If you are looking for brain exercises, this topic can be regarded as being one handed chin-ups.http://www.formula1-dictionary.net/desmodromic.html

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....

Power Robbing Engine Valve Springs | Good Sam Community

15 Replies

MEXICOWANDERER
Explorer
May 22, 2015
Woowee

Rubber cam lobes!

The higher the RPM

The wilder the grind
WILDEBILL308
Explorer II
May 22, 2015
So explain how this is going to improve my mileage and performance in a diesel engine that is governed to 2600 rpm? I do think the electromagnetic valve actuation will end up being the winner because you could program different timing like having a variable cam.
Bill
Chris_Bryant
Explorer II
May 20, 2015
K Charles wrote:
I would bet that electromagnetic valve actuation will end up being the winner.

That's what I would bet- reason being the valve train can be put under direct control of the engine cpu.
fj12ryder
Explorer III
May 20, 2015
What advantage does the hydraulic valve lash mechanism have when referring to the fuel required to open the valves? All the hydraulic valve lash mechanism does is limit the need for manual valve clearance checks. Or were the two questions unrelated?
MEXICOWANDERER
Explorer
May 20, 2015
How much fuel does it require to press open sixteen or thirty-two or however many valve springs per miles of driving? Why not utilize hydraulic valve lash mechanisms? Anyone remember the first modern auto line to incorporate hydraulic lifters? No fair GOOGLING this...
Tom_M1
Explorer
May 20, 2015
Ducati motorcycles have used the desmodromic system for decades.
RJsfishin
Explorer
May 20, 2015
I'm glad their getting it all figured out,..... I am sic and tired of my valves floating all the time !
DrewE
Explorer II
May 20, 2015
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.
WILDEBILL308
Explorer II
May 20, 2015
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
Home_Skillet
Explorer II
May 20, 2015
Valves are so last year.

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