Ok, so I started my brand new rebuild friday and let it idle. Before the thermostat could even open I notice smoke coming from the turbo. Not out the exhaust, coming from the turbo itself. To be specific the smoke appeared to be coming from the middle section between the compressor and the hotside housings, as if the middle section itself were smoking. So I shut it off to think.....

After discussing my problem with a friend we figured that the smoke was most likely oil that had accumulated around the turbo after 23 years or during assembly that was burning off, so I started it again (after de-flooding for 10 minutes of course, lol.)

Once again, after about two minutes smoke started coming from the turbo, so I let it smoke to burn off. The smoke didn't go away, it stayed constant, until it practically started billowing from the turbo. At this point I ran around to shut it off, but in that time the engine stumbled and shut itself off.

After further deliberation with my comrade we concluded that since there is no smoke coming from the exhaust, there is no loss in oil and I have great oil pressure that it must be a leak in the gasket from the oil drain line. I haven't noticed any oil leaks around the area when the engine is cold, but when it gets warm (at least the turbo anyways, remember this thing hasn't even been to op temps yet) and after smoking, I do see oil pooling between the turbo and exhaust manifold viewing from underneath the car.

So my hypothesis:

When the turbo gets hot, the flange for the drain line expands allowing the faulty gasket to leak oil, dripping or running onto the hot exhaust manifold causing it to smoke, the hotter it gets the more fluid the oil gets and the more drains out, hence the increase in smoke as the turbo got warmer.

Tomorrow I'm draining the oil and pulling the turbo off to inspect the gasket / replace it and see if that solves the issue....

So any opinions? Anybody seen this before?

 

Sounds like you're on the right track. Check both ends of the pipe for leaks.

 

I had a similar issue , you neeed to check you crank case pressure and you hose routing . You may have ait wrong and cause the crank cae pressure to build up thus pushing the oil past the seals and buring off.

Is the turbo a reuild too?

 

Alright! Well after working in the pouring rain, literally, I got the turbo off w/ the motor in the car, replaced the gasket and re-installed it. started her up and no smoke, except for steam from the wet, newly wrapped downpipe. It's back on the road tomorrow. However I'm a little iffy cuz I used "the right stuff" 1 minute gasket to make the seals.... seems to work no problem but I'm considering removing the turbo again after I get gaskets in....

 

the right stuff is amazing but i have never used it in a high heat application like a turbo before. i wonder if it will hold up... probably will actually.

 

I would be very surprised if it holds up.
Temps from a rotary are 1100F + on load

 

Thats what I'm worried about. I've got a heat blanket around the hotside, but I'm still going to pull the thing again monday. I'm getting pretty good at pulling the freaking turbo off, lol.