BSA C15S COPER HEAD GASKET

[bobby12]

Hi
Been reading some reviews who state that the copper head gasket should be annealed before fitting, heated until red and left to cool !!
Is this correct ?
Thanks,

[Spaceman]

Yes - in order to soften the copper. I normally heat to red and then quickly quench but, for reasons I don't understand, you can achieve the same result by simply leaving to cool slowly.

[idie]

Quick quenching is to stop the formation of scale that can sometime occur.

[bobby12]

Hi
Thanks, just wondering now if, as the copper gasket is new was it already annealed before the previous owner fitted it as I have stripped the engine down to check all is well, the engine has not run and the gasket is all new and shinny, any way I can check ?
Thanks,

[idie]

I would aneal the gasket before reusing as they can work harden. Not worth the risk.

[Spaceman]

As said, best to anneal to be sure. Unless the sheet of copper was annealed before or after the gasket was cut from it, which is unlikely, it would have become work hardened from the rolling process used to form the sheets.

[bobby12]

Hi
Might seem a silly question but do the copper oil feed pipe washers also need to be annealed or is the manufacturing process different and they are ok.

[idie]

They get work hardened when stamped. It would be a good idea.

[Spaceman]

Hi
Might seem a silly question but do the copper oil feed pipe washers also need to be annealed or is the manufacturing process different and they are ok.

With copper, it's always safer to anneal - it's such an easy process to do that there is no reason not to do it.

That said, modern bikes tend to use Aluminium sealing washers and, although you should anneal them before reuse, it's very difficult to do because there is no colour indication when they get to the correct annealing temperature. I am definitely guilty of not annealing aluminium sump plug washers before reuse or using new ones but, despite this, I have never had a problem with leaking.

[DAVE BRADY]

Hi,

For aluminium try rubbing some soap on it and heating up until the soap goes black.  The aluminium will be soft enough to bend so should be soft enough to crush when tightened up.  I used his technique to alter the bend on BMX handle bars and it worked.  However once cooled down the aluminium returned to how it had been before so it would have to be assembled whilst still quite warm.
Perhaps there are different levels of purity of aluminium or alloys used for different purposes so a type that stays soft is used for sealing washers?

Dave.

[Spaceman]

In contrast to copper, I think annealing aluminium depends on what alloy it is with each having its own annealing requirements in terms of heat treatment duration and temperature. In terms of aluminium sealing washers, it therefore probably does come down to using either a new washer or simply re-using the old one as is!