The fact that you got it working that well considering how finicky these small engines are normally, that’s awesome.

The greatest channel of mini motors in the world.

In late 70's and early 80's with friends we tried different things how to improve compression in exactly the same system of rotating valve. We never managed to get more than 70% but mostly it was just around 60% of the theoretical compression. This problem was because surface of the valve and cylinder were not ideal to hold compression. At that time the tools we had were unable to offer absolutely smooth - mirror - surface and lubricating was problem as well. We used petrol mixed with oil which improved compression and reduced heath from friction. We designed 50cc motor but it proved too weak compared to ordinary scooter 50cc motor. However it was fun and we enjoyed it thoroughly. However my congratulation on your design and quite remarkable achievement.

You gotta love an engine that idles at 5,000 rpm! 👍

The sound of the work has become noble.

I think you need to make the valve openings a tiny bit larger in the post-open direction to solve the problem with throttle lag. Here is why: When you have a normal camshaft, when the cam lobe has passed the rocker, and the valve is now closing, there is a bit of "lag" from the point that the cam is no longer holding the valve open, and the valve physically closes. This because the springs need some time to actually close the valves when the cams allow the valves to be closed, since the cams do actually not PULL the valves closed by force. This "lag" is propably considered in the engine design, meaning the cams are a tad bit smaller than the duration you want the valves to be open, to compensate for the closing lag. I mean, theres a lot of mass that the closing spring of the valve needs to get accelerated to get the valve to close, its the valve itself and the rocker arm. And in a engine that makes 10k+ RPM, that acceleration adds up pretty much, meaning, for your rotating valve that actually have zero acceleration - its constantly rotating in the same speed as engine, you need to compensate for that acceleration, with larger valve openings. So I think you need to extend the valve openings slightly in the "forward direction", ergo make the valves to be open slightly longer than now, but still open the valves at the exact same time as now, just wait a tad bit longer before closing them, since what I have understand, you have designed the valve open time directly from the camshaft.

As my college senior project in IC Engines for mechanical engineering, my group designed this very thing except we had two cams, one for exhaust and one for intake. Both went through the center of the cam.

Been following this guy for years- he still manages to amaze me with his skills and insights.

This is the type of content I have missed! I really enjoy watching JohnnyQ90 and 2STROKE STUFFING take a concept in their heads and try making it a working reality.

Back in the 70’s I asked my mechanic/hot rodder dad what I could figure out to improve engines. He advised me to figure out how to do away with the valve train. It took me til the early 90’s and entirely in thought(a few toilet paper tubes for a visual representation), I came up with the exact same answer. Alas, not a machinist, but it is awesome to see it actually work. Bravo! You might think about reshaping the ports in the rotating rod to spiral on the shaft. If the shaft could then translate in and out of the head you could vary the port timing based on rpm.

I agree. The idea and function of this design is amazing!

Greetings from Texas! The rotary valve is not a new concept. I saw some research and a test engine more than 20yrs ago. The main problem they encountered was the heat dissipation problem for the rotary valve. The exhaust side gets very hot and expands where the intake side is cooled by the incoming fuel. This lead to sealing issues and exhaust leaks. Same thing happens if you separate the two and have separate intake and exhaust rotary valves. Great concept though. It liberates the issues concerned with standard tappet valves. Keep the content coming!

Great work! Been interested in rotary valve engines since reading an article about the Ilmor / Mercedes Formula 1 engine that used them (and got banned even before it raced, due to Renault complaining about it). Little tip: Machine your mating surfaces last. I must admit I cringed a bit when you put the rotary valve into the chuck to machine the inner surface... Also it looks like the sleeve inner surface is not as smooth at it could be, but I know it's hard to work at these small sizes. One other thing that makes engines difficult is thermal expansion rates of different materials (and with rotating parts you get different heat distribution through the part than through the static area around it), so keeping tight tolerance between surfaces without them binding / seizing is hard. When there is compression, the ports will be pressed against the sleeve, so I think the critical areas for leakage may be the ends of the valve more than the ports... maybe a simple pair of orings or labyrinth seals to help seal those will improve things with the existing design without having to machine any new parts (just cutting grooves to accommodate them in the existing ones)?

Wow, now that is a fantastic concept. This is a project that needs to be refined, definitely. Outstanding video!

0:40 that was a great shot!

