Copper Head Gasket

comnoz · Jan 21, 2011

The annealing takes place just by heating. Quenching it in cold water simply helps remove the slag from heating. I generally remove the rest of the slag with a wire brush. Then it's ready to install. A little sealant of your choice around the pushrod and oil return holes is all that is needed. Dental floss seems to help a little. Sealant doesn't do any good to seal the compression.

37 years now and never blown a head gasket but I have fixed a few for other people.

Keep your head bolts tight. Jim 8)

lcrken · Jan 21, 2011

splatt said:
Buy a modern auto gasket for a cast iron block alloy head engine, the good ones are graphite based, to allow for the different expansion rates, and they nearly all have a bead of sealant built into them around water/oilways. The technology being used to make norton gaskets could easily be improved, with out the need for machining oring or fitting dental floss .....

IIRC, Kenny Dreer had some head gaskets made for his 880 kits that were a combination of metal and graphite, but I've not seen one, so can't provide a description. Sounded like a good idea to me, expecially for the big bore conversions. I never pursued it, but maybe someone like CNW would consider having some made.

Ken

splatt · Jan 21, 2011

lcrken said:
[IIRC, Kenny Dreer had some head gaskets made for his 880 kits that were a combination of metal and graphite, but I've not seen one, so can't provide a description. Sounded like a good idea to me, expecially for the big bore conversions. I never pursued it, but maybe someone like CNW would consider having some made.

Ken

The cost of getting special gaskets has come down and the quality has improved dramaticly, they can be lazer cnc profiled so they are very accurate, prehaps FULLAUTO could approach ACL in Australia and see if they could produce a more advanced gasket :?: :?:
Reading through this thread it seems like oil weeps are common,I previously asked if the thru bolts could leak but it now seems more likly to be weeping out the push rod tunnels.

Carbonfibre · Jan 21, 2011

Firstly new copper gaskets do not need to be annealed. Forced induction drag race motors often used copper gaskets, but in many cases cylinders also had Wills rings fitted, and faces adjacent to oil ways were sealed with Hylomar. However high spec crom-moly cylinder studs were also used, and probably a good idea to use compound type gaskets if you are not wanting to replace OE fastenings.

Cheesy · Jan 21, 2011

Carbonfibre said:
Firstly new copper gaskets do not need to be annealed. Forced induction drag race motors often used copper gaskets, but in many cases cylinders also had Wills rings fitted, and faces adjacent to oil ways were sealed with Hylomar. However high spec crom-moly cylinder studs were also used, and probably a good idea to use compound type gaskets if you are not wanting to replace OE fastenings.

What are the benefits of the cromoly studs? They all have the same modulus so Im guessing that they are torqued higher (70% of yield kind of thing) than a lower grade stud. In fact there are more than a few engines that havent worked so well when original fasteners have been replaced with larger stronger ones, even though that sounds counter intuitive.

Back to Commandos though, is there a significant difference in oil leaks/blown gaskets between the 750 and 850 engine, I ask this as Im under the impression that the 850 has studs that go right to the cases ie much longer. This has quite a significant effect on how the bolted joint actually works.

comnoz · Jan 21, 2011

Carbonfibre said:
Firstly new copper gaskets do not need to be annealed. Forced induction drag race motors often used copper gaskets, but in many cases cylinders also had Wills rings fitted, and faces adjacent to oil ways were sealed with Hylomar. However high spec crom-moly cylinder studs were also used, and probably a good idea to use compound type gaskets if you are not wanting to replace OE fastenings.

New copper gaskets probably don't need annealing before use, however if the gasket has been laying on somebody's shelf for who knows how long it should be annealed before use.

quote from > Metals and Hardening <

" Properly annealed copper wire can become harder during storage due to precipitation hardening. This effect will increase with increasing temperature - i.e. in the sun versus a cool spot."

Jim

Carbonfibre · Jan 22, 2011

Anyone who is not building a race motor which will be stripped on a regular basis, and who does not want to replace OE fasteners, would probably be better off using a compound gasket, or better still a modern shim type gasket, which is superior to either copper or compound.

bmwbob · Jan 22, 2011

illf8ed said:
bmwbob said:

Maybe we should have a poll of how many have succeed in using copper head gaskets and keeping them oil tight VS going with flame ring and the occasional blown head gasket (2 in 20 years for me) :?

Click to expand...

Hi Bob,

Flame ring for me for the last 30 years with not one failure on '72 and '73 750 engines.

I've had two fail in twenty years. Even after proper re torquing procedures. But better than oiling up the whole side of the bike! :wink:

mikie3117 · Jan 23, 2011

Hello to all. I use copper gaskets. I get em cherry red on the gas stove top, quench em and then spray them with copper coat the night before install. Seems to work for me but I also keep compression and revs down low.
Mike

pommie john · Jan 23, 2011

I use a copper head gasket on my 750 racer. Admittedly it doesn't do high mileage but it does get a fair bit of abuse, running to the red line at most gear shifts.

I heat it red hot on the gas stove with a propane torch at the same time. I can't get it all red hot at the same time but it doesn't seem to matter. Then I quench it to get the slag off, clean it with medium grit emery paper, and finally spray it with a coat of silver paint ( just standard rattle can auto silver paint).

This seems to work fine.

One thing though. I took the head and made sure it was flat by taping a sheet of emery paper to a mirror and lapping the head until it was perfectly flat.

xbacksideslider · Jan 24, 2011

Seems like Cometic could whip up some multi layer stainless steel gaskets; they coat each side of each piece of the sandwich wiith Viton. They seem to be indestructible in high boost turbo applications. One downside is that they callout extremely smooth head/block surface specifications.

Hobot · Jan 24, 2011

This is educational comprehensive head gasket article, except for the part about 3 hp per cubic inch engines, unless of course our old stuff flops around as much on 1/3 the power pressure.

http://www.enginebuildermag.com/Article ... skets.aspx

Copper Head Gasket

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