My LT1 is a completely forged 383 with 9:1 compression, single turbo. Everything completely new. My head gaskets are SCE Titan Copper S11066. I can say more about the motor if needed. I finished it up recently and put oil in it. Then the next day or so I noticed oil seeping past my head gaskets and running down the block in a few spots. I was told to run it and let the gaskets work themselves in. Then I fill it up the coolant and handed it over to my tuner for them to dyno tune it.

My tuner calls me up and says that water is getting in the crank case. The dipstick has water on it and looking milky. I personally think the milky color is the white lithium grease from assembly. But it has water on it regardless and showing overfull. They say steam is coming out of my vented catch can (connected to valve covers). Also they said the coolant level kept dropping.

So I believe that the copper gaskets are not sealing worth a damn. I personally clearanced the block myself for the 383. I also did the head porting. I would know if I hit water from grinding... and I didn't. Correct me if I'm wrong, but that only leaves the head gaskets to blame.

What head gasket should I go with that I will not have any water sealing issues? I'm trying to run around 15psi and is street driven. The block isn't o-ringed. The heads and block are machined for copper. I need to stay around the same thickness as these gaskets so I don't throw off my compression ratio.

 

My understanding is that copper gaskets are for o-ringed blocks. I would ditch them and go with MLS.

 

Search me in this forum - Copper and no seal. MLS sealed fine. I'm going back to felpros though.

I've seen people argue both ways. My take is I would never try copper again unless it was with an oring and would expect it to push some water.

 

I'll check it out.

According to their website, the gaskets I'm using do NOT require an o-ringed block or head. So my block is machined right but they still leak.

 

Felpro 1074's.

 

You can try putting sealer around the water ports but odds are they will still leak.

x2 on the felpros. Cheap and very reliable on the street.

 

Yeh I would be too worried that they would still leak if I only put some sealer on them. I might as well replace them with something proven. Those suckers were expensive though.

Are you using the Felpro 1074's on your 383 Jon? Which part number will fit my engine? The only thing I found was PN Z1074 which looks like the bore is to big.

 

You could try some spray Hylomar on both sides and I bet that would work.

 

Hylomar would be a cheap route. Although money isn't really a concern. I would be kicking myself if it didn't fix it and I had to pull the heads again.

I'm just dreading pulling the heads. I spent so much time getting everything perfect and clean. Now I have to yank it back off again. Is it even possible to pull the heads still in the car with head studs? I assembled my heads on the engine stand so I don't know if it's going to be a huge pain in the car.

 

If you have the newer studs with the allen key in them you can pull out the studs in the car which is much easier. I just drop the motor now but understand that isn't the best option for some people.

Didn't look up the part number but if they are the 4.125 bore they are fine.

 

Oh yeh I do have the allen head studs.

Also, how much will my compression ratio change from 0.062 thickness to 0.039?

 

Probably around .3

http://www.csgnetwork.com/compcalc.html

 

I've never pulled the studs out that way though. Seems like it would be pretty tough to get them back in with sealant without making a mess.

 

Yes... 1074's for the LTX

 

Whatever you decide to do with gaskets, consider using the GM tabs they tell you to put in the radiator whenever you do a rebuild. Personally, I use MLS gaskets which a lot of people have had trouble with, but I use the sealing tabs and Hylomar as a coating, and I don't get leaks, and the car runs cool on a hot day, so it's not like that stuff clogs the cooling system. Maybe my methods arent everybody's favorite, but I don't like being the the one who has to take my new engine back apart to fix the coolant leaks. These cars are too hard to work on. One other thing I did was to retorque my heads after the initial run-in and cool down. It's a real pain to do, but I think it's worth it.

As far as the head studs, it might just be a couple of the ones near the rear that you need to take off to remove the heads in the car, but it's been so long since I did that I can't remember exactly.