Solid Roller Cam ??

[bobcowan]

I was reading the other thread, and didn't want it to get too far off track.

A solid lifter valve train - roller or flat - has lash/slack built in. That prevents the valve from being held open as things change. But too much lash will cause it's own problems. This, I understand.

I thought the specified lash was to allow parts to grow as they got warm. What is valve lash on a hot engine? Isn't it nearly 0"? You wouldn't want it to be zero, I suppose. But wouldn't you want it to be nearly zero? I mean, perfect adjustment would mean that while the engine is at it's hottest - like near the end of a race - it is actually 0". But that would be darned near impossible to achieve in actual practice.

Secondly, concerning spring pressures. Lighter is better. Enough to control the valve train during it's expected use, and no more (theoretically). Any more pressure than is actually needed just wastes energy and wears out parts. Correct? So, how much is enough? Do you just go by what the cam maker recommends? Or is there a magic formula some where?

The bee hive springs intrigue me. I like the idea, and the testing seems to bear out the theory. But I'v only seen them for applications slightly above stock performance levels. I don't see that they're recommended for "big" cams and high rpms. I'v not seen them for a solid roller cam, either.