Desmodromic Valve System…
- Thread starter Exige
- Start date
I remember sort of when down at Sammy Millers Museum he showed off a bike and i can't for the life of me remember what make but it was a mark that pre dated Ducati that used desmodromic, some web searching i think!!??Didn’t realise Ducati copied itI thought it was always attributed to Fabio Taglioni
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Design and history[edit]
Desmodromic poppet valve example.
Fully controlled valve movement was conceived during the earliest days of engine development, but devising a system that worked reliably and was not overly complex took a long time. Desmodromic valve systems are first mentioned in patents in 1896 by Gustav Mees.[citation needed] Austin's marine engine of 1910 produced 300 bhp and was installed in a speedboat called "Irene I"; its all-aluminium, twin-overhead-valve engine had twin magnetos, twin carburetors and desmodromic valves.[3] The 1914 Grand Prix Delage and Nagant (see Pomeroy "Grand Prix Car") used a desmodromic valve system (quite unlike the present day Ducati system).[4]
Azzariti, a short lived Italian manufacturer from 1933 to 1934, produced 173 cc and 348 cc twin-cylinder engines, some of which had desmodromic valve gear, with the valve being closed by a separate camshaft.[5]
The Mercedes-Benz W196 Formula One racing car of 1954–1955, and the Mercedes-Benz 300SLR sports racing car of 1955 both had desmodromic valve actuation.
In 1956, Fabio Taglioni, a Ducati engineer, developed a desmodromic valve system for the Ducati 125 Grand Prix, creating the Ducati 125 Desmo.
He was quoted to say:
The engineers that came after him continued that development, and Ducati held a number of patents relating to desmodromics. Desmodromic valve actuation has been applied to top-of-the-range production Ducati motorcycles since 1968, with the introduction of the "widecase" Mark 3 single cylinders.
In 1959, the Maserati brothers introduced one of their final designs: a desmodromic four-cylinder, 2000cc engine for their last O.S.C.A. Barchetta.
Vincenzo Azzariti
A Brief History of the Italian Marque
Italian engineer Vincenzo Azzariti anticipated Ducati with his desmodromic 173cc OHC single of 1930, developed for Benelli who housed it in a prototype.
This was followed in 1934 by a 348cc bevel-drive DOHC desmo 350 twin with 360 degree crank. This remarkable engine had a bore and stroke of 62 x 57 mm and displaced 344cc.
Sources: Tragatsch p81, desmodromology.nl, MC Storico Conti
But they used it in F1 before Ducati came out with theirs
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Different system to the Ducati mark.But they used it in F1 before Ducati came out with theirs
Both Desmodromic Systems - one copied from the other: no different to the Z1 Kawasaki Engine and Suzuki copying the layout and design principle for the GS750
Subtle differencesBoth Desmodromic Systems - one copied from the other: no different to the Z1 Kawasaki Engine and Suzuki copying the layout and design principle for the GS750
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Duke of Prunes
Well-known member
Ducati never claimed to have invented desmo valves ......
..... but they have always been perfectly happy if people want to believe it .....
I looked into this years ago and I came across an interview with Lee Iacocca ,
who had been part of Ford's racing team ( he ended up as CEO of Chrysler ) .
They were astonished by how fast Mercedes could rev their engines , and at one race meeting
they decided to sneak into the Mercedes garage at night , for a bit of " investigation " .
Of course , one man's "sneak" is another man's breaking and entering .... but hey ho !
Interesting bloke Iacocca -
en.wikipedia.org
..... but they have always been perfectly happy if people want to believe it .....
I looked into this years ago and I came across an interview with Lee Iacocca ,
who had been part of Ford's racing team ( he ended up as CEO of Chrysler ) .
They were astonished by how fast Mercedes could rev their engines , and at one race meeting
they decided to sneak into the Mercedes garage at night , for a bit of " investigation " .
Of course , one man's "sneak" is another man's breaking and entering .... but hey ho !
Interesting bloke Iacocca -
Lee Iacocca - Wikipedia
sev
Elite Member
fo sho bredrin. In fact right up to late last century a lot of race engines were still running spring inside a spring. I know the 500GP engines certainly did for a whileSprings were only good for zebedee back then
Dukedesmo
Active member
My GPz engine does too - didn't most bikes back then
My old Guzzi has double springs on the valves - didn't stop the piston hitting the exhaust valves though...