I've done some searching, and I've found some others who have posted this problem, but I haven't as of yet seen a good answer.
I got done putting my car back together today after doing head gaskets. While I had the turbo off, I checked the shaft play. The end play appeared to be zero, but there was a little bit of "up and down" play. As long as I can remember, the turbo shaft has been like that. For reference, it's a TA49 with a Preciaion .85 exhaust housing.
After I test drove the car, I was revving the engine in my garage checking for problems. I noticed that every time I revved the engine hard enough to spool the turbo (and yes my little TA-49 can easily spool up while revving the engine in park), a substantial puff of smoke would come out from the bolts that hold the exhaust housing onto the center section. This seemed strange to me. Maybe it's been doing this all the time, because this was a rare time where I was running the car without the turbo heat sheid on it. Interestingly, I confirmed that there was no smoke coming out of the tailpipes (with the help of my Dad). During the drive, the turbo spooled fine, very aggressive as it always is. The smoke didn't smell like burning oil, but I'm not 100% sure it's not oil. I checked the exhaust housing bolts with a hand wrench, and they appeared to be tight.
A little more background - while I had the intake off, I noticed that the bottom of the inside had a thin "shellac" coating on it. The plenum appeared OK - maybe just a very light shellac coating. I still run EGR on my car, so I assumed the shellac on the intake came from that. The IC pipes also appeared OK - no signs of heavy oiling.
So, is this normal? I know the seal between the center housing and exhaust housing is probably not 100% perfect (just metal-to-metal contact with no gasket). So, for those of you who have smaller turbos, do you see a puff of smoke from the exhaust housing bolts when you rev your engine?
Thanks,
I got done putting my car back together today after doing head gaskets. While I had the turbo off, I checked the shaft play. The end play appeared to be zero, but there was a little bit of "up and down" play. As long as I can remember, the turbo shaft has been like that. For reference, it's a TA49 with a Preciaion .85 exhaust housing.
After I test drove the car, I was revving the engine in my garage checking for problems. I noticed that every time I revved the engine hard enough to spool the turbo (and yes my little TA-49 can easily spool up while revving the engine in park), a substantial puff of smoke would come out from the bolts that hold the exhaust housing onto the center section. This seemed strange to me. Maybe it's been doing this all the time, because this was a rare time where I was running the car without the turbo heat sheid on it. Interestingly, I confirmed that there was no smoke coming out of the tailpipes (with the help of my Dad). During the drive, the turbo spooled fine, very aggressive as it always is. The smoke didn't smell like burning oil, but I'm not 100% sure it's not oil. I checked the exhaust housing bolts with a hand wrench, and they appeared to be tight.
A little more background - while I had the intake off, I noticed that the bottom of the inside had a thin "shellac" coating on it. The plenum appeared OK - maybe just a very light shellac coating. I still run EGR on my car, so I assumed the shellac on the intake came from that. The IC pipes also appeared OK - no signs of heavy oiling.
So, is this normal? I know the seal between the center housing and exhaust housing is probably not 100% perfect (just metal-to-metal contact with no gasket). So, for those of you who have smaller turbos, do you see a puff of smoke from the exhaust housing bolts when you rev your engine?
Thanks,
