oil in intercooler

[Alan L]

So I was prepping the car for the track. It has been sitting a while. But lots of smoke on startup. Then it cleared in a minute or two.
But I was also changing turbos and noticed oil in the IC.
So what are the options as to how it could get there. Thats the air intake side of things.
I did have an issue last yr and tore the engine down twice to try and sort it. Oil dribbling into the headers on sitting. Finally I changed a head (#1) on the errant cylinder and the problem seemed to go away. Never found an issue with the old head - sent it to two shops. Also noticed a few days ago a drip of oil on the header stud for #4. Wondering how that could get there. So now wondering if I ever found the original problem.
Engine seems to be running OK. Previously it was fouling #1 plug with oil.
Thanks
Alan

[Alan L]

So after a bit of searching on this forum I have a few clues. Nothing much comes up for 'oil in intercooler'. Lots of stuff about 'oil' and 'intercoolers' but not the whole package.
But what I am thinking is it has to be a turbo issue. Not necessarily the actual turbo. That seems to be running OK. Should be clouds of smoke if it has failed. Thinking the drain back system may be faulty. Not much to go wrong with it. Long time since I checked it - presuming it is still fitted.
There was oil pooled in the bottom of the turbo cold side which I saw as I changed turbos. As far as I can figure there is no way that could have drained down from the intake side of things - no oil there. So I am thinking the oil is draining in to the turbo. Then when it fires up it shoots the oil thru the IC and intake runners. Then drains down into whatever cylinder has an open I valve.
That may explain my problem last yr when I was fouling a plug with oil. It did seem to be only #1. But my and 2 other shop inspections could find nothing in the head, and I pulled the piston - more than once, to check rings. So it was a mystery when finally put back together. Now it seems like #4 has been draining down. But it may all be connected to the turbo flooding with oil when sitting. So the lack of explanation for the previous problem may be connected to this.
Can't see what else would be causing this. Racing in a few days - so hopefully nothing more than a faulty drain check valve. Will have a look.
If anyone has any other suggestions - fire away.
With the other turbo on it will be interesting to see if it still pools oil.
Not at car right now.
Alan

[gsxrken]

I’m interested in what you find. I’ve always had an oily mist on the up-pipe that I’ve wondered about and assumed it was just a feature of these turbo’s engineering. It’s very slight and hasn’t worsened. Mines an original 7006. Has you’re been rebuilt? I’ve heard there are differences in the turbo seals that can be an issue

[mark houghton]

On my past 930, running with a 7006 turbo, I always had light coating of oil in the up pipe - which I attributed to turbo seals wearing a bit. She would blow a puff of smoke at startup for a second, either from the oil in the up pipe/IC or more likely seeping past a valve guide(s) while sitting for a few days.

[dannobee]

Alan, are you sure it's not the crankcase vent dregs seeping in through the hose to the air cleaner then ending up in the intercooler? In my experience, damned near ALL turbo cars that I've ever worked on had oil in the charge pipes. Across all brands.

How much oil are we talking here? A few teaspoons? Or significantly more?

Also, search "crankcase vent" here for more info instead of "oil in intercooler."

[Alan L]

Thanks guys.
So, yes 7006 turbo. This one I don't think has been rebuilt. I have about 4 turbos, more if you count the bits (blown ones). So I loose track. I have a fresh rebuilt 7006 (Evergreen) sitting in a box. I think this one is a spare that hasn't been rebuilt. I have just fitted a used 3DLZ. Which I have yet to run.
The amount of oil sitting in the bottom of the turbo was about a teaspoon or two. As far as I know it isn't blowing smoke when fully working. The intercooler drained about a teaspoon of oil on the floor when I removed it (bit shocked with that).
I have a K&N filter. My crankcase vent goes into a catch can.
The mystery is the fact I tore the engine down twice because I had oil dripping from a cylinder when I fired it up. Would only run on 5 - the oil was splattering on the plug. Found nothing in 2 teardowns and leakdowns are around 2% on all 6.
This time oil splattered out of #4 (leaking past header slip joint).
So I am thinking whatever is going on here with the turbo is the cause of my 2 teardowns - which never found a smoking gun. But the problem went away (or seemed to) when I swapped another head in.
I am now thinking I simply cleared an oil backlog in the system with the teardowns. The car has pretty well sat since then, til now.
Will do a 'crankcase vent' search.
Regards
Alan

[908/930]

Does the inside of the intake manifold have any oil film? You checked that last time and it did not, not sure if a seal on a turbo can work intermittently. Is the oil catch can for the turbo clean?

[Alan L]

If you mean the pancake manifold I haven't disassembled that far, this time round. I am guessing it would be wet with oil. Hard to see why not if the IC is wet with oil also.
I will check the catch can when I get back to the car later today. But it usually has about a teaspoon of oil in it. I don't think there is any in there basically. I had that can off when I tore the engine down. It hasn't done any work since. And there wasn't anything significant in there last time.
My strong suspicion is it is feeding thru from the turbo end of things. Going to check I have the anti drain valve in there.
Alan

[908/930]

Agree that the manifold is likely oiled, but you did check that when you were tearing apart your engine months ago and reported it looked dry. Scavenge pump acting up? I remember you had clearance problem on a spacer that you machined some extra clearance into.

