Copper header gaskets??

[Olden Days]

I just put on some copper header gaskets trying to get a leak fixed (cause thats what they claim to do well) and it leaks worse than the regular header gaskets, but my question is... How do you match the proper gaskets? Do you get the round hole ones to match the header tubes or do you get the square hole ones to match the square ports in the heads??... what I did was get the square ones to match my BB heads but now I am wondering if I should have done it visa versa... anyone ??...

[72shadetree]

on a bb you have oval ports or rectangle ports i know its important on the intake.not sure on the headers but it sounds like you need the headers to match the head to fix your problem.just guessing thou

[70c10]

Olden Days- I need header gaskets also but for a small block and I also need to know if you buy the round to match the header OR the square to match the head????

[FormerMember]

Header gasket shape should match the head. Round for round, etc. Copper gaskets are the best I've used for the money paid.

The flange on the header works to switch port shapes for you and should be fully welded.

[70c10]

Thanks grendel. That's what I thought- to match the head.

[FormerMember]

Originally Posted by Olden Days

I just put on some copper header gaskets trying to get a leak fixed (cause thats what they claim to do well) and it leaks worse than the regular header gaskets, but my question is... How do you match the proper gaskets? Do you get the round hole ones to match the header tubes or do you get the square hole ones to match the square ports in the heads??... what I did was get the square ones to match my BB heads but now I am wondering if I should have done it visa versa... anyone ??...

Here's a question for you. Did you re-tighten after you warmed the motor up?

I use locking header bolts on mine.

Also, if the header flange isn't thich enough, it can warp. If warped, it won't seal.

Some guys will cut the thinner header flange for at each tube so it can "adjust" and seal better.

[Olden Days]

Originally Posted by grendel

Here's a question for you. Did you re-tighten after you warmed the motor up?

I use locking header bolts on mine.

Also, if the header flange isn't thich enough, it can warp. If warped, it won't seal.

Some guys will cut the thinner header flange for at each tube so it can "adjust" and seal better.

Flanges have been cut, I did that before I even installed them. No I didnt re tighten. I never got it hot. I ran it a a few seconds and turned it off and left the shop before I started throwing things. That was the second attempt. I used to have success doubling the header gaskets, so I did that with the regular style first and it helped a little but not enough so I took them out and tried the copper gasket.

[PICKMUP]

Take a slow carefull look at your parts. Put the gasket up to the head and see if it seals the entire port...Now, put the gasket up to the header and see if it seals all the way around.
I normally run the round gasket (copper preferred) that matches the round header flange. It usually will seal all the way around the square exhaust port.
I think you will find that the square gasket will not seal all of the exhaust header.
Let us know what you work out.

[Olden Days]

Originally Posted by PICKMUP

I think you will find that the square gasket will not seal all of the exhaust header.
Let us know what you work out.

per your request.... Heres what I did. I called summit tech line and asked him. he says round gasket. I didnt want to wait so went down town and couldnt find copper but I found regular style round. put them on ... still leaks... call summit again talk to diffent guy ... he says , use square, Huh?.. 2 tech guys 2 different answers. So.. I took headers clear off and measured header flange mating surface, measured head ports. found a MrGasket # that had the same dimentions as the diagonal port measurement (1.92") and ordered them. put them on,... problem solved.
I think it was cause my headers are pretty small tube for a big block and if I had large tube headers it may have sealed with square gaskets. But as the pic shows the square port were not sealing the corners. exspensive lesson but I will not buy header gaskets again without measuing everything real good.

[chevydog66]

I have used both and have had the best luck with Fel-pro header gaskets.

[70rs/ss]

My thought is that you need to match the header to the head, then you will not have leaks. I have the squared ports on my heads and the sqared ports on my hooker comp headers. I noticed that the hedmans had the round, so I sent them back to Summit and ordered the hookers. It looks like they are leaking on the corners of the square gasket, so that makes me think to do it and not have leaks, that you need to match the headers to the head and then the gasket to match the other two.

[Jim_PA]

Originally Posted by chevydog66

I have used both and have had the best luck with Fel-pro header gaskets.

I've never used the copper because the Fel Pro's worked so well for me over the years. Won't consider using anything else.

[409biscayne]

I have never used copper gaskets , i have a dumb question : Do they go on dry , or do you use some sort of sealer ?
Tks ................................ Doug.

[Jim85IROC]

Do you guys think the copper gaskets will work well with stock manifolds too? On my 87 454, I had a nasty leak on the passenger side manifold and had a NAPA replacement gasket put in. It lasted 2 weeks. Now that it's warm I'll do it myself, but I don't want to do this every 2 weeks. So anyway... will a copper work with stock heads and stock manifolds?

[70rs/ss]

If you have a leak with a stock set up, then there is something wrong. The manifold is very ridgid and should not flex, with a stock gasket and the bolts tight (with no cracks in the manifold) there should never be a gasket leak. I'd take it apart and evaluate what you have.

[Jim85IROC]

I plan to, but I've seen many, many exhaust manifold leaks on big blocks, especially in motor homes. They're notorious for it.

[PICKMUP]

Late model BBs incl motor homes ran w/o gaskets. The bolts loosened and manifolds warped or actually blew out areas, like they were torched, if run too long that way.
GM recommends and sells a stainless exh gasket to cure this problem, IF it isn't too bad. Good manifolds can be saved by machining or even belt sanding, if the warpage is minor.