Oil Catch Can

[BobWrinkle]

Hey guys you all seem to be running oil catch cans...

What do they do?

I get from the name that they catch oil.

Are they used to stop the engine from running out of oil while cornering, braking, accelerating etc?

Cheers for your help
Cade

 

[3zercrowd]

Hey dude,

Ok the oil catch can is to "catch" unwanted oil vapours going into your engine from the crankcase ventilation line from your rocker cover to the front of the turbo, or into your intake. You dont want to be burning any extra oil or any at all in your combustion chamber as the oil gives you a lower octane rating and can harm your engine.

Anyone else got any other comments? :wink:

 

[bazeng]

sounds about right

but basically, the oil comes out of your rocker cover due to the crank case pressure (usually when revving / cornering could do it also, i've had a honda piss out oil when hard cornering, we had to put a catch can in and also plumb it back into the sump)

but for the mitsu's, it usually happens when revving the engine..
the can keeps your intake clean and prevents the oil vapors from reducing your octane..

we have 2 vents on our rocker cover, the pcv (which goes into your intake manifold directly, located on the top left corner), and one that goes into your intake pipe before the turbo (located on the left centre)

the pcv will work only when there is vacumm, so remove that valve and install a barb when installing a catch can.

as for the other, take that straight the the can,

covers could be drilled out and tapped with -6an size fittings to allow you to vent more gas..

remember its illegal though, but isn't everything?

 

[BobWrinkle]

sounds about right
the pcv will work only when there is vacumm, so remove that valve and install a barb when installing a catch can.

remember its illegal though, but isn't everything?

Whats a barb?
And i thought it wasn't illegal if the catch can isn't vented.

 

[bazeng]

barb is a brass hose fitting

yeah, it is only illegal when venting to atmo..
but thats the only way to have it

=)

 

[BobWrinkle]

atmo?
atmosphere?
I saw 2 diff styles one with air filter one without??
Which is best? One was $30 and the other was $80 which tells me something
But what are the benefits of it being vented?

 

[bazeng]

no oil fumes in your intake

thats really the only diff

but also, the vac created by the intake could help the piston rings seal against the bore also..

but most high hp applications just vent to atmo

the street legal ones plumb it back into the intake

 

[87vr4]

the pcv valve only open on vac?

my haltech gets its map signal from there, & it also runs pressure to tha fule reg.... should it be closed when theres pressure in the intake manifold??

might explain why it runs like a heap of shit off boost, what are the two other vac lines coming out of the intake on the right hand side (when facing the car from the front)


***i had a look at the service manual & found out exactly what the pcv valve is, its just a ball valve thats closed with pressure & open with vac from the manifold