HELP Crankcase Breathing Issues

[boosted88]

Hi having swapped over to an Evo III head in the last few months with the engine up and running I'll suffering oil being pushed out of rocker cover gasket and the small sump breather hose! Seems OK at idle but even a short drive coats the inside of the engine bay with oil. Before the head swap there were no issues with crank case breathing, bottom end had forged pistons and rods a couple of years back. Compression tester showed around 200PSI per cylinder.

Have changed the PCV valve between the rocker cover and inlet manifold that made no difference.

I'm using a SOHC oil filer cap in case that makes any difference.

Any ideas guys????

[MR Bender]

the twin cam motors need as much air as they can get!!
the stock breather mite be blocked?
i would take off the cover and get it cleaned.

or even better add another breather on top!

like this:

[boosted88]

Cheers for the quick reply, I have a spare cover and will look at modifying that one, did you change any of the internal baffles when you added the extra breather ports?

Cheers Paul

[MR Bender]

no i didnt but i should of!
maybe you should look into what the evo guys do.

[Xentro]

It's better to leave em in is my opinion.

You want to get the fumes, not the oil that cams throw around.

But be sure to seriously clean the cover after you done some drilling as you don't want metal bits in your engine.

[WANTSOM]

Two -10 fittings (one on each cam bank) as per Mr Bender's photo to an oil/air separator does the trick. As stated above, these motors need to breath.

Dont remove the shielding, just be super meticulous with cleaning out metal shavings etc from any drilling you do. Like, even when you think its clean, do it again.

[boosted88]

Cheers Guys have put two 25mm breather tubes to the catch tank and all seems good

Thanks again

Paul