Rotary valved engines

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Re: Alternate "Rotary" Valve

Post by dly31 » Sun Oct 11, 2009 8:57 pm

CB&Q wrote: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
Stearns and Willys both used the Knight sleeve valve engine for a time. It's advantage was mainly quiet operation but sealing and lubrication problems did not permit it's continued success against the poppet valve. There have been a lot of sliding and rotary valve designs but as of now none have proved overall superior to the poppet valve. I personally do not believe that the valve springs account for a significant amount of the overall power loss as heating of the springs does not seem to be a problem and that is where the losses would have to go. Inertia and spring action do not in theirself represent any power loss. It should be fairly easy to measure the power taken to drive a valve train and compare various arrangements. I agree that other valve arrangements offer less restriction than the poppet valve, but the airflow in a gasoline engine is restricted by the throttle almost all the time in a passenger car engine and reduced restriction does not equal improved economy. I certainly like to see new ideas and hope this one works out.

Don Young

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Post by ADGO_Racing » Fri Apr 02, 2010 1:56 am

The valve springs do get hot.....In the engines we work with, we have sprayers in the valve cover to keep the valve springs cool.

Also we have a spin tron, which is specifically designed to measure valve events and losses. The valve train is a massive loss of energy. So are other things the engine operates, such as the alternator and water pump. You would be very surprised to see the losses there!

As for race teams using a rotary valve design. Most series rules specify poppet valves. Drag racing may be an exception, but most circle track rules do not allow for a Wankel engine or any type of valves other than poppet.
F1 does allow pneumatically or electronically controlled valves.

I too have thought about this theory of rotary valves over the past 20 years. I have had a few different designs in mind, but it always comes back to lubrication. One day when time permits I may build a prototype or two, to see exactly where the design flaws may exist. They may not be insurmountable.

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Rotary IC Engine

Post by CB&Q » Fri Apr 02, 2010 8:02 pm

david5605 wrote: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.
The rotary engine based on the original design by German Wankel uses a 3-cusped rotor contained within a chamber called a "trochoid". The design uses NO valves. The first automobile using one of these was the NSU-Wankel Spyder, built in Germany, about 1965. The company I worked for (Victor Mfg. & Gasket Co.) bought one of these cars, and our Field Test Engineer tore the engine apart, in order to determine the possibility of providing sealing products for them.

I have a picture of the Wankel engine being disassembled; if desired to see it, ask, and I shall attempt to post it. 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 magic9r » Fri Jul 16, 2010 2:53 am

Electric_charge wrote: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.
Coates, like (Moller Sky Car) are a very nice investment/development company allowing their directors to have really nice houses and very expensive toys.
If there really was anything in it they'd have had valve systems on engines on the various TV vehicle build shows, and don't think for a minute that F1 teams would miss a trick if it was any good but Coates seem to have a vested interest in stopping their product reaching any mass market before they have a fat licensing deal,
Hmm, sounds fishy to me,
But I'm a nasty old cynic :D

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Re: Rotary valved engines

Post by boilermaker » Sun Sep 19, 2010 8:42 pm

I would like to point out that most of the rotary valved engines that were mentioned were 2cycle and the piston covered and uncovered the ports ,the rotary valve only let the mixture into the crankcase and then prevented it from coming back out.
Nothing like a true rotary valve, which would need to be on the intake and exoust on a 4 cycle engine, which is more clean burning and needs no expansion chamber.
I wonder if the gentleman ever did build a true rotary valve engine and if so i would like to hear about it..
boilermaker sam

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Re: Rotary valved engines

Post by scooterwrench » Sat Dec 11, 2010 4:36 pm

I don't know if y'all know this but the Wankel rotary engine was derived from the rotary valve the Germans tried to perfect in Messersmidts(spelling don't count). The problem they had was sealing. I like that pic of the honda head, using one valve for intake and exhaust is slick as (well you know what). And to all you naysayers this is a VERY viable alternative to reciprocating valves.

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Re: Rotary valves

Post by flutedchamber » Thu Sep 22, 2011 12:36 am

speedsport wrote: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?
Honda used basically the same valve system..minus the weak their 450 and 500 twin models. Torsion bars were used in place of valve springs.

I think with work the rotary valve will work. The only drawback to rpm will still be the feet per minute that the piston travels along with the rpm limit on connecting rod bearings.

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Re: Rotary valved engines

Post by steamin10 » Thu Nov 03, 2011 4:32 am

An old post, but here goes. In the Honda head, I dont know why they tried torsion bars. One of our racer guys modified tha 450 head for springs, and got better rev performance by a thousand without any tweaking.

The Wankel had a fatal flaw, in that at high rpm, the flame front could not keep up with the rotatation of the moving trocoid shape, leaving alot of unburned fuel. That cut power and fuel economy in high speed travel. Bad news for smog watchers.

