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Rb25 Blue Smoke

grothie

By grothie,
in Engines & Forced Induction

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grothie Apprentice

grothie

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My rb25 is blowing a fair amount of blue smoke under hard acceleration. I did a compression test and it came up 160 across all 6. There is no smoke on idle or slight revving only when I give it a good rev. I replaced the turbo with a brand new one and the return doesn't seem clogged or anything. Has all brand new feed and returns. Also I don't have a down pipe on it at the moment and it doesn't make full boost until about 5500 or so on a t04e. The blow off valve doesn't go off and there is no sound of releasing pressure when off the throttle. All cooler pipes are tight. What would be the cause of excessive blue smoke?

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grothie Apprentice

grothie

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it has a brand new turbo on it with 1.2mm restricter, what are the signs of bad valve stems? ill give it a boot full and it will blow a shitload of blue smoke on hard acceleration, but if i keep boosting it the smoke gradually gets less and less, so pretty much the more i flog it the less it smokes so to speak (no i dont flog it all the time lol)

which leads me to believe its valves as theres no time for vacuum to draw oil through the seals.... but theres no smoke on start up or just putting around under say 3.5k rpm

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scotty nm35 Grand Master

scotty nm35

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I have had to install two 0.9mm restrictors to some Garretts just to stop the oil pumping out of the seals, you can tell as the oil is unburnt in the dump. If it is burning it, it is most likely internal, but check the intake for oil first, it could be the compressor seal or just leftover oil from the last turbo failure...

T04e is a pretty big turbo, I hope you haven't done the ring lands from booting it without tuning first. It will also be more responsive once it's tuned properly.

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Trozzle Grand Master

Trozzle

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As stated above, potentially the oil control rings. Possibly also valve stem seals - will a leakdown test return poor figures if valve stem seals are shot? Or would they not allow enough air past?

Your other symptoms like the BOV are almost certainly unrelated :)

I'd start at the beginning of the system (filter and intake pipe - rocker breather return) and work your way to the exhaust. You've ruled turbo seals out (well, you haven't - but would be f**king horrible bad luck if you had 2 buggered turbos :P), so that leaves you with the rocker cover breather return, valve stem seals, and oil control rings to point at.

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