Alternate exhaust valve lifting mechanisms

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Brian Rupnow

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Guys, I need some help here please. I am researching alternate means of opening exhaust valves other than with the traditional 2:1 gear train, and cam. I have so far found only four methods, and I don't know if its only my poor google-foo, or if there simply never were that many in the first place.
I have found the star wheel mechanism, as found on early full size "gearless" hit and miss engines, the weird siamesed cam that flips a lever back and forth, again as found on some early full sized hit and miss engines, the small version adapted by Philip Duclos on his Gearless hit and miss engine (which looks a bit like a metal Swastika) and the strange cam arrangement patented by the Wright brothers of airplane fame. Does anyone know of any other strange exhaust valve opening devices that were totally mechanical and operated successfully to open and close exhaust valves?---Brian
 
The desmodronic valve operation as used by Ducatti is an interesting device. No springs.
Cheers,
Kerry from Oz
 
Hi Brian,

You forgot to mention the double spiral groved crankshaft used in the earley Benz motors.

Kind regards,
Johan.
 
The desmonderic valve requires TWO camshafts. I like the double spiral groove mentioned by Johan, but since I only have a manual lathe and mill, I don't think I could machine that here. I don't really think I could manage to machine sleeve valves either, but thanks for the ideas.
 
Hi Brian,

Sorry for the wrong information. The double spiral groove is not invented by Carl Benz but by his later business partner Gottliep Daimler. A German model engineer Heinz kornmuller offers a casting kit of this engine. The spiral grooves can be made on a milling machine with a Rotary table. Have a further look with Google. Have also a look at this model.
http://serhatece.blogspot.nl/2013/11/daimler-1885-grandfather-clock-engine.html

Kind regards,

Johan.

DaimlerV2.jpg
 
Hi Brian
You should have a look at the St. Marys gearless engine or the Mcvicker gearless engine ,they use exhaust pressure to activate the valve mechanism.
Regards Vince
 

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