Best Copper Gasket Sealant?

aries · May 19, 2010

Hi All
Recently had both the cylinder head and barrel skimmed on my combat 750 commando. Consequently Iv opted to use a copper head gasket. Now then, which sealent would be best cos Im weary of leaks!!
Have searched the forums and sure, everyone has a preferance right down to silver paint spray on the gasket. Here in the UK cant find the Permatex copper spray but have a tube of "Permatex Ultra Copper gasket maker", also "Pro Seal RTV Copper XS silicone", "Loctite 5920 Copper Silicone". "Wellseal" and finally "Yamabond". Think I prefer the idea of the last two products as its more of a liquid application. But Im just not sure.
Your thoughts and feedback would be much appreciated as to the best product for purpose.

rvich · May 19, 2010

I would look for a copper sealant in a spray can. it allows you to spray it on in a nice even coat and set to tack before install.
This way there is no goo to squeeze out into spaces where it is not wanted.
Russ

highdesert · May 19, 2010

Tried a copper head gasket years ago and just could make it stop leaking.
Just curious as to why a traditional flame ring gasket removed from your list?

BrianK · May 19, 2010

I'm a big fan of Yamabond (and its other-brand) equivalents but when I replaced mine recently, I used the copper spray on a flame ring and liked the results. So far, so good (only 600 miles and a half dozen - yes, I'm anal! -retorquings so far).

PS, Jim Schmidt recommends a bit of silicone adhesive and a bit of thread looped around the pushrod tunnels and oil return holes (watch his Norton parts video) for curing leaks from copper gaskets. No experience with this myself, but Jim's a pretty knowledgeable guy.

pommie john · May 19, 2010

I use a copper head gasket on my 750 racer. I'd always had trouble with it leaking until someone told me to try ....silver paint! Yep, ordinary spray can silver. Spray a thin coat on the gasket, let it dry and bolt it all together.
It never leaks now.

bmwbob · May 19, 2010

Read an advisory to use a light coat of ATV around the rear oil passage and push rod tunnels then embed a length of thread in RTV and light coat over top of thread. Never tried it, but sounds feasible. There's a YouTube video with a guy who makes pistons and rods for Norton's explaining it.

Danno · May 20, 2010

Permatex Copper-Coat. It's a high-temp spray-on with powdered copper in the mix. Same application as silver spray paint (which contains aluminum powder)

aries · May 20, 2010

highdesert said:
Tried a copper head gasket years ago and just could make it stop leaking.
Just curious as to why a traditional flame ring gasket removed from your list?

Hi
I would prefer to use a flame ring gasket, but right or wrong, having had a total of 6 thou inch skimmed in total felt I needed to raise it up a bit ?? Just not sure whether flame ring would survive with slightly higher compression ratio?? Would like to get some more feedback on that one please.

highdesert · May 20, 2010

I am rebuilding my motor now, and am raising the compression from stock by taking some 50 thou off the head.

I will be using a standard flame ring head gasket. No way will I ever use copper again.

Seeley920 · May 20, 2010

I use copper on both my race motors. Anneal it properly and it shouldn't leak. Apparently Permatex copper form a gasket is no longer available in the UK. I did have a supplier, but he can't get it any more.

aries · May 20, 2010

Mmm, Thanks for the feedack so far. Right ole headache for options really thus far. Though am tempted to try the copper gasket with a bit of Yamabond??. I did try copper many years ago, and yes, it leaked like a sieve, minus any sealant though.
50 thou seems a lot of skimming, not that Im mechanically knowledgable of such things. But you have swayed me towards the flame ring again.

jseng1 · May 20, 2010

The problem is oil leaks - not compression leaks. Flame ring gaskets can eventually blow out. Plain old contact cement (Barge at OSH or automotive gasket types etc) seems to work the best. But you have to use thread around the pushrod tunnels and oil return hole. My instructions recommend your favourite sealer but it is the thread that provides the seal. 30 weight Silk thread works the best but its hard to find (go on line).

Currently I am using only a .003" thick narrow copper ring around the bores. Only contact cement and 30 weight silk string around the pushrod tunnels and oil return hole. Works perfectly and you don't have to re-anneal it each time you remove the head - just glue it to the cylinders only and leave it glued on forever.

Available at my website:
http://users.gotsky.com/jimschmidt/nortonrods.html

I discovered contact cement when I was gluing the gasket to the head with a couple small spots (for easy installation) and later found that the glue was holding up to heat & abuse.

Lacquer thinner and Q tips is the trick for removing dried contact cement.

Jim Schmidt

PS
Ron Wood recommends contact cement for his copper head gaskets.

rvich · May 20, 2010

Re silk thread...you might try a fly fishing shop. Silk would be very traditional for the craft of tying flies and building rods...I bet there are shops that cater to the traditionalist in the UK.

Flo · May 20, 2010

Used to use copper head gaskets a lot, but tend to use composite ones now.
I have never ever used anything on head gaskets, just degreased it all with thinners first.
The key to success is engineering, not chemicals. Lap the head onto the barrels with grinding paste, this is the only way the surfaces will be flat with each other.

Foxy · May 20, 2010

In an early post someone mentioned using a dremel or scribe to make a groove around rod tunnels etc on copper gaskets, then use your favourite sealant in this area. The groove and and extra sealant makes an Oring.
Foxy

ML · May 20, 2010

highdesert said:
I am rebuilding my motor now, and am raising the compression from stock by taking some 50 thou off the head.

I will be using a standard flame ring head gasket. No way will I ever use copper again.

Will you be shortening the pushrods? - Rocker geometry gets out when you skim to Combat or further on the head.

Mick

SGOUD · May 20, 2010

Danno said:
Permatex Copper-Coat. It's a high-temp spray-on with powdered copper in the mix. Same application as silver spray paint (which contains aluminum powder)

Do you apply the sealant on both sides of the copper gasket???

aries · May 21, 2010

If I could get hold of a can of copper spray, Id give that technique a shot. But here in good ole blighty I cant find such, only the tube options,or the more liquid Yamabond etc etc.
Silver paint spray appeals to try and yes I believe both sides of the gasket are covered.
Certainly some thought provoking and imaginative solutions put forward. Thanks for those thoughts and ideas.
Im just gona have to sit longer in the garage and ponder which way to go.

BrianK · May 21, 2010

[/quote]Do you apply the sealant on both sides of the copper gasket???[/quote]

Just the side(s) you don't want to leak.

Sorry, couldn't resist....

pommie john · May 22, 2010

As Seeley 920 mentioned, the copper gasket must be annealed before use. When you buy it from the shop it is not ready to use.
To anneal it, it needs to be heated uo to red hot and then cooled rapidly in cold water. It can be done on a gas cooker. It's not essential that the whole gasket is done at once, it can be done in sections becasue it's hard to get the whole gasket red hot at once.
I do it in three or four sections.

Best Copper Gasket Sealant?

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