The poppet valve train is just a flat waster of energy. In our circle track motors, we use the largest headed valves we could stuff in the heads, with the lightest gram weight, to drop the bounce, and flutter from high rpms. Lighter rockers, roller cam followers and all went to reduce the valve train weight, and rolling friction over sliding, to make gains in power without doing anything else. We drilled piston skirts, to reduce weight, and massaged rods by hand to reduce reciprocating weight and eliminate cracking by smoothing and hand polishing..This is why they use short stroke engines in the first place, to get the rpms up and get more power beats per minute. Old school, but used to be fun.
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Re: Rotary valved engines

Post by wildun » Sat Sep 14, 2013 6:48 am

boilermaker wrote:I would like to point out that most of the rotary valved engines that were mentioned were 2cycle and the piston covered and uncovered the ports ,the rotary valve only let the mixture into the crankcase and then prevented it from coming back out.
This discussion as I see it,was really about the possibility of using ceramic (coated?) exhaust and inlet valves to replace poppet valves, in a four stroke, - and of course, the same configuration could also be used in two stroke as well, dispensing with the cylinder ports altogether, the inlets could be fed by blower and the petroil lubricated bottom end could then be dispensed with and lubed by a pump.

I agree with BOILERMAKER that in karting circles, the word "rotary" was ( incorrectly) used in the two stroke engines with rotary disc inlet valves, but these still used cylinder ports for exhaust and transfer. They were very successful in racing motorcycles and karts and in many road bikes as well and the first real successful valves of this type were produced in racing MZ motorcycles in the late fifties - but they were crankcase rotary inlet valve only!

The rotary exhaust and inlet valves ( in the cylinder head) have been tried by many experimenters and still need to be proved, no one has been brave enough to put them into production, let alone make them successfull, I think the cross and Aspin engines came close but never were 100%, probably due mainly to the metallurgy and lubrication of the day.
There were reports that this type of engine could use much higher compression ratios without introducing detonation.

I see no reason why the guy who started the thread shouldn't persevere with his efforts to make a model engine of this type successfully, however I'm not so sure about the manufacture of spherical valves, - could be a bit involved, but whatever he thinks, he should give it a go, - a bit expensive maybe, but a lot of fun developing it and nothing to lose really (except a few dollars of course!).

Being new here, of course I forgot to check when the last post was made, - however, I think I'll just let it be and maybe I'll get a reply anyway, maybe even from the guy who started the thread! :oops:

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Re: Rotary valved engines

Post by JackF » Sat Sep 14, 2013 10:40 am

I'm glad this thread was opened up again; makes for interesting reading.


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Re: Rotary valved engines

Post by ken572 » Sat Sep 14, 2013 12:52 pm

I agree with Jack.

This is a very interesting topic.

Thanks for this, Ben. :wink: 8)

Here are some links pertaining to the subject:

Rotary-Valve Internal Combustion Engines. - (ALL) - (GREAT READ) ... alveIC.htm

Coates Engine (VERY COOL)

The Quasiturbine or Qurbine engine

Ken. :)
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Re: Rotary valved engines

Post by scmods » Sun Sep 15, 2013 8:48 pm

I saw this thread a couple of years ago. I used to be an avid reader of Popular Science as a youth and am well familiar with "new" and "revolutionary" ideas that were stillborn for failure to solve some basic engineering problem like lubrication issues or a consequential maintenance problem like coking of the lubricant or wire drawing. Or, they were just eclipsed by systems that worked not just "well enough" but pretty darned good.

The basic rotary valves (like the Knight of the 1920s) appeared to be a variation of the Corliss steam valve, only with a full-circle rotation, rather than the reciprocating "hook and drop" steam valve, which had speed of operation issues. The operating principle is a relatively narrow, but long port is opened at right angles to the short axis, creating a fairly large opening almost immediately, whereas a cam opens slower for the same amount of rotary, and crankshaft, motion and must accelerate and decelerate the valve as well. The rotary valve action is continuous as well. The improved volumetric efficiency is a goal worth pursuing, but the problems crop up right away in the internal combustion engine. As internal combustion engines operate at much higher speeds than steam piston engines, lubrication issues become significant just from a frictional standpoint not to mention the problems caused by trying to provide lubrication at the temperature of exhaust gasses. Then materials get exotic, just to get past the basic issues, and what is the benefit?

The bottom line is the internal combustion is a trade off, especially in the valve area. Cooling and lubrication of a small stem of a tulip poppet valve running in a guide that has good surface contact with a water-cooled casting is a well established system that works well, in spite of it's limitations, like accel/decel and inertia. I question the wisdom of trying to solve a "problem' that from all appearances, doesn't exist, given the millions and millions of conventionally valved engines operating reliably under widely varying conditions, operated by as a diverse a collection of drivers as could be imagined.

I would venture to say that improvements in the internal combustion should be:
1) In the direction of increased operating temperature which addresses the efficiency equation in the area of hot side/cold side difference. The greater the difference between the two, the higher the theoretical efficiency.
2) Realistically developing a stratified charging system that allows igniting a mixture lean enough to burn to completeness. The carbon monoxide in exhaust is energy lost as it is flammable and is just thrown away. I understand that is one of the goals of the direct injection research.

It is in this area that genuine improvements can be made, not in the "improvement" of a technology eclipsed successfully 90 years ago.

I'm working on improving the Austrian Self-Sharpening Razor.

This should attract some opinions.

Bill Walck

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