Power Robbing Engine Valve Springs

I would bet that electromagnetic valve actuation will end up being the winner.

A number of years ago 2 individuals, who shall remain nameless, had a bet on whether or not direct hydraulic actuation of the valves with spring return would work or not. The hydraulic pump side was operated by the cam in a GM small block engine. These individual pumps in turn opened the valves through a hydraulic actuator and the valves were returned to the seat with a spring. A SBC engine with the very best of internals available at that time was assembled and set up on the Spintron of the individual who was betting against the hydraulic actuator system. The engine was spun up until the lower end came apart. The story was the engine was some where in excess of 11,000 RPM when it grenaded and no valve float had been experienced. The parts were swept up placed in a trash can and the idea went no further. The design was done just to prove it could be done. I have met both of these individuals and the story has been verified by other people whose veracity I have no reason to question. There are many ideas out there for valve actuation. They all have their pluses and minuses. The Desmo's is maintenance.
Randy

I always thought a rotating ball valve would eventually work out.

A number of years ago my employer tried a hydraulic valve actuation system (among others). While it worked the amount of power needed for the hydraulic pump was more than the power needed to drive a conventional cam and valve train.

Me, after reading the first sentence....

Valves are so last year.


LINK

I am wondering how they keep the adjustment perfect all the time. You would need to be constantly adjusting your lash or the valve wouldn't be closing completely.
Bill

WILDEBILL308 wrote:
I am wondering how they keep the adjustment perfect all the time. You would need to be constantly adjusting your lash or the valve wouldn't be closing completely.
Bill

Wouldn't the combustion chamber pressures to some extent help force the valves closed? The main exception would probably be leakage around the exhaust valve during the intake stroke, and perhaps not even much of that for a turbocharged engine and a cleverly tuned exhaust system.

On some early (four stroke) gas engines, only the exhaust valve was operated via a cam arrangement. The intake valve was just sprung very lightly and negative pressure during the intake stroke pulled the charge into the combustion chamber, while the compression stroke closed it.

I'm glad their getting it all figured out,..... I am sic and tired of my valves floating all the time !

Ducati motorcycles have used the desmodromic system for decades.