Smoke machine

[Jerm7]

Well let the fun begin.

Freshly built motor and it makes smoke and lot's of it, Thought turbo at first so I swapped it. The 2nd turbo did not fix the issue then I found oil on 3 of the spark plugs. I removed the pvc system plugged it off and removed the oil cap to check for blow by and nothing not even a hint of air coming out but I preformed a leak down test anyways and it shows around 15%-20% leak by on all cylinder, mind you it only had about 30 min worth run time. So I figured I tore a vale stem or two somehow so I ordered some new ones installed no difference. I also checked the intercooler for oil but found hardly a drip.

So I have pulled the motor back out. Found oil sitting in the lower intake runners of 1,5 and 6. Re checked everything, cylinder bore is almost perfect less then 1/4 of a thousandth out top to bottom and roundness, checked ring land gaps on 1st and 2nd rings, valve stems and guides etc. Everything shows in spec per tsrm and what my books show. The only thing I did forget was oil squirters. I know, I should know better. So this leads me to my best guess. I have shimmed the pump and it holds around 25-30 psi at full temp, could the oil squirters be held open and saturating the cylinder walls with oil so much that the oil rings can't control it enough so it's getting to the top end? This truly has me stumped because this is not my first 7m I have built but it is my first time having this issue with one. Any other ideas would be of great help. Thanks Jerm

 

[GrimJack]

No chance it's the oil squirters, that wouldn't account for oil in the intake.

Why did you rebuild the engine originally? When you did so, did you pull off the intercooler & piping and clean it out, or might there be a lot of oil from prior to the rebuild sitting in there, causing problems now?

 

[Jerm7]

I bought the car with the head off already and it sat like that for a year the cylinders rusted up. I used a spare block I had to rebuild the bottom end with. Just honed it enough to deglaze it so the new rings would seat. The upper intake is dry and all the upper IC piping and the IC was off the car. I got about a teaspoon full out of the bottom when I was hunting for the problem. It's really bad when you let it sit and idle for a min or two then just bump the gas a bit and it will spew out a gray cloud of smoke so thick you can hardly see the car, it's like I'm dumping oil down the intake. the first turbo had oil in the down tube but the second did not but the smoke hardly got any better.

 

[Suprapowaz!(2)]

Oil drain tube backing up? The longer you let it idle the more oil builds up, seeps past the seal, and starts dumping into the exhaust? It's just a guess. Did you happen to notice the turbo elbow and beggining of the downpipe wet with oil when you changed your turbo?

 

[Jerm7]

Sorry for the lack of posting, works been keeping me busy last few days.

I checked drain back holes, and the tube. I cleaned everything prior to re assembling the engine. With the first turbo there was but not with the second. I noticed once I took the exhaust manifold off all 6 exhaust runners were sooted up really bad. I'm starting to lean towards intake guide or ring problem.

I got 24 new guides all exhaust, the only difference is the exhaust guide is 1/8th in taller. my idea is to use them on the intake side also to raise the guide height up some to help with the possible oil control issue plus the guide them self have groves to help control oil better also. I can get some pics to show you if you want to see.

 

[nothingbetter]

do a compression check and let us know. That will anwser your ring issue. Bu tkeep in mind that if theres oil in the cylinder when you do your compression check your results will be effected. But its a starting point.

 

[wterryinftey]

So it looks like this...... http://www.youtube.com/watch?v=EhG91RTdAYI

Im still trying to figure out mine too, same circumstance though. Fresh rebuild on the 1st startup...smoke.

 

[Jerm7]

Yup, just takes a min or two to start. If I rev it a few times it's seemed to clear up some then it starts back. I ordered some new .020 pistons so I've taken everything back apart and gonna bore and hone it. Hopefully fix's the problem.

 

[Jerm7]

I didn't forget. Sorry for the delay on the fix but I wandered off into getting a few other things done on the car while the motor was out. Main thing being some mods to the transmission thanks for some help for a transmission friend of mine.

Long story short the motor runs like a champ now and no more smoke. A bore and hone job with new pistons and rings solved the problem. I got some bugs to mash out but other than that it runs like a top except for when it shifts under full boost it kinds pops and has a power drop for about a 1/4th sec, just enough to kinda let you come forward out the seat some but then takes off again. But I'm happy motor is strong and idles smooth and most importantly no more smoke.