A CB tower with 1 (top) outlet to atmosphere through a flap valve to stop sucking when on overrun works for me.

If an engine is breathing really heavy I'd look to solve the cause not the effect.

The problem here will be a high revving engine in a case originally designed for a 1100cc engine that would never see above 4K rpm.

Performance engines generate loads of internal pressure due to the crank spinning at high rpms, the pistons flying back and forth, piston blow by, etc, etc.

You need some method of reducing this pressure or it will suck in the valve cover gaskets (low pressure in the head as a result of high pressure else where) or oil leaks due to high pressure forcing oil out of the case.

There is a good article covering this topic on the Shoptalk Forums explaining what VW/Porsche did over the years to combat the issue on stock engines, and what you can do to address the issue on a performance engine.

Ok here are some pics.

I know all engines are different and certain thing work well on some but not on others and it has to be to your own style.

This has worked for me and I no longer get any oil being pumped out of the dip stick.


CB tower with all the hose's .





There is a small filter on top of the CB tower to allow relief.

Testa

Here are some old piccies of my 2332cc engine - I have never really done 'shiny' some of the parts have changed since these pictures, but the breather system is basically the same.

Rocker cover take off


Jaz 1 quart breather catch tank


Additional small filter on the oil filler


The third connection in the middle of the catch tank was for the Berg 5 gearbox breather connection - I no longer have the Berg 5, the 'Kafer Cup' brace, or the wheelie bars, and various parts of the engine are currently located in Harrow, Leeds and the Isle of Harris. The engine was taken apart after I sheared all 8 dowels off the crank around 8 years ago and has yet to be put back together again .

To my knowledge, this setup never had any leaks or sprayed any oil in several years of racing.

My tired type IV 2.0l engine however, did successfully spray the track with oil mist from a small oil filter just above the normal oil filler area (no tinware or cooling on this occasion), I even have in car footage somewhere, of the camera being covered with oil from this run.