gasket material for Olds 455 exhaust logs

[broomeju]

I made gaskets from fel-pro 3075 cellulose-rubber gasket material for my old-style, square Hardin water-cooled exhaust manifolds.

they are to seal between the end-caps on the front and the risers in the back.

I figured that these would be hard to find so I made gaskets but then found that for about $60 I could purhcase them.

My thinking is that the water-cooled manifolds aren't going to be hotter than say 200 deg F on average so this gasket material should hold up and the pressures are pretty low across them...

any thoughts? Have others out there gone the cheap route and made their own gaskets and if so what material is best?

[Last Mohican]

Those are usually steel shim gaskets. The exhaust gas going through the middle is HOT. I hope those hold up for you but I doubt they will. For some reason that gasket between the log and the snail is the place people have the hardest time getting to seal.

What you made may be good enough to seal the outside but I would think the exhaust is going to burn that gasket up on the inside. That can lead to water entering the exhaust before the snail. Ultimately you could have reversion issues or even worse hydro lock the motor.

I'm no expert. Hopefully others will chime in.

[ezobens]

I've tried all sorts of gaskets on those square logs and the best I've found so far is the 'Grafoil' type graphite impregnated gasket material. I use the 1/16" thick material and it's great for filling small imperfections and the graphite is rated for temps way above what those manifolds will see.
I use the 1/8" thick material for sealing the logs to the heads (yes, I make my own) and they work great! I believe someone now makes the graphite exhaust manifold gaskets for Olds motors so you don't have to make your own anymore.
Steel shim gaskets rust away in a marine environment so these are the best solution I've found.
The pre-cut gaskets they sell for the Berkeley logs are crap- They don't fit without trimming and in my opinion, don't seal too well either.
Just my 2 cents.
Elm

[Bies]

Stock Exhaust gasket backed with a header gasket, center ports are common, alot of heat. Figured this out on a set of headers.
Metallic side to the head, asbestos gasket torward the manifold. NAPA. My .02

[Last Mohican]

Stock Exhaust gasket backed with a header gasket, center ports are common, alot of heat. Figured this out on a set of headers.
Metallic side to the head, asbestos gasket torward the manifold. NAPA. My .02

Original question was about the gaskets between the log and the snail not the log and the head.

[Bies]

Oh sorry, the grafoil is a great choice. Just make sure surfaces are flat

[Bies]

PS, I have one aluminum Olds manifold if needed.