The Head's are Off and!!!!!
 

4 out of the 8 cylinder's was pushing water?? 2 on each side of the engine.
Either my tune is way off or the head's are not up to the task. I am only at 12lbs of boost also, but I did notice some detonation when I was in myrtle beach. I am sure that isn't helping either.So I guess I will try oringing them first and go from there. I will think about for a couple of day's? I still may go with a different head? I did notice that the head stud's did not seem to be real tight.I never did a retorque since the motor was new, so maybe that was part of the problem.
:jest:

I'd use AFR's, studs, and MLS....and prep the heads for MLS.

Detonation = HUGE pressure spikes. If you actually *heard* the detonation vs seeing it on a scanner it's really bad detonation and means that you are detonating more often than you can tell by ear.

On my car I can't hear any detonation, but the scanner picks it up. Anything over 2 degrees of retard or if the detonation is persistant and I let off the throttle. I pull massive timing at the onset of detonation. Once detonation starts it's VERY difficult to stop it unless you cut the fuel supply. Even if i'm not looking at the scan gage I can usually tell it detonated by the way the car feels due to the amount of timing pulled. I run double the factory attack rate and allow a max of 10 degrees to be pulled.

The detanation was in the higher rpm's and I did get out of it. I was thinking that it maybe was bad gas from myrtle beach. I am not sure about the tune or timing,but something has to change. I know alot of people running stock head's and not having this problem until higher up in the boost range. :drive:

Forget boost, your problem has absolutely nothing to do with boost. It's related soley to cylinder pressure. You can make 1000 hp at 8 psi or 80 psi. If the heads are known to lift at a certain point they will do that when you reach that point. It takes me way more boost to make the same kinda power most guys are making on way less power due to my location and setup.

I'm still running stock ported ls1 heads with mls, studs and 17psi....+700rwhp through a t400....probably on borrowed time but it's lasted 2 years.

I run AFR heads with L19's..

Detonation in the upper RPM band is bad and more so if you hear it. Most of the time if you hear detonation, the damage is already done or at least started. If you are pushing the tune with the limits of pump gas, you are rolling that dice that you do not get a bad batch of gas.

With a new motor, you do need to retorque the head studs after a couple of heat cycles as the directions state. That can be a factor in the heads lifting.

Keith

How do you prep the heads for mls gaskets?

Seems odd with 12lbs... I run the ls6 heads with bolts and push them about 13-15psi and have not had any problems with the gaskets... I've ran over 100passes on these gaskets and no sign of leakage... Kp also has a near identical setup as mine but with afr heads...

What you torque your head bolts down to?

Jay

Hunter, didn't you post that you were running an agressive combo a while back, like a lot of timing? If so, there's your answer. LSx's don't like or need a lot of timing compared to SBC's.

No, the tuner i use told me he hasn't put any timing in it yet.When we was retuning it with the 6 speed is when it started pushing water,and when that happened we stopped there and did nothing else to the tune.he said he had not put any timing in it yet,he was just doing a/f.

I didn't build the engine,but i did not retorque the head's after it was built.That probably did not help any. :drive: