toofast928

So we all know the 16v cranks whips the engine oil upwards and is drawn into the intake via the oil separator screen (oil filler). Why not fabricate a block off plate sandwiched between the block and the oil separator housing? Drill a 1/2 hole for crankcase venting. Sounds like a good idea. No need for a catch can.

Richard S

Devek already developed one...check their site for it. No need to re-invent the wheel.

Rich

toofast928

Thanks Rich,
I thought the Devek was a screen and not so solid. So for 1.00 piece of stamped steel the oil mist could be cut down. So such a simple solution why is everyone trying weird things like exhaust suction to aircraft catch cans?

GlenL

Because the baffle alone isn't sufficient?

I've plumbed in a catch can as well. Most people who track their 928s have a catch can. Or have a dry sump. Germans running the Autobahn report similar oil ingestion problems.

The other effect is that oil mist lowers octane and can cause detonation. This leads to further problems. Do not ask how I know this!

If it's a small problem on the street, like that occasional on-ramp blast, then the baffle might be enough. If there's already a big cloud behind you, then it may need further measures.

Direct splatter from the crank is one problem. Blow-by that lifts oil fog is another. There is just not enough volume in the crankcase to allow it to settle properly.

BC

I have installed an S4 style oil filler neck onto a 4.5L engine. We'll see how this works.

I drilled out the second hole in the base of the neck and will route both hoses to a vaccum valve inte exhaust ala Porken.

Steve J.

I have the Devek baffle. You can also install a stopcock / valve in the hose from the oil filler to the pan. Keep it closed except when filling with oil. Prevents oil from coming up from the pan when there is pressure in the crankcase from blowby or whatnot.

GlenL

The valve tip is only good for very early 928s. Later models have the filler tube extend down into the pan and below the fluid level. This fix prevented vapor from going up the pipe.

I tried this and it made the problem worse as the filler/separator would fill up and reduce the separator's effectiveness. The car did have serious issues, obviously.