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Discussion Starter #1
How many of you know what a desmodromic valve mechanism is? Ducati's have them. Ever ride a Ducati...very fast! Here is a site on desmo's

http://www.usq.edu.au/users/grantd/mcycle/desmo.htm

I think this was used more in the early 1900's, but Ducati and Mercedes uses them in racing engines. Since the cam and rockers open and CLOSE the valve, more radical cam profiles can be used without resorting to very high rate valve springs. The parasitic losses of this setup must be low too.

I suppose we don't see this more is due to cost, but i'd sure like to see a SBF or BBF with desmo's
 

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Man, us crazy stangers would be GRENADING clutches and trannies with that kind of rpm potential!!
 

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That diagram depicts what looks to be an OverHead Cam design. This set up wouldn't work on a "typical" Ford muscle car engine beause we are, unfortunately, OverHead Valve (OHV) and not OHC.

Betcha it's pricey!!
 

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I don't imagine this would be too difficult with an OHC engine, just a matter of extending the valve stem and connecting it to a cam follower which has a top AND bottom.

I always though it would be interesting to retrofit a "vintage" pushrod engine with a set of roller lifters which would actually be a valve, preloaded with a spring on top to keep it in contact with the camshaft, but instead of a pushrod, to have two oil lines running up the pushrod hole to a plunger to open and close the valve (would mount directly over the valve stem). When the cam is on the base circle, oil pressure would hold the valve shut. On the lobe, oil pressure would open the valve.

Of course, my dream would be to see a direct injected, supercharged two-stroke V8!!
 

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Discussion Starter #6
The ducati was OHC. On a pushrod engine, there would be no way for the valve to follow the cam as it encounters the closing ramp. Using the pushrod design of the SBF / BBF, a second lifter would have to be used to close the valve ( example: the intake lobe is used to open the intake valve and close the exhaust valve and visa versa ), but i'm sure there would be more to it than that and the mechanism and valve timing including overlap would be complicated. Sounds interesting though.

Oh well...guess I'll have to pick up a set of Indy OHC heads from a 60's era Indy Car in AJ Foyts garage...LOL
 

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You can't build a 2 stroke v8 in the sense that we think of a v8... every cylinder has to have its own "section" of the crank case; on older snowmobiles the seal between the (usualy 2) cylinders can rod out and break, causing a loss of compression in the crank case, and the engine will not run.

- Jason
 
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