Drew03tx

the highest leak percentage was about 20%

Drew03tx

and I've had the correct oil in it with the same problem... any other brilliant solutions?

polyol

Only three ways for oil to get into the cylinder...rings, valves or straight though the intake from blow-by.

Since you ran a leak down I would be checking for excess blow-by. Easy to see.

edmundu

That is pretty high. When I had a similar blue smoke only under WOT and higher rpm's, I performed a leakdown test on a bone cold motor after it had been sitting all winter. And my worst cylinder was 4-5%, and best was 2%. This is on a SBE, with WCCH heads, cam, etc..

In my case it turned out to be the valve guides were out of spec and allowing some oil to pass into the combustion chamber. I replaced the heads, and no more smoke!

Drew03tx

I just had my heads milled by AHP and they also checked the specs on the valves while they had them in their shop. Everything checked out fine.

tomcat11

^^^^What he said^^^^. You can usually listen during the leak down test and hear where the leak is. It helps to use a piece of flexible tubing or hose and holding one end to your ear while you probe the intake, exhaust, and crankcase with the other end. It's a poor mans stethoscope and old racer/mechanic trick. Works to pin point worn out accessory drive bearings too. You could also bolt on a known good cylinder head and repeat the leak down which would help isolate the problem and reduce the amount of work.

As far as the oil goes ya GM has their own agendas and goals to meet.

Drew03tx

since the z06s use a dry sump oil tank what could i use to attach a hose to and listen if air is coming from the crankcase?
?

edmundu

Valley port, or the line coming from both valve covers at the dry sump tank.

tomcat11

You could try the valve covers or the valley port but I think the PCV restrictor in the valley port might prevent hearing the air. Removing the valve covers and listening at the cylinder head drain back holes might work. Now that I think about it capping the valve cover ports might produce some positive crank case pressure which should be noticeable at the valley cover port.

MickVette

My car recently had excessive smoke at WOT:

"During a Corvette Club Cruise one of the members noted that I have excessive smoke from the exhaust at high rpms. That prompted me to do a wiggle test which I could wiggle the valves with the springs still installed. I removed the springs for cyl #2 to get some sort of measurement, mainly because I wanted to use the spring compressor tool I just paid $200.00 for. The measurement at the top of the intake valve was about 0.019" and the exhaust was 0.006". "

Might want to check the valves/guides to make sure they didn't wear prematurely.

https://www.corvetteforum.com/forums...-in-there.html