Heads were pressure checked before this install, no leaks on the other motor they were on, bjuice. Maybe I'll get lucky and it will be something else. I'm probably overdue for a block problem, as I've run em at .060 and never had a problem. :lol:

I believe I'm gonna get lucky. Pulled the heads, cylinders are beautiful. Looks like the problem is gonna be in the seat of the # 4 exhaust valve. :shock:

.060 over on a GM 400 is a disaster waiting to happen ! I ran GM 400 for years and when .030 got loose i got another block. Never blew one up!

:? Well, the head checked out OK. Pressure checked OK. Checked for warpage, OK. Block looks perfect also. Any ideas?

when you said the head checked out ok..what was done to check the head...was the vales taken out and bowls,etc checked.. ? Mine also checked good on the initial rounds of pressure checks but after much closer with the inspection ( with dish washing liquid) we saw the tiny bubbles coming from the crack in the bowl itself.
it was seeping so slowly that it would pass the Pressure checks.... bit would eventully seep enough water into the cylinder once the head got hot........if your heads have had any port work at all i would start where the work was done..

One thing for sure its soming from the heads or the block ..lol :D :D ..

i would really look close at my heads before i got into the block...

Terry my hairline crack was so small it was almost undectectable.

just telling you how i would handle if it were my motor.

hope you find it.

also what brought you to conclusion the problem was in the exhaust seat valve #4 ?


thanks brian

Yep, the valves were removed, my head guy waited to reassemble them after I looked at em. The reason I thought it was the #4 exhaust port was water stains in the port going out to the header. I believe now that the valve was open, and the water was backed up past the valve. Good ring seal. :lol: The shop I use is a locally known shop and one of the areas best tuners is next door. The engine builder at the shop and the tuner guy in separate conversations said it was probably a gasket sealing issue and told me the method they used, practically identical. A thorough search of the block once more and swapping the heads from side to side is next.

You need to pressure check those heads in hot water, have seen the presure test fine till up to temp. Good luck though hope it is a gasket problem.

Yeah, good suggestion. However, this leak was while it was sitting on the trailer so I'm hoping I'm good. Finally got my head gaskets yesterday, what i get for buying local. Maybe in a week or so i'll have it back up. Thanks.

Well, my buddy and I triple checked everything and put it back rogether today. Brought the engine home and started getting it ready to drop back in. When I get an extra set of hands I'll get it in and we'll see.