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Discussion Starter · #1 ·
This is not directly impala content (But once I get my car done, I can start the work on my dads 94 SS). I am finishing a motor buildup for my 88 Monte SS. Its a .030 350, ported iron heads, healthy cam, etc. But I want to install thin head gaskets to bump the compression up. They are .015" vs .039". The P/N is 1094 and they are made by Felpro. The question I have is do I install these bare? Or do I put some type of sealer on them? I have gotten all different answers. Both surfaces are flat but I don't want to have leaking head gaskets right off the bat. Any help is appreciated.

Thanks
Nick
 
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Discussion Starter · #2 ·
Why don't you mill the heads the necessary amount and use a thicker gasket? Seems like that would be a more reliable thing to do. I know it costs more now, but I think it would save money in the long run...
 
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Discussion Starter · #3 ·
I take it that the .015 gasket is a steel shim gasket? When I built my motor, I went with a copper gasket an o-ringed the block. I followed their instructions to a T, used the expensive Hylomar sealant, measured my surface finish in microinches, etc, and I had all kinds of problems. The motor would run fine, but when shut off and after cool down, it would leak water into the cylinder bores from the water jacket (very hard to detect this by the way; It just acts like fouled spark plugs; I ended up replacing the optispark, wires, plugs - had nothing to do with it). Once I figured out that water was getting into the cylinders on shut down, I called the gasket maufacturer and spoke to their design engineers, blah, blah, blah. They all said the same thing: I didn't get the surface finish just right, heads weren't exactly flat enough, etc, etc and that I would have to pull the motor apart. I eventually spoke to a guy who has done a lot of motors with copper gaskets. First thing he asked me, "Did you try putting in any block sealer"? I hadn't tried that, but I figured what the heck. When motors first fire up after a rebuild, it is common for them to weep a little water until the water jacket/gasket/head junction corrodes to together a bit. I made the mistake of firing up the motor with antifreeze instead of just pure water. The antifreeze has so much anticorrosion additive that it won't alow the head/block/gasket to corrode any. So, after 2-3 days, the Hylomar began to give way. Ideally, the corrosion factor takes over as the Hylomar breaks down. Eventually, the water leaks got so bad that you could actually see water shoot up into the valve cover area (took them off just to take a look) when the motor was shut down. The water would spray up the bolt holes into the top of the head. The head bolts were siliconed into the motor and that's not where the leak was coming from.

Anyway, to make a long story short. I put K&W block sealer in with just regular water and the leaks sealed up in less than 1 day.

Moral of the story: follow the gasket manufacturers instructions, use as much head gasket sealer as you like (it will go away eventually anyway), make sure the surfaces are as flat as you can get them, run just pure water for a day or so to allow the joints to seal a bit on their own, use block sealer like GM does to insure that you have no problems.
 
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Discussion Starter · #5 ·
I couldn't agree with Stonebreaker more!

383SS is also dead right but it sounds as if he has a totally different reason and set-up for running shim-gaskets and o- fire- rings than you (you aren't running o-rings, right?).

Also, shoot Fel-Pro an email and see what they have to say. They didn't get to be Fel-Pro by not knowing what they are doing or having lousy customer service. In general, they genuinely care and are interrested in what guys are doing with their products.

What does your machinist reccomend?
 
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Discussion Starter · #6 ·
Thanks for the info. I contacted Fel-Pro but they haven't gotten back to me yet. My machinest finally got back to me and he said w/ 64cc heads and standard head gaskets, my compression should be like 9-1 to 9.3-1. Thats fine for now. I asked him about the steel shim gaskets and he said he'd rather see me using the standard one. He has seen the steel shim gaskets leak too many times and he would only use them on a motor that was goign to get torn down after each season. I have to agree with him, there is nothing to those gaskets. Just metal. I'd rather loose a little compression then have the dam gaskets leak.

Thanks
Nick
 
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