to is probably the fuel tank vapour charcoal canister and theres no benifit to removing it.