Engine/Transmission (1994 - 1998) Cometic Gasket or not?

[Blacksdieselhp]

I am doing the head on a 96 215hp truck. I have ordered a Cometic head gasket and have read a lot of good things about them. Read that one guy was doing 80psi on his with studs. But today I found some threads saying that there have been a lot of failures lately out of these gaskets. So shoudl I use it or just go with stock? We are gonna go back with studs. The truck isn't real heavily modded. it just has a 10 plate and he will be doing hybrid 35/40, taper dvs, 3000gsk and a set of 370's.

 

[MMcCallie]

Good question. Talked with Piers just a couple days ago and they said i need to get one. I didn't ask why.

 

[HEMI®Dart]

It's comparing Apples to Oranges...

But with a 440 MoPar, block finish & head finish (RA) value is critical for a Cometic gasket to seal correctly. Somebody said I you run your fingernail over the 2 sealing surfaces & it catches on the finish, they're gonna leak. A few 440 Wedge guys had them leak



From Cometic Gasket:



"A surface finish of 50 RA (roughness average) or finer, is recommended for a proper gasket seal. Anything rougher may conflict with the gasket design. "



Whether the 2 OEM surfaces on the 5. 9 are a 50 RA or finer, I don't know. Maybe this does not even apply to a 5. 9?



Anybody seeing or heard of leaks w/ a Cometic on a 5. 9 with the OEM machined finishes?

 

[Vaughn MacKenzie]

I know Joe Donnelly commented about head & block deck finish using your nail. He said often times your typical machine shop may not be able to finish it that fine.

 

[Blacksdieselhp]

So how smooth do the surfaces have to be. The head was decked and you can feel the lines in it with your nail. What is the best thing to use to smooth it up?

 

[Blacksdieselhp]

Nobody?... ... ...

 

[WrenchRat]

If Cometic says 50 uin RA max, they mean it. Before you attempt to do anything call them and tell them what your situation is. Or try calling Piers. Then you will know EXACTLY how to approach the task. I have ideas, but I'm not gonna guess and lead you astray. Call the EXPERTS.