NO valve springs?

[pro70z28]

http://ca.youtube.com/watch?v=GXIdOTkJhEY

[draglist]

Looks interesting. I wonder how much HP is lost on valve springs today and what kind of improvement this could make to Pro Stock and sportsman engines? bp

[Gator]

underhead valves? ( vs. overhead )
.....

Smokey played with this idea.....( many moons ago)

(valve springs) once the engine is running..negligible hp lost ( his conclusion)

[draglist]

Thanks, Gator. bp

[Tom McCrea]

The first item I remember seeing that was designed by Decuir was the TruLink. Looked like a good idea, but I don't know how much it was used.

The springless system looks like it might be ok for drag applications, but I wonder about longevity in road race or NASCAR applications. The pins that ride in the cam lobe grooves surely must take a beating and their size is limited.

The "old" (1896) desomodromic valve train would more reliable IMHO. It has been used by Mercedes Benz in Formula One, Maserati, and Ducati.

[stimpy]

the desmo system is still used in the Ducati motorcycles ,and SAE had an article saying that valve spring systems are basically a low loss system as the pushing open of the valves pressure is negated by the spring pressure pushingthe lifter back down on the return ramp of the cam with equal force on another cylinder . and from the looks of the system too many locking points to fail or needing bearings of some sort . I think the only tru frictionless valve system would have to use hydraulics and servos to open and close the valves.

[Rapid Randy Baker]

Given the choice, I would "AIR OPERATE" them. Unlimited rpm potential, and no friction loss. JMO

[stimpy]

they tried air already but as the rpms rose it would bounce the valves (as air is compressable ) and if you use a compressed intake charge it would push the valves open. IIRC the rpm limit was around 4k