New Copper Head Gaskets - Why You Should Always Anneal Them

New Copper Head Gaskets - Why You Should Always Anneal Them

Anneal Your Copper Head Gasket

 

BSA Copper Head Gasket With Mapp Gas By Bernzomatic

BSA A65 copper head gasket before we annealed it using a Bernzomatic MAPP gas torch.

 

Everyone has there own opinion about when to and how to anneal copper head gaskets or any type of jointing surface that happens to be made of copper. We had an interesting experience here on our personal 1969 BSA A65 that costed us more time than it did money. It involved a copper head gasket that didn't seal properly after we completed our top end job. I'm going to explain my own personal experience to persuade you to always, always, anneal any copper head gasket or copper washers before you install them weather they are new or have been reused.

Triumph T100R Gasket Set

Complete Triumph 500 gasket set without a copper head gasket.

 

Typically when you purchase an engine gasket rebuild kit or top end gasket kit it may include a copper head gasket but many times the head gasket is not included depending on the manufacturer of the kit. From our experience on my BSA, I installed a copper head gasket that was not annealed before we installed it and it started to develop a leak between the cylinder head and the cylinder barrel. I assumed since the copper head gasket was "new", it would have been per-annealed, not so! The BSA A50 / A65 copper head gaskets are very thick to being with, as soon as we removed our cylinder head, we checked the installed copper head gasket. It was so stiff that you could not even bend it. Less than 50 miles and the head had to be removed. This particular copper head gasket was made in the UK. Typically non-annealed copper head gaskets are harder to bend thus causing leaks if you install them "as-is".

 

Triumph 650 Copper Head Gasket Annealed

Triumph 650 copper head gaskets. Top "annealed", bottom "non-annealed".

 

When you anneal copper it expands and becomes soft and pliable thus giving you a seal once the copper has been compressed. I usually use a Bernzomatic MAPP gas torch and heat the entire copper gasket until its "cherry red" then quickly dump it in a bucket of cold water to quench it. If your torch cannot get the entire gasket "cherry red" all at the same time, it will be fine. Just make sure that the copper head gasket at one point reaches it's hottest potential. I do not have the exact temperature in which the copper gasket should be heated to when annealing it. Some manufacturers will not anneal a new copper head gasket when they sell it, but I often wonder why? They may skip out on that step to perhaps save time and money, but in reality, that step is THE most important.

 

 Bernzomatic MAPP Gas Torch Image

MAPP gas torch by Bernzomatic. Can be found at most local hardware or autoparts stores.

 

From here on out I will always anneal any part that is copper that acts as a gasket and I recommend that you do the same. Some copper head gaskets and washers we stock do come annealed and some do not unfortunately. We will usually slip a note in the order reading "must anneal before installation". I hope this post motivates you to anneal those copper head gaskets the next time you install them or re-use them. You can also find a lot more information on the internet forums regarding this heated topic.

3 comments

  • Alex Lee

    Is it reasonable to assume that annealing batches of copper gaskets would add too much cost to the parts? Doesn’t explain why some manufacturers choose to do it though. Perhaps it would make the gasket susceptible to corrosion while in indefinite storage without a protective oil. Very interesting, thanks for posting!

  • Richard Raymond Gilmore

    Brandnew copper gaskets .125 thickness for 5.7 going to annel and install today

  • Peter Akerman

    I had this issue with my 68 A65. I developed an oil leak from around the head gasket after years of pretty steady riding. I first tried to anneal the old gasket and reuse it; from what I understand you can do this a bunch of times. Torqued the head and it leaked right off. I put it up for the season and this year I had the head machined 1/1000 and tried a new gasket which I annealed with a propane torch. Torqued the head to specs and thought I’d have a tight top end. Wrong! it started to leak pretty much right off. I wonder if I did not heat up the gasket enough or maybe my head bolts are stretched beyond reuse. Any suggestions would be welcomed. I’ll try again next spring and maybe the third time is a charm. Thx

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