Race 964 3.8 oil breather problem

[Cookie Porsche]

I have a 964 3.8 engine in my racecar. Last year it ran super - no problems.

The oiltank sits in the front compartment. In 2005 we ran a pipe from the engine breather all the way to the front tank. From the tank we had a pipe into a small overflow tank in the front (fitted with a filter). Everytyhing worked fine.

This year we reconfigured the breather and fitted a 2 liter breather tank in the rear wheel fender. From the breather on the engine we run a pipe upwards before running through the 'sidewall' and into the tank in the fender. The tank is fitted with a small air-filter.

When driving normally (even using high revs) the tank is empty.

Today (first day out in the new car) we ran 10/10 on the track and the breather pushed out ALOT of oil - say 3 liters+ after a few laps... Why?

Needless to say the tank overflowed - rather messy affair.

Help. Tom

[CBRacerX]

Very likely this is a vacumn formed by the high speed of the car body (ask me how I know...). The way you used to have the breather is the most foolproof in my experience (again, AMHIK).

Chris
former RSR Replica Owner with a breather hose from rear to front

[racing97]

The Breather must run into the oil tank under a baffle then to a vent, which you probably had in your previous situation. The reason it occurs is oil wraps around the crank then shears at a little after 6000 or 6500, the path of least resistance is the breather. It will send a slug nearly a foot in length and the complete daimeter of the hose ID. If you ever use clear surgical tubing you can see it in the vent tubes running to the tank back and forth, viewed from inside the car. We used to dyno with clear tubes and it was amazing.

Best regards

[ANTONIO]

Tom,
I did have the same problems as you in a high hp 3.8TT engine, I run a 2qt breather at the tail end of the qtr. panel,at the rear of the right tailight(these been a 993), I split the breather hose coming from the engine with a "T" fitting, one going to the breather tank, the other going to the tank itself, it worked on to some extent, but I did still have some oil problems with these set up, but not as much, I finally fix it by running a hose from the drain cock at the bottom of the breather to the right lower valve cover, end of problems, you must address this problem, oil is bad for the track, but baddest for your engine,when it falls on the hot headers,it will cought fire in a snap, ask me, I know!!,cheers,Antonio.

[Cookie Porsche]

Thanks - back to the old system.

The oil ended up on my left rear tire - we had a really special 'moment'...

Tom