Seriously, it's wonderful and inspiring to watch that being made.... The mind goes through dozens of prototypes and variations... Loved it. I also had in mind a chap who had built a larger, maybe 100cc? engine with the same type of rotary valve arrangement. He didn't have the precision you managed and lost most of his compression. Half the video was him making it, the other half was him trying to start it... These things are notoriously difficult to make gas tight without some clever thought. You did very well by making it so beautifully. So impressed.

I've been watching your channel for a while, and I've always enjoyed it. Im a cnc machinist by trade, and I run 5 axis mills. I love the mix of machining and small engines and even rc on your channel. This episode, though, by far my favorite. A little bit of everything with a cool concept that I've never seen before.

Please keep developing this!!!!! I have been thinking of ways to get this type of motor to work for YEARS!!!!!!! I’m glad someone is finally doing something with it.

Followed you since the starting days and loved every video you've made, would love to try something like this someday, just the effort you put into the ideas and creations is amazing. World needs more creators and people like you. ❤

Wow. Master craftsmanship plus excellent documentation/photography. Amazing.

So Good!! Moons ago, I designed a rotary cylinder head in school 1987-88 ish. My fantastic metalwork teacher said I had no time to hit the exam deadline. He helped me exchange project to design a HiFi stand for my best friend. In a few weeks a nearly finished step style table was made. So nice to see what can be done 😮 Amazing work!

never knew about rotary ports , incredibly interesting that the engine gained some top end , would be cool to see what kind of power & torque curve it gets on a dyno compared with the standard sohc ... i also wonder if having shallower/deeper / different exit angles on the rotary ports would affect compression & power?

The poppet valves probably transfer heat better, and the fuel likely mixes better off the back of the valve (while cooling the valve). The flow is also usually more smooth for the poppet valves. To reclaim these benefits with your rotary valves you could run the intake through the middle of the exhaust tube, and put angled flow diverters in the end of the I&E tubes so the flow isn't hitting a square wall on one side. Even though it's counterintuitive at first, the intake path is probably getting cold instead of simply cooling the rim of the poppet valve, and so your fuel is not mixing well enough for the throttle response to be good. Also, the original design probably puts a little fuel on the glowplug wire while it spreads fuel/air around the head zone and taking that heat. The hot wire goes over the ignition temperature at the end of the compression stroke, causing it to self-time. The new valve directs the flow at the piston, which is not in phase with the intake flow. If you angle the intake port so that it stays nearer the head to greet the piston when it comes back up, and keep the mix nearest where it's going to do nearly all its work, I think this may be easier than running the intake tube through the exhaust tube. Doing both would be very much like the design of an industrial engine, but those are built for steady, reliable performance, not maximum possible performance.

you have amazing talent with machining and building these things Q....Thankyou for another amazing video!

I work as an aerospace valve analyst and we have rotary valves. The 3291186-6 has one in it's e-seal assy. It has a spring loaded seal that presses into the rotary valve, because otherwise it will quickly leak without it, and it's not very good at sealing anyways. Unlike poppet valves in use broadly in aerospace valves and in car engines.

I really love these videos, thanks for the enjoying view on machining nicely working machines!

Ha sido un excelente trabajo. Mis felicitaciones.

Yes, yes, a million times yes, I love how brilliant this channel is

Awesome build! Thanks for sharing.

You pulled it off! I’m not surprised… but I am amazed at what you are able to design, build, and run!! Just awesome

I found this video extremely awesome. as i was trying to come up with a way to make heads for a Buick v8 with the same concept back in 1986. when i was 17years old. i new almost nothing about machining at the time. was just getting into engine. being raised around family that were doing lots of work with blacksmithing, and steam, and hit and mis engines. I had a good understanding of the basics, and what i wanted to improve on. and in preliminary testing of just trying to get it started, was having lots of lag also. and blow by of combustion gasses. I am wonderfully ecstatic that someone has finally made one run. As the timing and valve opening events need to be machined into the leading and trailing edges of the port. it would take many variations to get it perfect i feel. almost like porting a regular head and changing cam to achieve the rpm goal in question. but just seeing the gain in Rpm, because of parasitic gain over the moving parts of the regular valves is very encouraging. defiantly going to subscribe and follow for more of this wonderful experiment. Have a great day. and keep em coming.

This awesome, you surprise me every time. I can believe it work that well.

Worked way better than i thought it would. Smooth throttle response.

Fascinating concept, you can easily up the compression by getting rid of some of the dome. You don't need valve clearance anymore and you can recess the glow plug.

