CanadianEh!

iTrader: (4)

Hi Guys....I'm really frustrated and looking for some help. I'm running a stroker LS2 402. At the start of the season after a couple runs down the local track I noticed blue smoke coming from the car at the end of the run. Pulled off on the return road and looked under the car to see oil pouring out the back of the engine. Still had good oil pressure and temp so drove the car to my Mechanic. He did a leak down test which showed leaking cylinders and so decided to pull the motor. Had a reputable shop completely rebuild the motor .010 over, added custom Nitous Pistons and re-balanced the rotating assembly. Finally got the whole thing back together after weeks of waiting, broke in the motor for 1000 km and headed down to the track tonight. Launched the car pretty good with a 1.54 60 ft N/A on the way to a 11.7 at 113 MPH. I pulled off on the return road just to give everything the once over and I couldn't believe it....oil was pouring out the back of the motor again! I'm at a complete loss...everything is new....how can this be possible? I don't have a catch-can on my set-up but I can't believe that would be enough to cause this and I never had this problem until this year. Any thoughts or suggestions would be greatly appreciated!

S10xGN

iTrader: (11)

Yup, crankcase pressure blowing past the rear main seal. Ask me how I know... Put breathers on the valve covers and call it a day!

nysbadmk8

Bingo! Let the crankcase breath, or install a vacuum pump setup.

KCS

iTrader: (20)

Seriously? Crankcase pressure?

Find out where the leak is coming from first. It may not even be coming from the rear main seal.

Unertl42

iTrader: (63)

I agree find out where the leak is coming from first, but crankcase pressure is quite possibly the cause of his issue. Especially since it only happens when he is at the track

nysbadmk8

Yes, happened to me on my wide ring gapped 403.

Where else is oil going pour out of the back of the motor during accel? Rear cover? would do it all the time. Bottom of the cover where it meets with the oil pan? wouldn't be really affected by high rpm driving, just a slow steady leak..

2000Z28ls1

iTrader: (18)

Does it do it only when beating on it? there is that freeze plug in the back of the crank.

CanadianEh!

iTrader: (4)

We are going to try some different things to vent the Crankcase pressure and see if that nips it. I'll post the results....Thanks again!

nysbadmk8

Start with removing the oil fill cap... if that nips it.. then you know you have crankcase ventilation issue.

KCS

iTrader: (20)

Exactly what I was about to say.

Whatever it is, there's still something wrong. Otherwise just about every LSx engine would need a vac pump, catch can, breathers, etc just to keep oil in the pan and I really don't think that's the case. Correct me if I'm wrong, but there are plenty of 400ci LSx engines out there, gapped for nitrous/boost, that make it down the track without dumping oil all over the return road.