The original gaskets were copper sandwich type. My current Koban project has those on it. I have also seen gaskets made out of plain copper sheeting. Considering the low compression ratio, lack of cooling water passages in the cylinder heads, the relative rarity of the engine itself, then factor in that most Kobans won’t typically have to endure endless hours of running time – I don’t see a huge risk in re-using the gaskets, as long as they are in decent shape with no rotted, corroded, or burned-out areas.
If they were a more intricate gasket that had to seal off water passage openings on both the block and cylinder head, it "might" be a different matter – but they don’t, so I don’t worry about it. My success rate for re-using this type of gasket in antique motors is pretty much 100%, both for head and exhaust manifold gaskets. again, overall condition is important, and is why I take great care in disassembling these old relics. Old gaskets don’t wear out, but they can get destroyed when disassembly is taking place.
FWIW – I prefer install the copper sandwich type gaskets dry, without any sealer. That might not be the right way to do it, but I do it that way and it works.
Hope this helps.
Best,
PM T2
PS – Jim, if you’re not going to re-use those head gaskets, feel free to send them to me eh, I love recycling rowboat motor parts.
He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...
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