Watching your channel for years and every vid is an example of perfect craftsmanship. But building this cylinder-head is un-be-liev-able !! 😊😊 Greetings from Germany

I actually designed very similar to this back in 2007 in solidworks (trial ;) ). It was big enough to be on a Harley. My valves were spherical in nature and the chamber seal was the "brick wall factor". Also did not have the means or the CNC equipment to even try a small scale version. Props to you! You made it run! This valve tech could be key in finding even more performance/efficiency for the future!

Yay! Thanks for the design teaser!!

STUNNING WORK!!

Wow! Great video! So pleasing to watch!

I switched from mechanical engineering to software engineering during college. I don't regret it, but still nice to see something that I would have enjoyed working on if I had kept my original career path.

Absolutely awesome man. Worth refining.👍

Can you make inline diesel model engine 🙂

I was so excited to see this! I've been recommending a camshaft upgrade or rotory valve setup for so long! Keep up the good work Johnny!

Simply amazing.

Never built it but when I designed rotary valve head I used a Geneva/Maltese gear to revolve the ports. This should allow smaller ports with longer opening periods helping to solve the compression issue. Probably wont work at the miniture level though!

Awesome concept.....cheers!

I had this idea probably about 25 years ago but never had the equipment to do it... pretty cool.. Glad to see somebody making it reality..👍👍👍

That is just about the coolest thing I've seen you make yet!

❤my brother came up with this exact idea 50 years ago!! congrats on seeing it though

Nice works💪

This has been a life long day dream, rotary valve. Now I've seen it done.Thanks for this video.

Absolutely fantastic piece of machining, really nicely done and its the only home made example ive ever seen actually run. I had a chat with an engineer many years ago about why we dont see any rotary valve engines in production. He said it was because of poor performance due to turbulence between the sharp edges of the valve and port, the port is only fully open and smooth for a tiny faction of the firing cycle.

I love the rotary valve concept. I could remember seeing in Carcraft magazine, a prototype dyno caparison of a Ford 302 between what was stock and a rotary port demo and thought this concept was going to be the future for the 4stroke engine. Shame the kinks haven't been worked out for mass production.

Amazing work Thanks

I love this kind of experimental stuff!

This is incredible genius! It's so simple and yet so effective... Maybe adding counter-rotating balance cranks to make it revving more evenly?

Deine Videos und deine präzisen Arbeiten sind immer die Zeit wert!

Dude that's freaking genius

Whoa 🤯 I don't think I've ever seen a rotary valve set up like this! SUPER COOL!

It'd be really interesting to see if offsetting the position of the port opening a bit more to one side to try to get more turbulence in the cylinder would make run better It also might be a good idea to add ramps into the intake sleeve to soften the curve out of the tube or even fillet the edges of the end wall just to try to smoothen the flow into the cylinder I'm sure pulling a 90° turn against a flat wall isnt the best for flow especially at this scale Either way keep up the amazing and interesting vid's it's always intriguing to see what you make and experiment with.

Master craftsman at work again ❤

Your video's are amazing and you are such a inspiration I can't say it enough absolutely awesome craftsman.

That runs really well!

I can't wait to see more done with this, it's gonna be awsome

Dude I had this same idea two years ago. On one hand I’m mad someone else actually did it first but on the other hand I’m overjoyed to see my idea actually work

Puras maravillas , felicidades

I have had this idea in my mind for almost 7 years but no way to actually attempt a rotor valve amazing work

Awesome! I wanted to try such a design since a long time already!

Superb job!

Awesome, thanks for sharing.

Well done, very clever.

*The Intake can be a simple REED VALVE to make it simpler and increase intake flow by 75% since a REED-Valve is fully open during the intake stroke.*

Fantastic system! Big hug from Brazil!!

You know you're a machinist when you're thinking about stepover and cutting speed while shaving.

amazing. Keep it up my dude! I've never seen anything like that, I can't wait to see how you intend on improving it!

I've done some experimenting with a similar idea. The key to optimal performance was using a pair oval gears connecting the crankshaft and the valve shaft, giving longer open and closed times, with shorter periods of partial opening.

