Just got back from tunning on the dyno, it pulled 375hp and 385tq. But it seemed on the first pull it started to leak a small amount of antifreeze from the heads? I checked it out and found nothing but hints of antifreeze on the rear corners of the block and on the next pulls it seemed to do the same, drip, drip, drip. Do I need to replace the head gaskets, or should wait until it fully cools and retorqe the heads, which would be a pain in the but beacause I will have to remov e the headers.

Next problem, during one of the dyno runs we thought that the wheels spun leading to a sloppy curve, but looking at the rpm where it happened 5000 I think it was ignition. And then on the drive home it seemed that the ignition was iratically braking up and then smoothing out? I have a new MSD opti (LT1 motor), MSD wires, Mallory hyfire CD ignition, and a Mallory promaster coil. I ran a scanner the whole way home and got no codes and no hints of a bad sensor reading? Could it be a bad ground? Maybe the ICM, but I got no code?

 

possible water getting in the combustion chamber. Head gasket trouble tells me to look for detonation in that cylinder.

 

Update, I pulled all of the plugs and all of them out of the right bank are antifreeze green. I guess its time for new head gaskets. I am pushing 12.8:1 compression and just put felpros (FPP-1074 summit#) in 6/2007 with arp head bolts, does anyone have sugestions to a better gasket?

 

why did it blow? detonation? bad tune? Uneven deck surface on heads or block?

 

The cars initial tune was not dead on and ran lean, maxed out my air fuel meter. So I adjusted my AFPR to about 60psi to get the air fuel down around 15 or so and drove it 30 miles to the dyno where it was getting tuned. So I guess it could of been the tune.

Once I got to the dyno I adjusted the fuel pressure back where I wanted it and the tunner did his thing, but on the first pull it stated to leak. I am guessing that the tune was not perfect the first pull.

Has anyone ever waited until the engine fully cooled and then retorqued the heads? Could the head gaskets reseal, I know I should just replace them.

 

Upon the first heat up & cool down of a new build, yes. I always retorque head bolts (studs) with aluminum heads. But since yours has been together for awhile it would be hard to say if it will prove successful for you now. Besides you have to pull quite a few parts off to retorque..at that point you are halfway to pulling the heads for new gaskets. Myself I would change them and then retorque the new ones after the initial warm up.

 

I agree, I am going to replace, but I have never retorqued after intial warm up? That would involve taking alot of parts off as you said.

Two weeks ago was the first time I ever sprayed nitrous, so they could of gone bad then, I just do not know. Either way it is a very slow leak and never saw any smoke out of the tail pipes. And I am hoping the dyno tune that I got yesterday was not affected.

 

get both heads decked if they need it. is this a street motor? you are getting on up there in compression. i hope you are running a pretty big cam with plenty of overlap to bleed off some cylinder pressure down low. (street cruising)

when i install my heads and torque them to spec, i then put a pair of heat guns on it and let it heat for ~20 mins or so. then i re-torque them again. believe it or not, i can usually get another 1/8 turn or so on them.

 

The heads were just ported, polished, decked, 3 angle valve job, and a lot of bowl work two years ago. And the bottom end was just redone last year, that is why the head gaskets were only 1 year old. The cam I am running is an LT4 hot cam (219,228,.525 lift on both with 1.6 rockers and 112 lobe sep) I know its small for a 383, I will go big next year.