[YellowRacer]

Originally Posted by Eisernkreuz

Granted, I'm only a Mech/Aero engineering student and hardly an expert on modern engine design, but I'm thinking since the angle of the valves is so close to the perpendicular axis (the direction of piston travel), the forces are low enough that the camshaft bearings and what not, can hold it in place without a high risk of failure. What other forces (other than F=-kx from the spring) does the camshaft have to overcome to open the valve? Some friction, this and that..but because of the relatively small angle, the force in the direction along the camshaft axis is probably something like <5N. What do you think? Even a low force like that repeated back and forth in opposite directions over millions of cycles could be an issue over time? I honestly have no idea..but figure that regular maintenance should be enough to ensure problem-free operation. After all, it's BMW..

I think it all works because of some fairy dust!