Don Terrill’s Speed-Talk

I would like to see much better view of all the parts and some animations would be nice.

034 bowties on that mule engine...LOL

It take so much power to over come high springs pressures, seems like a great idea if it will stay together at hi RPM. I'd like a better look at that connection between the cam and pushrod.

Mm

Looks much like a Desmo valve train except using the same cam to open and close. TTBOMK, this is not a new design and it would self destruct at high RPM. This type of camming, a captive roller, is much used in industry but not at 10,000 RPM. To hold up reasonably well, the parts must be made very heavy. The F1 pneumatic "springs", obviously, hold up very well at extreme RPM's, and don't need pushrods.

The only thing, in my opinion, that keeps the pushrod engine alive, is the rule books. Kind of like when the AMA required all dirt track bikes to have American made V-twin pushrod engines. How many companies made those?

When the first three 500 cc, single cylinder Hondas were allowed to race against the 750cc Harleys at Ascot, they came in first, second, and third. If that doesn't expose the deficiencies of the push rod engine, nothing does.

The only thing, in my opinion, that keeps the pushrod engine alive, is the rule books.

Yes, agree for race-only applications.

No, for production-based engines, the pushrod V8 engine is still considered the best compromise for space vs. efficiency vs. cost. As much as we obsolete engine guys refuse to run with the trends, we can appreciate what GM and Mopar have done to keep the pushrod V8 competitive in the 21st century.

Maybe, we have to carefully define our terms, just as in the racing series rule books. They're all about leveling the playing field or maintaining the advantage of the group with the most votes; just depends upon whom you ask and which side they're on when.

FWIW, it is reputed some of the most vociferous and bitter internecine rule/class warfare in all of racing goes on among the vintage/classic/X-class in land speed racing. Absolutely no money at stake, most of them race once or twice a year and the fights over the fine points and attempts to get in/rule interpretations to keep out are legendary.

jack vines

I agree 100%, Jack. I'm old enough to remember when Studebaker/Packard made some of the best stuff offered by the industry, especially engine and crank alloys. As did Olds, Ford, and Chrysler with high nickel/tin iron blocks. Also remember Stude using a lock up converter in the 50's, for high gear. (I think it was made by Borg-Warner.)

Also remember Stude using a lock up converter in the 50's, for high gear. (I think it was made by Borg-Warner.)

Yes, Stude used the Borg-Warner DG250 with a lockup converter. FWIW, Packard was the only independent to develop it's own automatic, The Twin-Ultramatic, also with a lockup converter, so Studebaker-Packard was thirty-forty years ahead of everyone else.

jack vines

The valve doesn't know or care where the cam is.

If it ain't broke, why fix it??? I think the current spring valve train system works really good. Also, I don't think they'd be any performance increase with using this system, so why use it? One good thing about the spring is that it's self adjusting. As part wear out, the spring closes the valve all the time. With this springless system, I'd think that as the parts wear out, the valve wouldn't close all the way resulting in worse performance.

But still very innovative. Great to see people trying new solutions to old problems.

dwilliams wrote:The valve doesn't know or care where the cam is.

So you're saying it should just go ahead and work then?
There is to much inherited slop in a captive cam/cam follower set up, it'd be noisy and that tells me it's going to have harmonic issues. Besides the fact the "follower" is side loaded and full of needle bearings that HATE that as much as dirt. Yeash just the new fangled idea to destroy an engine company! Don't take it personally, just me ranting.
In the 90s I worked at a packaging plant and every time an old "cam follower," failed we looked at pnuematics to replace it.

Ducati's been running a similar type of system for years.