Okay. I'll try to be brief: Currently running 9 psi on a recent Majestic rebuild / upgrade. Before the rebuild, after freeing up the exhaust, replacing the fuel pump, and putting on a cone filter, I was getting a pretty good plume of smoke on redline shifts. I figured it was the turbo, so I had it rebuilt. Right from the very first run with the new turbo, the same thing is happening. Maybe its not the turbo?



It really doens't smoke at any other time. How can I tell for sure it's the turbo? Any other likely sources of this smoke?



https://www.nopistons.com/forums/pub...1047683561.gif



Thanks for any help you can offer.



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Whats your oil pressure? Are you using the stock feed line? Are you premixing?

If you want to know for sure. You can take off the turbo and inspect the turbine housing and turbo exhaust manifold for oil. If you see oil in just the turbine housing then its the turbo. If you see oil in the exhaust manifold then its the motor. You can also remove the return line to be sure oil is actually flowing through the turbo. I have heard of rebuilds from Majestic going sour.



Here is what my blown turbo looked like.

Reads about 60 psi on the stock gauge with a new sending unit. Yes, I'm using the stock feed line. I tested flow before I hooked everything back up, and it flowed quite well, supply and return. No premix--stock OMP.

Even prior to the rebuild, the exhaust manifold and turbo exhaust housing were oil-free. This car sees only occasional use, primarily at the strip.



And oh yeah, the engine has just over 100k on it. https://www.nopistons.com/forums/pub...IR#>/blink.png

Nice pic, but the inside of my turbo was dry and brownish-looking--nothing like that one.

um you can try the rotor oil seal o ring test and start it cold and rev it to 5k or so and see if you get smoke

I guess I'd better go do that.



Is that a BIG O-ring? Like where the side seals are?



Sorry to sound ignorant, but I've never had one of these engines apart....yet.

yeah its on the sides of the rotors. its hard to tell the pcv from the engine from the turbo when these things smoke

What's that? PCV you say? Hmmm. It's not in my Haynes. Gotta go check my FSM....



You mean PCV as in PCV valve right? Positive Crankcase Ventilation?



I see a reference to a "Purge Valve". Is that it?

yep, make sure its hooked up right.

Okay. Thanks very much!

Will the smoke at 5k on a cold engine be VERY noticeable if the O-rings are shot?

I have noticed some smoking on cold starts, but not a lot, and it goes away immediately.

I have been experiencing exact the same thing , even went and got my turbo rebuilt with like you with the same effect. It has since gotten much worse and I am now having those O rings replaced (along with some other stuff) . I tested mine by capping off the turbos oil supply and holding back the compressor from turning, then starting the motor and revving it up a bit, after doing that I still saw the smoke so , I knew it was the motor.

check itnercooler piping, check the turbo exhaust housing. if u see no aoil anywhere then its most likely teh oil o rings

a puff or 2 at startup is normal, they run really rich. the 2 posts above this work too, we've also disconnected the turbo oil feed and held it stopped.

Well, I took the car out today. Revved it cold up to 5k. There was pretty much the usual amount of smoke on startup, and no additional smoke from running up to 5k. I drove it for a good while down some back roads, flooring it in third up to 5500 or so, then shifting to fourth. At each of these shifts, I got a large cloud of what looked like oil smoke. After some more experimentation and observation, I determined that the smoke would appear just as I re-applied throttle after the shift.



I'm guessing I'll need to rebuild this one or buy a rebuilt engine. With all the horror stories about rotten pineapples and shoddy shops, I'm not sure where to go. Not exactly where I wanted to be near the start of the racing season, but that's just the way it is.

this is EXACTLY what started to happen with my motor , I am almost sure its the oil control O rings .I will be pulling and opening up the motor this week so I'll post what I find.

If the oil seal o rings are going bad- they will get progressively worse and usually cause an increased prewssure inside the crankcase. This will cause your turbos to 'run dry' and then you can happily have everything rebuilt.

I found this out the hard way.

John

There is a good chanch the puff of smoke is actually fuel... When you let off the gas and the TB closes there is still fuel in the manifold that has already been injected that gets pulled threw the engine with out the air needed to burn it that will exit as smoke usually in the color of blue, if there is a lot of extra fuel it will be black.