Technical question on the Rotary Engine and high revs

[avsfan733]

Originally Posted by Heeltoe

hmm, then there have to be a total prohibition on turning the crankshaft when the pressurized air is not connected !?
the valves will drop to full valve opening due to nothing pulling up again - daring

ok fair enough....lol....i meant more of there are no coil springs in the formula 1 motors. All the force closing the valves is created by pressurized air in a sealed piston...yes they do leak though making them unsuitable for road cars and often needing topping off it happens rather frequently in the pits and garages if you watch closely

[phoenix]

Positive closing of the valve by the camshaft (desmodromic valve operation) was first used in F1 by Renault, I believe, in their Turbo cars. Then it was done mechanically and the had a very small spring, like you would find on a washing line peg, that held the valve closed. This made for easier starting as, with any cam operated system, there has to be clearance between the valve and the operating mechanism to allow for thermal expansion of the components. This would leave the valve partly open when the engine is not running, even with mechanical closing.

I can see that with pneumatic operation this problem might disappear, but it is likely that some engines are desiged with such a spring to prevent disasterous valve/piston contact and to give decent compression when starting, although turning on the gas bottle prior to starting would, I imagine, have the same effect.