Love it!! I guess most won't appreciate the theoretical difficulty here because - machining is cool In '96 I wrote my dissertation on ICE with respect to valve timing and events, ended up studying the rotary valve, a *lot* - fiddly, not least because even the way in which the valve closes and open is different, so dwell is different, how the fuel vaporises in the cylinder is different...etc. It may be worth considering as a 'faster' opening inlet valve or 'slower' closing exhaust might dump compression, for sure at 15k rpm gas flow is important. The original valve durations might not do it. It's been years since I looked at this but consider an early IVC as a rotary has more open area sooner (or later however you look at it) and perhaps lower inlet gas speed overall - similarly for EVO. that 'massive' unobstructed hole will empty pressure quite quickly For the record, I was hypothesizing a variable valve train where the throttle was a secondary sleeve around the inlet valve. To achieve this of course there were separate inlet and exhaust rotary valves... Also supposedly some squish from the upcoming piston to help with swirl breakdown. Gas flow is not easy, nor combustion chamber shape. I also seem to recall the presence of Ceramic SiC or Carbon-carbon components in the valves because of sealing and cost was not allowed to intrude. Massive Kudos for getting this to work, quite a bit of behind the scenes thought went into that. Take heart that many of your 'issues' should be taken in comparison to the poppet valve that's been around for more than 100yrs. or to put it another way compression is all relative.

A true designer and engine pro!!

Great work, love the pocket nc, another dream shed machine. I love these little motors. When I get more play money, I plan on getting one of them to play with and maybe build into whatever might come to mind.

Fascinating machine work & fabrication. I stopped to watch when I saw rotary valve. I always read anything to do with the Coates Spherical Rotary Valve cyl. heads & engines, because the performance was so superior to poppet valve engines. Good luck on further development & thanks for sharing!

Great job!! Very impressed!!👍👌

With all the milling equipment and your skills I would love to see you make an opposed piston engine. No valves, just intake and exhaust ports cut into the cylinder walls with diagonally cut ports on the exhaust with runners for improved savaging and the swirl action to aid cylinder filling.

i LOVE the sound of this engine with non valves.

This is awesome. I've been working on this concept for automotive V8 engines for a while.

You don't have an idea of how much I was missing this content

Wow !! The most fascinating thing i have seen for a while now.. there are some challenges to solve such as lubrication and compression but this is actually a very interesting idea.. I don't know if there is something similar in the industry but i can see a lot of advantages for this system.. less moving parts... No camshafts springs etc.. smaller engine size.. Wow just Wow !! Well done mate ❤

Worked a treat as usual. Lots ov luverly rpm 👍

Nice work man 100⁰ 👍

congratulations!!

Very nice work. I had the idea to make something like that around 2008. I have only just gotten into using CAD CAM and 3D printing, but I have an automotive background. I thought it would be cool to reduce reciprocating weight within the valvetrain. With that design, there is none within the intake and exhaust part of the cylinder head. After watching many UKposts videos that just show up because of the algorithm and my interests, I learned that this type of design has been around for a long time. I would like to make a suggestion. You should make a small motor dyno to test those engines you acquire and modify. Or you can just get one that is made for RC engines. I just read the caption, one problem mentioned is compression loss through the rotary valve system.

I think this project is awesome!

Nice work, maybe consider a duel rotary head, then you would be able to individualy time the rotors and get a bit more flow, maybe some more compression would help too. Keep it up Johnny love the channel.

Sounds much better - but you can enlarge holes to make more air coming in/exiting basically making "hot" cams with more overlap. You can also try shaping the ports in like "tear drop" to achieve different progressive ways of valving (it may also create small vortex inside the exhaust/intake while opened). Really cool idea but I would love to see little dyno on those engines with each mod and comparison on other engines you own! (maybe a table so we can also compare power/cc?). Thanks for video!

This is just crazy I can’t well am speechless 😮 I wish you al the success you deserve it

Awesome work! I have made a rotary valve 3 cylinder way back in 2013 or something. Ran like crap and had loads of other issues, but it was made from bar stock and it still is a nice thing to look at on the shelf.

Watching a 6 axis CNC do its work is always mesmerising

They're looking into this for car engines... you just proved it is possible at least on a small scale... but this could theoretically reduce pumping losses vs poppet valves. Would be cool to see this in a car one day.

It’s got the sounds and some of the characteristics of being lean except it idles down and doesn’t hang, I think the exhaust is either not opening soon enough or long enough. I find a similar response in my motors if I port them heavy and try to make power but use the stock congestion exhaust pipe. So I would look into fixing the exhaust port on your rotor valve timing. It might be off a bit. Great video and post thank you

Ive been waiting for you to jump into the rotary valve band wagon.. thanks!! Great job!!

Really nice concept. I have a 12cc valve-less 4 stroke with a rotary cylinderliner…works great!