Turbo Smoking...

surfnaked · 6-20-09, 11:20

It's been a long time since I've been on the forum, but I've got a 93 4cyl I boosted last summer. I'm running an IHI off an '88 turbocoupe with a -3AN feed line and 5/8" drain line....

I've always had an issue with the car smoking under boost... I thought the problem was poor drainage, so I rebuilt the header to position the turbo in a spot for a better drain, which is now straight down without any horizontal portions or obstructions...but still smoking...I had thought perhaps that the seals had been blown from the old drain, so I bought a rebuild kit and followed the instructions here on the forum, which went very well but it still smokes a lot. At this point I really don't know what to do...

I also recently rebuilt the exhaust, which I'm sure decreased back pressure making the problem much more noticable. It turns out there is a pin hole in one of the exhaust welds near the turbo, and oil splatters out of this whole onto everything within 10 inches of it... It seems to me the engine oil pressure out the sending unit would be a little high, but all the opinions I've gotten so far say the -3AN line without a restrictor should be fine for a non ball bearing turbo...

Any suggestions or ideas here?

~~Mark

**hgallegos915** · 6-21-09, 15:57

Are you sure its the turbo... I think maybe oil is seeping trough the piston rings under boost, or valve stem seals? Take out the turbo, turn the engine on for a while , let the oil in the pipes burn out or flush it and then rev it. Or just do a comoression test. If the compression rises when you add oil, bad . um seals?

**mx6guy505** · 6-23-09, 2:01

Usually if it is the turbo you will notice oil in the intake or the ic as well, this is due to the seals going to pot.

BUT I think it's your rings as well. You can do a compression test like stated above but a leak down test would be more up your alley.

Edit: Further more it doesn't seem likely that oil would spray out a pin sized hole in your manifold as well. A good test is to take off your down pipe and check for burnt oil.

**zlyricist** · 6-23-09, 19:38

if it only smokes under boost, perhaps your ihi was not a good candidate for a rebuild and had a worn turbine, so oil still leaks past the turbine seal

**hgallegos915** · 6-28-09, 3:20

if it smokes under boost, its bad rings i would believe.

**Stealth** · 6-30-09, 17:08

My guess is its the same problem everyone has, your pressurizing the crank case. Make sure the VC's are both disconnected from the manifold, and that you run a catch can setup with a check valve to prevent from pressurizing the crank case.

Easiest way to check for this is to look for oil in the intake pipes and intercooler.

When you pressurize the crank case it doesn't matter how good your drain is, the pressure is trying to go in both directions so it has no where to go but through the seals in the turbo. Alot of times, if you catch the problem early enough you can make the fix before the seals in the turbo are totally shot.

surfnaked · 7-6-09, 13:59

Alright, well thanks for all the advice guys. Unfortunately, I've been busy getting settled back into a new place for a summer semester...but I picked up an oil pressure gauge and threw it in there just to be sure, and everything looks fine as far as that goes. Hopefully in the next few days I'll be able to run a compression test and set up a catch can...

I'll let ya know hows things work out as soon as thats all done...

surfnaked · 7-9-09, 20:00

The problem was pressurizing the crank case...went out for a quick test drive a few nights ago and pulled the PCV to vent to atmosphere and that solved the problem. No visible smoke for a few days now. Just need to get a proper catch can setup and I should be set. So far seems good enough that I was able to catch the problem soon enough after the rebuild to not destroy the seals in the turbo!