930 oil blow by

[liblake]

I have an 89 930 with less than 50K miles... After each track session or out on the street with pedal to the medal, after the car is back in the pits or back in the garage, there is a moderate size (18 in diameter) wet oil collection under the right side of the engine. Opening the deck lid, there is wet oil inside the intake of the air cleaner and around the right side of the engine. Engine oil level is midway between the marks. Mechanic and other Porsche owner have no idea what could be going on. Car runs fine, doesn't smoke, and otherwise shows normal oil consumption. Any thoughts or ideas appreciated.

[jwasbury]

The crankcase breather system goes to the oil tank and then is ultimately is plumbed back into the air box. For hard running in any 911 or 930, generally you want the oil at the low end of the dipstick. Middle is too high. Most likely you've got oil sloshing up the filler neck and into the hose that is plumbed back to the airbox. Being full thottle, once boost is up, that engine is sucking a lot of air, so it will vacuum up any oil that is getting to the breather hose.

I rerouted the breather line to a dedicated catch bottle to avoid this problem. Good idea for any tracked 911 or 930

Alternatively you might have a ring/piston problem. A leakdown would tell you for sure.

[liblake]

Appreciation, Jacob.... leakdown test several years ago was good... I think you've provided the answer. Will talk to some 911 racers about re routing breather line.... although lately the air cooled 930s market values have sky rocketed so maybe use my 80 SC for the track....

[turbodave930]

I agree with the above. I always have to run my 930 at the very low end of the oil level. Otherwise, you soak the intake. I've been using the oil level gauge. I run it with just the slightest wiggle in the gauge. Been fine for 100 +\- track days.

[T77911S]

with my 77s and my 930 i find it better to run oil low. especially with the 77. it would go thru oil very fast until it got down low then it would go very slow.

i have the 930 a little on the hi side and i have oil coming out too.

i have always used the gauge too. verified it to the dip stick. thing is right now MOST of the time the oil is middle of the gauge at idle. once in a while it goes very hi. i prefer the middle of th egauge to be the highest it goes.

[Robbbyg]

I had the same problem cured by putting 9 mm bb where there was none,
I like to keep my oil on the high side only for the extra few degrees more oil helps with engine cooling , necessary where i live in hotter location,

[Maltese Falcon]

I've been running a dedicated breather can for my street+DE 3.3 biturbo. I open the bottom drain plug of it once a year, and barely get a drop of oil. Just a tig welded 4x6x8" aluminum box with some 3/4" nipples, and a drain plug.