My turbo seals do leak oil, up pipe wet and some oil in intercooler and sometimes smokes for 5-10sec at startup. No other complications yet.

[Alan L]

Your memory is better than mine . Not hard these days.
The scavenge pump was another thing I was going to check. First I need to see if the anti drain valve is there. If for some reason I took it out, I suspect I have the answer. If it is in place I need to keep looking. Yes I do recall some scoring on the face plate of the scavenge pump and could not figure what had happened. I think I machined it to a clean surface.
Thanks for the tips. I need to keep poking at it. It is more than a small amount of oil at least initially.
I am pretty sure the engine is sound - so it has to be this end of the system.
Regards
Alan

[Alan L]

So the oil drain back check valve and spring were in place.
The scavenge pump is working fine. The car started up today with not a puff of smoke. Heavy smoke for 10-20 secs yesterday - on the 7006. Now the 3LDZ is fitted.
So it seems like the turbo is at fault. Hard to figure because while there was oil in the bottom of the 7006 , the drain valve is in place. So I am thinking all should be good with the 3LDZ and 2 engine teardowns previously were likely not needed.
Now someone hit me with a blunt object - on the head preferably.
I have been down this track a few years before. Had oil smoke on the track - not bad, not clouds etc, but a trailing wisp, esp on overun/downshifts. The turbo had just been rebuilt, so eliminate that. Must be in the heads. So engine out, 6 other heads fitted. Same issue next meeting. Well it must be in the pistons - they were well worn in. So engine out again, 6 new P/Cs fitted (had them sitting in a box). Same problem . Only 1 thing left. Change the turbo. Problem solved.
So hopefully I learn a lesson this time - never trust a rebuilt fresh turbo, always suspect the turbo first if you have oil in the intercooler, or oil smoke. Easiest test - swap in another turbo before tearing an engine down.
I am feeling optimistic. It doesn't quite all add up, but seems to make more sense that swapping the heads over last time, and finding oil in the IC.
I will know for sure by the end of this coming weekend.
Alan

[930cabman]

a small amount is normal in my experience. Mine always has a coating of oil and runs fine without excess smoking

[Bucketlist]

Great to see your headed out for another season of racing and using your car the way it was designed. We all respect your knowledge and motivation and look forward to hearing about your experience.

[gsxrken]

Originally Posted by Bucketlist

Great to see your headed out for another season of racing and using your car the way it was designed. We all respect your knowledge and motivation and look forward to hearing about your experience.

+1
It’s not just Alan’s knowledge or his willingness to help on many posts… with the amount of times he nonchalantly tore down his engine he also sounds like a Terminator. The mental hurdle of having to redo something has broke me before, and I’ll walk away until I’m in the mood to do something. That has been months at times, I’m ashamed to say. Not Alan. Respect!

[Alan L]

Thanks guys. Hit the track tomorrow.
I will be buried with this car - and my SC. They keep me alive.
I am 72 in a week. I hope to be racing this thing for some time yet. Got a road trip 1000km south next month.
This car is a love/hate relationship - it drives you nuts at times. Then it all comes together and there is nothing like it.
We are live in TV this weekend - hope I don't crash :-)
Regards
Alan

[Alan L]

[Bucketlist]

Originally Posted by Alan L

Now that is just cool.....
At '77 I quit autocross a few years ago and the closest track the PCA uses is 9 hours away. I don't think I am too old, just lazy.
Good luck!

[krasuskyp]

Originally Posted by gsxrken

+1
It’s not just Alan’s knowledge or his willingness to help on many posts… with the amount of times he nonchalantly tore down his engine he also sounds like a Terminator. The mental hurdle of having to redo something has broke me before, and I’ll walk away until I’m in the mood to do something. That has been months at times, I’m ashamed to say. Not Alan. Respect!

NOJOKE Kenster - this deserves a repeat!! Admirable / impressive, Alan - and always here to HELP OTHERS.

Great pic, and best of luck to you on track and on road trip!! Onward / upward!!!

Mine randomly smokes the "healthy puff" at startup... no rhyme / reason. Can be stone cold for daaaze / weeks, fresh hot start, or anywhere in between. Sometimes does it, often doesn't. Fut the wuck!!?? Always "fun" @ the carz n coffeez, lotttts of chukklez and looks from allllllllllllll the non Porschefolk, unsurprisingly. Siiiigh. Part of the charm, I s'pose lol

[908/930]

71 and still able to drop and rebuild the engine out of your 930, thats impressive. Must be all the clean air. It is great to see a 930 still on the track, looking at the other cars and current parts prices I'm pretty sure it also costs the most to keep it on there.