EFI conversions - Show me your oil vent setup

[HelmetHead]

Having joined the elite ranks of the 930 Pelicans a few months back, I thought I would ask for some advise on oil vent systems...

My 87' 930 has been converted to EFI/carrera intake with Motec mgmt..etc..etc. and i've been chasing down an oiling issue which I believe I've finally found the culprit? I've been blowing oil into the intake and through the turbo into the IC and subsequently back into the engine from what I believe is the crankcase vent line coming from the stock oil seperator 930-107.321.01..



Its not a huge amount of oil, but its enough that when i park the car...oil drains back down from the IC into the turbo housing and then onto my garage floor

As I'm sure i'm not the first guy to have these issues...I wanted to see what the Pelican knowledge bank had to offer up.

Peace,
Einar

[fredmeister]

My 79 930 does not even have the separator unit. I wonder when Porsche installed these and why. Mine seems to run fine without it. You may want to remove it as an option...don't know what that will hurt.
Anyone have more knowledge on its value?

[HelmetHead]

Thanks fredmeister....I thought about just yanking it, but the lower hose hooks to the oil tank...guess i could plug that line/fitting?

[930gt-40r]

Originally Posted by fredmeister

My 79 930 does not even have the separator unit. I wonder when Porsche installed these and why.

I think this had something to do with emmisions.

[David]

I did say I'd send you some pics the other day at your house, didn't I.

OK, OK, here they are







There's a hose from the engine to the lower bung on the oil tank neck and a second hose from the upper bung on the tank neck to the breather tank.

[TimT]

Granted this isn't a turbo, but this is what I have on my ride.. Note the oil tank is in the front..

I have a hose from the front tank, routed up along the roll bar, to the breather tank, and the crankcase vent also connects to the breather tank...

there is petcock on the bottom so you can drain the spooge..



The big question is why you are putting so much oil into the intake? When the oil is hot and the engine running, if you remove the oil cap, what do the vapors coming out of the oil tank look like? are they pulsing? or just drifting out?

[fredmeister]

Originally Posted by HelmetHead

Thanks fredmeister....I thought about just yanking it, but the lower hose hooks to the oil tank...guess i could plug that line/fitting?

I dug out "upfixin der porsche" this weekend and found it written by The guru Bruce Anderson that in 1983 Porsche added this tank to the turbos to control oil vapors....likely an emissions change. I don't know if this recovers some oil from being burnt ultimately, but my 79 aint got one and you should be able to yank yours and plug the line to the oil tank.
I would love to see some actual data that claims the oil saved by leaving it and may look into getting one installed if it is benficial in that regard.
Like someone else posted above, you should not be seeing lots of oil vapor anyway, if you are then there is other problems going on you need to correct.

[magic930]

I have one very similar to 125shifter. I find that it collects more water than oil, so I suspect that plugging the lines is not a good idea.

[David]

Originally Posted by magic930

I have one very similar to 125shifter. I find that it collects more water than oil, so I suspect that plugging the lines is not a good idea.

Same here. When I drain the tank it's almost all water.

[HelmetHead]

Guys, Thanks for the posts. As noted above by several people...there might be other issues with this motor.

Story behind the car/motor is it came up on CL a few months ago for a $ which i figured i'd jump on with the possibilities of having to do some work. The car sat for a couple of years when I initially viewed it and it ran like crap...3 cylinders missing and blowing oil by the rings.. I have since put a couple of hundred miles on the car and the rings seem to have seated much more so than original...compression numbers are between 105 and 125 for all 6 cylinders (only one was at 105). Whilest tweaking on the valves, I also noted some pitting on one of the cam lobes, so there may be a rebuild in my not too distant future.

The oiling issue might also be due to my ignorance with oil fill levels....Like i added about a quart too much a few weeks back and puked oil all over everything. The oil blowby from the vent pipe has been a persistant issue which I wanted to eliminate, but as mentioned..there may be more serious issue.

I imagine the true test of blowby from the cylinders would be a Leak down test versus the compression test....but then again turbo motors are new to me... I'm much more comfortable with a holley 4 barrel and 8 cylinders.

Any other suggestions greatly appreciated.

Chow