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Pistons lost in time


Well Known and Active Website User
VOC Member
Those were the days when 10:1 pistons graced many a Vincent engine
Does anyone stock them now?


Well Known and Active Website User
VOC Member
I use a CP piston that is custom-built for the Ian Hamilton Manx style combustion chamber. It is used by me, David Tompkins, Pete Talabach, and Bill Norton. The static compression ratio is 11.23:1 with my cam and it runs at a dynamic CR of 8.1:1 with my cam. It runs at a dynamic CR of 9.1:1 with a Megacycle Mk2 cam, which is what David Tompkins used to get 10 wins this season.

It requires squish bands to be machined into the heads. The more stock CP pistons that Coventry sells have no squish bands as far as I know. I think Coventry and Neal Videan purchase most of this type of CP piston.

I use CP because the quality is high and they are very consistent. I know that Venolia has a good reputation and makes high expansion pistons, but I do not know much about their current production.


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