Head gasket, copper vs composite vs...

Has anyone ever tried aluminum head gasket on his Norton?

Saying that because I just tried on my beemer for 10.000 miles without any leak. And will reuse them without the need to anneal them.

I didn't realize anybody offered AL head gaskets. Normally you see sheet steel, multi-layer steel (MLS), copper, or composite. I know that BMW uses AL cylinder base gaskets in some (all of ?) their boxer motors but I wasn't aware they used AL head gaskets. Of course, if BMW uses AL head gaskets, obviously they must work in BMW's application. Whether they would work successfully on a Norton, I have no idea. Frankly, I would just go with the "KNOWN" and use a standard head gasket from any of the usual suspects among Norton suppliers. I prefer composite (MLS, if available for a Norton is huge overkill) but copper is good IF you spray both sides of the new gasket with aluminum paint. Otherwise, copper tends to weep at coolant or oil passages. The AL spray paint thing on the copper has been common at least since the 60's, maybe long before. Some folks use silver paint and claim that works but I have only used AL for more years than I care to remember and have no experience with silver paint. I suppose the metal particles in ether paint could do the necessary job.

I guess that's a long non-answer to your question. The proper answer is: I have never tried an AL head gasket on a Norton!

You used to be able to buy thicker aluminium head gaskets to drop the compression slightly. I tried one but it oozed like putty into the pushrod tunnels and got as far as touching the pushrods. I've used the composite ones since without problem. I think they are better than the solid copper.

Ian

MexicoMike said:

I know that BMW uses AL cylinder base gaskets in some (all of ?) their boxer motors but I wasn't aware they used AL head gaskets.

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The standard BMW head gaskets of that type are composite.

The Norton factory did try aluminium head gaskets but it appears they were not very successful according to the NOC Service Notes.

MexicoMike said:

I know that BMW uses AL cylinder base gaskets in some (all of ?) their boxer motors but I wasn't aware they used AL head gaskets.

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L.A.B. said:

The standard BMW head gaskets of that type are composite.

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You are both right, it's possible to put Al base gaskets on some airheads BMW and stock head gaskets of those years bikes are composite.

I was jus wondering if AL head gasket were already tried on Nortons, because on a street bikes I don't understand why putting a copper one. It's soft and we all know that under pressure and heat the molecules will move. So it's finally normal to have leaks and retorquing needs. One a racing bike it's different of course.

Nortoniggy said:

I tried one but it oozed like putty into the pushrod tunnels and got as far as touching the pushrods.
Ian

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L.A.B. do you remember when was that first try of AL head gaskets? Could the experience be stopped because of bad or wrong choice of the AL? Or just because it was heating too much?

Saying that because my beemer is slightly compressed (16psi) and the oil in the sump heats up to 280°F in cities.

My Dad replaced the copper head gasket on my Yamaha dirt bike with aluminum foil when we rebuilt it. Different application,(no oil) but, it is done.

NKN said:

L.A.B. do you remember when was that first try of AL head gaskets? Could the experience be stopped because of bad or wrong choice of the AL? Or just because it was heating too much?

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I don't know. According to Norton Service Bulletin N3/68, Sept. '73 the thick 0.080" alloy gasket was originally available under part number 064072.

I believe 0.080" aluminium gaskets were used to 'detune' the stock of unsold Combats (and replacing the Combat camshafts with standard) sometime around mid-'72.

The NOC Service Notes advises against using aluminium gaskets because they squeeze out and spread into the pushrod tunnels, as Nortoniggy described.

OK, thanks L.A.B.

I bought a 1972 combat new in May of 1973. It had the thick aluminum head gasket in it. I presume it was changed by the dealer prior to sale. It blew a piece of aluminum out between the two side head bolts while cruising at 70 mph at approximately 1500 miles.