anubis512 Posted January 29, 2017 Share Posted January 29, 2017 Hey guys, I've tried to do my due diligence in searching the forums, but I can't find anything really talking about my question. I just got an RB25DET engine in my garage that I'm preparing to swap into my 280z. While messing with the engine, I noticed the air inlet/discharge piping to the turbo were oily. The copper coolant lines and coolant passages in the block also appear to have some oil residue or some sort of black buildup. My friend was saying the oil in the air part is common for RB's and that the buildup in the coolant lines may be from the Japanese not using the same coolant type as we do. I looked at my L28 with a boroscope and the coolant passages on that are very clean, as is the copper heater tubing. The engine holds compression but maybe it had a blown head gasket previously or something? Or could the turbo be leaking oil into the coolant/air systems? This is my first time with a turbo engine so sorry if this a dumb question. Quote Link to comment Share on other sites More sharing options...
winstonusmc Posted January 29, 2017 Share Posted January 29, 2017 What does the vent from the intake go to? Does it go to the stock rubber intake pipe? That's a common place for oil to come from. RB motors never had a stock catch can, so they commonly get oil in the intake on hard turns. Quote Link to comment Share on other sites More sharing options...
anubis512 Posted January 29, 2017 Author Share Posted January 29, 2017 Yeah that's where it was connected. Do the stock turbos leak a lot of oil typically? I would've thought a small amount would be normal, but this seems like a lot. Also the coolant system appears to be very oily. If the turbo isn't contaminated the water lines with oil, I guess it could've had a blown head gasket at some point and gotten the coolant channels oily? Not sure what else could explain it. Quote Link to comment Share on other sites More sharing options...
winstonusmc Posted January 29, 2017 Share Posted January 29, 2017 The vent will introduce oil before the turbo. Pull the intake pipe off the turbo and look. It should be just as oily. It's normal and a catch can will remedy this. The only place that I can think of that oil and coolant can mix is the head gasket. Check the oil in the pan to see if it's milky, mixing occurs bother ways. Quote Link to comment Share on other sites More sharing options...
anubis512 Posted January 29, 2017 Author Share Posted January 29, 2017 Yeah its not milky. I guess it was a previous event or something. I took a boroscope to the cylinder tho and it doesn't look too promising? One looks like oil/sludge getting by the piston, and another seems to be a damaged piston? Looks like you can even see debris at the cylinder wall @ like 7oclock Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted January 30, 2017 Share Posted January 30, 2017 Sorry to say, but it looks like detonation damage to me on the piston tops. Quote Link to comment Share on other sites More sharing options...
anubis512 Posted January 30, 2017 Author Share Posted January 30, 2017 Yeah, I didn't think it looked too good either. Hoping to get the head off today and get a better look Quote Link to comment Share on other sites More sharing options...
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