[Christ]

Dave -

Part of the reason I don't necessarily agree that the pressure from the springs is returned to the cam is that it's quite easy to turn rotation into reciprocation, but there isn't a direct link to re-exchange the energy from reciprocation (valve closing) to the rotation of the cam. Sure, you're applying pressure from the lifter/rocker against the cam, but alot of energy pushing downward on the cam isn't efficient when you're trying to spin the cam.

I'd be more than happy to review a different opinion, though.