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Old 04-18-2010, 09:21 AM   #20 (permalink)
dcb
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Quote:
Originally Posted by Christ View Post
...but there isn't a direct link to re-exchange the energy from reciprocation (valve closing) to the rotation of the cam.
All I'm saying is that you can "push" a cam to some degree and get energy return from the springs. when you get towards the base circle of the cam I'm sure it becomes a bit like trying to drive a worm gear in reverse, but not a lot of reciprocating going on there. And when the rpm goes up (and/or you have big clunky valvetrains) the momentum of the reciprocating valve/follower/etc increase and you need sufficient spring tension to hold that mass to the cam under the anticipated operating conditions.

If you are never, never going to exceed 1/2 redline, then maybe you can get away with springs of 1/2 tension. If you lighten the reciprocating components, you can reduce the tension. You also have to pay attention to spring harmonics when designing valve springs FYI
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