Bill,
Frankly, I don't remember spending so much time fitting these bolts to earlier projects, but it looked to me like the parts were exactly the same. I don't like grinding away the top cord of the rocker arm, but I was very careful to try and preserve as much strength as possible. The Comet engines have always run to high RPMs without problems.
I have always used the Ian Hamilton designed piston. Carleton Palmer started racing before I did, so I purchased spare pistons from him. He encountered a few problems with the design. He moved the ring lands lower and closer together. He could do this easily with the use of thinner and better rings. Second, he enlarged the valve pockets.
I would have expected that the same could be done easily for other Vincent pistons. I am a little surprised that there is any problem with the valve to piston clearance as the stock pistons are so low in compression. The Hamilton design is 11.23:1 and is quite top-heavy. The pistons tend to scuff as a result. Surprisingly, I have never had a valve touch except when the big end failed.
David
Frankly, I don't remember spending so much time fitting these bolts to earlier projects, but it looked to me like the parts were exactly the same. I don't like grinding away the top cord of the rocker arm, but I was very careful to try and preserve as much strength as possible. The Comet engines have always run to high RPMs without problems.
I have always used the Ian Hamilton designed piston. Carleton Palmer started racing before I did, so I purchased spare pistons from him. He encountered a few problems with the design. He moved the ring lands lower and closer together. He could do this easily with the use of thinner and better rings. Second, he enlarged the valve pockets.
I would have expected that the same could be done easily for other Vincent pistons. I am a little surprised that there is any problem with the valve to piston clearance as the stock pistons are so low in compression. The Hamilton design is 11.23:1 and is quite top-heavy. The pistons tend to scuff as a result. Surprisingly, I have never had a valve touch except when the big end failed.
David