Cylinderhead ventilation - greasy plenum...

[Lt86]

(03-31-2015 01:22 PM)Dave W Wrote:  After rebuilding my 4AGE 16V motor, including new valve guide seals I used on average about 1 Qt of oil per 1,500 miles. A few years later I pulled the intake manifold off to install a thermo gasket between the head and manifold. What I found in my newly rebuilt engine, was a lot oily $hit in the ports and head. I was running my oil breather tube “stock size” to a small one pint dump can then back to the intake manifold. But I was drawing such a high vacuum that engine oil was being suck into the motor thru the intake system. I changed the breather system to run straight to the atmosphere. I then took a 1,700 mile trip and I did not have to add a drop of oil. The 4AGE motor needs a larger then stock breather hose and a BIG dump can for the engine breathing system. A 2nd option would be to install a real PVC valve on thr breather hose. Dave W

Well, this is my concern. If I put a piece of cardboard behind the exhaust it starts to decolour from the spray caused by the exhaust (at idle!). Even though it could be my cylinderhead needs a rebuild, I was very surprised to see how greasy my plenum was. For sure this is sucking in oil. Thing is though, I don't have a dump can in between the breather hose from the head to the plenum so I don't know why it would draw so much oil.

So running the hose straight to the atmosphere with a small airfilter on the end would be OK? I would block the plenum opening on the other side.