Header gaskets
 

Saw the thread on intake manifold gaskets and thought I would cover the other side of the head. What are you guys using for gaskets when running headers? I am running Lightnings on my engine. Are the copper gaskets worth the money? What about sealant - is anyone using the red high temp RTV on them?

I just use rtv high pressure which is also high temp if you read the tube. No gaskets. But I'm running Stainless Marine Manifolds that have a machine surface. With a header I would use a gasket.

If I can sidetrack this for a second, can anyone tell me the best place to order 525 header gaskets from? I pulled my headers to pressure test and the gaskets are not reusable. Thanks.

The absolute, hands down, best exhaust gasket is a Cometic Multi Layer SS gasket. They are a little pricey, but well worth it. They are basically a lifetime gasket. If/when the header comes loose and starts to leak, a normal gasket will blow out. At that point you need to remove the header to remove all of the gasket, replace it with a new one, and bolt it all back up. With the ML gasket, just tighten up the header and the leak will go away. It's virtually impossible to blow the gasket out. They can be removed as many times as you want and just put them back on. I have some that have been in service for over 8 years now and have been off and on numerous times.

Recently, I had Cometic make a gasket with both the 525 pattern and a standard BB pattern. That saves me from stocking 2 different gaskets. I usually still keep the standard BB gasket since it is cheaper than the dual pattern one. However, the dual pattern gasket is much nicer. It has 5 thick layers of embossed SS. The standard gasket is only 3 layers of embossed SS.

I've attached a pic of the standard BB ML gasket. I have some of the dual pattern gaskets on order. I just sold the last 2 sets last week, so I don't have one to take a pic of. The standard gaskets run around $50 a set and the dual pattern ones for the 525 run around $80. Hell, a stock set of 525 gaskets are almost $60 from Mercury, and anyone with a 525 knows they don't last.
Eddie

x2...

They look expensive!!

SInce they have issues blowing out, do you think some water reversion / ingestion issues stem from this but blamed on a leaking (water internally) header ? Exhaust leaks at the flange gasket have been known to cause reversion.

Why would exhaust gaskets blow out if you make sure the bolts are tight? Mine lasted for years and I had to pry the headers off which tore the gaskets in half. I wonder how much the Cometic ones cost. Guess I'll call around.

I did not know about those gaskets , thanx for the heads up EDDIE!

It's certainly possible. What I meant was that the headers eventually come loose. If you don't catch them in time, the exhaust pressure will push the gasket out. Once it does that, the gasket is junk. You have to continuously check the header bolts, especially if they were recently taken off.

See my post above (#4) for pricing.

The standard ones that I posted the pic of run about $50 and the ones that have both the 525 and standard BB pattern run around $80 per set

purchase through you?

Remflex Gaskets !!!!!!!! THE BEST
They have double the compression than any other gasket NEVER NEVER leak , they make up for uneven surfaces corroded heads or Ex manifolds, reusable, never burn

Scott, I'm still trying to wrap my mind around how a leaking header gasket can contribute to reversion. When the piston is on the up stroke, the gasses take the path of least resistance, with part of the charge exiting through the leak. On the down stroke, if the exhaust valve is off its seat, it is a similar situation - it will try to pull the air in from either the leak or the exhaust primary. If it pulls it in through the leak, it's not going to pull any water in with it, unless the boat is under water. :)

Is it more a matter of less positive impulse through the primary tube into the collector? It just doesn't make sense to me.

If that was for me, then yes you certainly can get them through me.

Here's another one to fry the brain.

Why would a header with too large of a primary ID cause more reversion ?

Thanks. I read too fast and didn't read the last paragraph I guess. Mercury ones are indeed over $31 each through Bam. I found a trusted source for $9 each. :)

Answer a question with a question.. tricky you are.

Not really. Best way to understand something is to think it out, even with help, vs just being told.

So, my question goes into the same sort of reason.

I will contact you soon as I would like to purchase a set.

X2! The Remflex will take up any inconsistencies in the flange (not uncommon with some stainless headers), where the Cometics have very little give, and require a much flatter surface to seal correctly. Because they compress and rebound so much, they don't require retorqueing either.

There are quite a few different thicknesses on the cometics, I don't know if the thicker ones seal any better? The cometic standard bbc, and Merc ones are available through Summit, etc.

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Remflex exhaust gaskets, we used them especially for some of those GIL / Merc alum exhaust manifolds that has flanged warped overtime when the end user does not want to spend the money for new Manifolds or get them shaved. They seal pretty darn well. I like them as well. Their line of gaskets has grown a lot this current year, it seems as it has doubled. .