Is it possible to lift a head gasket with only 6 psi of boost? Took the head gaskets off car and they looked ok. But they were the graphite gaskets. The middle row of bolts were tight but not as tight as the bottom set. Could have this caused it to lift? The shop that did my head and cam swap does NASCAR motors just wondering if they messed up because everything else looks ok. Had heads checked and they checked out fine. Block was checked also it was fine. Thanks

 

I doubt you were lifting the heads unless you had detonation issues. Why do you think the heads were lifting?

 

that's not enough boost to usually lift the heads... over 15 is more like what it'd take, but there are more variables than just boost to consider

 

It really isn't boost that lifts the heads, it's detonation the causes the problem 99% of the time. There are guys in the LSx world who are runnning way over 30 psi... it's detonation that will kill you!

 

Over heating and severe detonation will lift the heads... boost is not the only factor at play here. If your coolant temps get over 230 degrees on a hot day.... look out for detonation and head lifting.

 

Well the graphite gaskets are not the greatest, but 6#s would not lift the heads by any means.

What makes you think you had head gasket failure?

Were you losing coolant?
Was it overheating?
Did you pressurize the cooling system to see if it lost pressure.


When you take the heads off the car, you can sometimes see a clean spot/area..where the coolant is moving outside of the gaskets (where the seal is broken) across the heads or block.

or

if you do a compression test, if you have two dead cylinders next to each other..this can be an indication of a blow head gasket.

As mentioned above by Highrpm, detonation is the primary factor in head gasket failure...the fact that your boosting magnifies the problem.

I would not worry about running on the hot side with MLS gaskets...up to 230-240...hell the stock fan settings are not until around 230*.

It sounds like the heads were not torqued in the proper sequence.

The stock head bolts are Torque to Yield and are a one time use only...because they stretch to fit.

If you have the heads off this would be a good time to install an ARP head stud kit.

I wouldn't not even expect with 6#s and detonation for the heads to lift.

The good new is....if you had detonation...and the head gaskets failed, your pistons are probably not damaged.

With MLS gaskets..they are so freakin strong..that they will not offer any relief when detonation occurs...so the damage gets pushed to the next weakest link...which in case of the LSx..is the Hyperuetetic Pistons. The ringlands will not withstand much if any detonation at all under boost...and usually more than one piston will crack. Being that you had Graphite gaskets..it sounds like they let loose first...and this probably saved your motor!

So get some MLS gaskets and a better tune. I would check the Compression on each cylinder just to make sure you didn't damage any pistons...you never know with the stock pistons...you might have blown the head gasket(s) and lunched the motor.

 

Thanks I have the heads off now and the pistons look ok. I have been having trouble with a tune also. No one in my area can tune so I went mail order from Ed Wright. I checked timing one time before the heads were off and it was at 32 at 2500, called Ed he told me the mass airflow sensor was bad. He stated he only put 22 cold and 16 warm in it. Said something about oil from the k&n filter got on it and destoryed it. It had a spot on number 7. I have ARP head studs to do the reinstall.

 

Hey man no offense but mail order tuning for FI isn't much better than using a MAFT. It might have worked for some H&C packages 5 years ago, but I would never consider it for a SC package except with a company that has done many SC packages..such as ECS or A&A. They have installed and tuned SC packages on vehicles that you could describe your year car, setup & parts, boost, etc.. and they probably have a tune that is pretty close to dead on.

You still are not at optimum tune with mail order, because every car is a little different. If you do get a tune get one that is on the fat side, that way you add in a margin of error...but the drawback is that it will not be optimized.

I know guys that do data logging on the street, dyno tune, and/or both.

When I first met Charlie (A&As tuner) he used to tune (if I remember correctly) data logging while driving around on the street, and then he started using the dyno..now I think he does both depending on the situation. So I would trust him, if I sent A&A a request for a mail order tune...and as I stated ECS as well.

If you value your investment, don't chance it...just my 2 cents.

 

great I will contact A&A about tuning. I have heard that Ed locks the computer and it will mess up if someone trys to unlock it!

 

Confirm that with Ed - last I heard he was no longer locking the tune.

Mark

 

That is your best bet.

Plus you don't have to worry about whether it is locked or not. Take it out and have the dealership reflash it, or when you send it to A&A (or whomever) they can get that done just as easily.

Locking tunes that takes it back a few years.

If you want some more information on locking tunes and mail order...PM me and I will share all.

 

Had a similar problem, there was coolant leaking out the heads at the exhaust manifolds. All kinds of evil thoughts came to mind.

Upon inspection there was no evidence of leaking on the heads or gaskets.
I have a set of Felbro and APR bolts, the guy doing the work is reputable. I should have never changed the stock gaskets and bolts.

I retorqued the head bolts (myself) and leaks are gone.

There is a good reason why GM uses a yeilded bolts on the heads for permenent installation. They hold stress better over a given strain. It may be that using a conventional bolt requires more torque.

Any way the fact is a properly torqued head started to leak coolent after a month of FI from a roots blower.

 

thats what I should have do but now its too late I took the heads off!