Rotary valved engines

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Post by Mook » Fri Nov 17, 2006 2:45 pm

Rotary Valves, How neat. One of my hobbies is racing go karts. No, not the yard karts that everyone (or almost everyone) had when they were kids. These are a bit different. Anyway...... Back to the subject.

Rotaries were "The thing" a while in the 100cc 2 cycle karting engine world or road racing.

There were several manufactuers that did quite well with them. Hewland Arrow, TKM, DAP, PCR, Parilla and seval others. The Italian engines seedm to be the best interms of power to weight and reliability. Not to mention that they would rev into the 15k range quite easily.

The reason I mention this, is that if you can look at some of these examples as reference while in the conceptual stage you could perhaps mix and match and come up with an engine that is truly cutting edge along with being a labor of love.
It's important to keep the main thing, the main thing.

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Post by SamD » Sun Dec 03, 2006 8:36 pm

Rotary valve engines have been in use for over 100 years. If you can find a way to do them dry you are making a huge improvement, although personally i think the oil consumprion difficuklties were highly exaggerated.

i suspect that teh car makers aren't real interested because thay want to get away from recips entirely.


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Re: production rotaries

Post by magic9r » Sat Mar 03, 2007 11:29 pm

swarfed wrote:Are there no snowmobilers here? Skidoo (Bombardier) has been using rotary valved engines in their sleds for a few years now. I think their watercraft may have them too. They're not spherical rotaries like the Coates engine, but they're a production rotary engine nonetheless. And I suspect their valve system would be much easier to duplicate than the Coates.
a Skidoo Bombardier with a Rotax engine, is that what you were referrring to?
Rotax make no mention of rotary valves on their site, do you have model details?
I'd like to take a look at these as I've just ridden one in Tahoe this week,

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Post by Spin Doctor » Sun Mar 18, 2007 7:55 am

For any IC engine the future if it still exists 20 years from now is IMO one that employs electro pnuematic poppet valves. While a rotary or sleeve valve for that matter can be much more precisely controlled in terms of the opening and closing events the duration is fixed. With the afore mentioned E-P poppet valves they could be programed to run at various setting and even disabling any of the valves depending on conditions. That said a rotary or sleeve valve model engine is just plain neat.
I don't know everything, just enough to be dangerous

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Rotary valves

Post by Junkman » Wed Aug 22, 2007 4:54 am

Rotary valves have been used in many production engines especially motorcycle engines, Rotax,Puch and others, all of them finally gave up.
You might want to look into this for some answers. If you are eliminating the valves why not just go 2 stroke? Good luck. ... alveIC.htm

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Post by kovacjr » Tue Sep 18, 2007 7:17 pm

Another engine manufacturer that uses power valves is Ducati motorcycles. They have a mechanically powered valve both directions. They get up there in RPM also but no where 18,000 like a rotary

Also check out this bike builder that is going for a patent

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Post by zeusrekning » Fri Jan 18, 2008 6:21 pm

I'm also working on a rotary valve design. Mine is more similar to the Aspin rotary valve style. My belief is that the only drawbacks to rotary valves are friction and sealing. I believe that with current technologies and materials it is posible to overcome these.
With poppet valves the path is always obstructed. With rotary valves it is possible to have , at least at one instance a fully unobstructed port. I am mostly dissapointed with the automotive industry that the engines we currently use are still not to evolved from the first I.C. engines . Electronics and materials yes. But the basic concept is the same. I do not think a rotary valve engine of any type is the cure for our oil dependecies. But to improve upon the effeciany of a gas engine can not be bad. I hope 100yrs from now guys will still be racing and tinkering with the "old" petrolium style engines. But do hope they are not our primary source of energy for our cars.
I do not intend to make any money with my design. But, for the same reason most of you guys build modle engines I would like to build a rotary valve engine for the fun and to show off.

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Rotary valves

Post by speedsport » Sun Mar 16, 2008 9:52 pm

Rotary valves were used by various motorcycle manufacturers, Kawasaki, Suzuki, Bridgestone, Yamaha, etc. In fact rotary valve two strokes are still being raced in GP today. Ducati has long used a desmodromic valve system, the valves are both opened and closed mechanically, no springs, well actually there are springs but very weak ones to compensate for valve lash. The opening rockers are set at 2 thou and the closing at 0 thou. Ever try to measure 0?
"good enough never is"

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Post by Electric_charge » Wed Apr 09, 2008 7:00 pm

Geez, after reading some of these posts we'd still be back in the stone age if it weren't for investors, R&D, trial and error, companies like Coates etc. etc. Seems to me (I may be wrong) it wasn't to long ago that overhead cam engines were more of a rarity but now it's the pushrod engine. It doesn't seem far fetched that this may be next. I think it's very interesting at the very least. I would like to see your projects on this subject Ben. Another item might be that a company like Coates may not want to give to much info out, I'm sure they want to guard their classified info. Just thought I'd throw my 2 pennies in.

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Post by oldbrock » Wed Mar 11, 2009 9:35 pm

I could see the restriction of the poppet valve when I was an apprentice fitter turner in North Wales in 1950 and set about to design a rotary valve in head. Had the drawings made and showed them to our engineer and he said you've just designed the Aspin engine. He said it left everything else in it's dust until it seized up. We discussed the lubrication problems and I dropped the idea.Peter

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Alternate "Rotary" Valve

Post by CB&Q » Fri Oct 09, 2009 7:37 pm

Myu Dad spoke of a car, way back before I was born, which utilized "Sleeve Valves" which surrounded the combustion cylinder. I believe the car was the Stearns-Knight.

This system was not a "pipe dream", but actually was in production and sold to the public. I once saw a diagram of the system, long ago, but since I am saddled with "dial-up" internet service, only the truly important searches are done.

Just thought I'd throw in 2 cent's worth. CB&Q
One can derive far more personal pleasure and reward from observing Mother Nature's living things instead of Humanity's Madness.....

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Post by david5605 » Sat Oct 10, 2009 7:16 pm

The Mazda RX series of sports cars has had a rotary engine for many years. Their latest is about 230HP and a 9000 redline.

Seems if I just wanted to tinker with one and build a smaller one I'd look into scaling down one of their engines. You can get a older RX7 car complete with running engine for probably 500$ or less.

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