OK,

fresh rebuild and using Fel Pro 1074's. I had used them before with no problems on my other 383.

at 200 miles, the pass side started leaking coolant but that eventually plugged up and so didn't worry about it. Now at 600 or so miles, the driver side has started to leak very badly. On top of it, I now have water in the oil.

I checked the torque on a few and they are all within spec (68 ft-lb with moly lube originally on studs).

Before I tear these heads off and replace the gaskets, what do I look for?

Also, suggest a different gasket. I only road race so these 600 miles have all been high load and high rpm stuff.

Thanks,
Ben

 

Well without taking the engine apart maybe you could check the plugs and see if you had any detonation. Something pushed the gasket out, whether it was steam pockets or warped heads or you got bad gas and rattled the engine. I'm assuming you sealed the studs corectly and the surfaces had good prep - the only last thing you could try is to use some GM engine sealling tabs like it says to when you do a rebuild. They stop seepage and I haven't seen them clog the radiator or anything in the few times I used them. I usually use some kind of cooling system sealer when I build an engine and I don't consider it a bandaid.

 

You are correct regarding flat machined heads and very clean surfaces. The studs are sealed correctly and are not leaking (at least on the driver side). I never ran the car above 220 F to keep things like this from happening.

Everyone says NEVER use that sealer stuff but knowing that I have this issue, it may not be a bad time to try it. The alternative is MANY hours of work.

Anyone have opinions on the sealer? I think I will try it.

 

Did you use head studs or bolts? Also, you need thread sealant on both.

 

Studs. I used teflon tape which has worked in the past. However, the leakage is both into the oil AND out between the head and block.

 

What was the surface finish RA put at?

Sounds like a problem with your machine work in that either they did not magnaflux and pressure test properly and something is cracked, or your surface finishes are crap and that's where it's leaking.

 

GM manual says to use it. GM sells the sealer tabs.

Hope your problem isnt worse than a minor leak.

 

Or both?

I will recheck the build sheet but doubt they went into this kind of detail. Honestly I would expect them to do these things since they put about $1K worth of machine work into the block alone. This block was not just washed and put together as a stroker. LOTS of machine work was done to it to improve oiling, screens and magnets installed.

 

All other things being equal, I would bet on the studs leaking. Seen too many threads with the same problem (even from people that thought they had sealed them correctly).

 

We have a weener!

Damn things. I just found the leaks (plural) so now the water in the oil also makes sense. This is my 2nd time trying also. I had to get it up to racing temps and pressure by turning off the fan before the leaks showed up.