Making a CYLINDER Head with NO Valves but ROTARY Ports!
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- Опубликовано: 23 фев 2024
- This is my first attempt at making a cylinder head with a rotary valve, instead of the traditional poppet style valves.
Being my first attempt, I'm pretty pleased with the results.
Original cylinder head with poppet valves reached 13,500 top rpm while whith the rotary valves 15,800rpm.
That itself can't tell much, because I can definitely tell that compression is lower than before, and that's where I need to focus on my next attempt.
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The fact that you got it working that well considering how finicky these small engines are normally, that’s awesome.
Hey! Nice seeing you here lol 😆
@@bricknplay
This channel is great, of course I’m here! Love these engines.
@@Calthecool lol saaameeee
Yup, mine runs like shit
2jz pls😢
The greatest channel of mini motors in the world.
I'll 2nd that
By far the best 👌
Agreed
I agree. This guy has all the skills to make all of these and I can't figure out how to operate my lipo charger.
Agreed
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.
I wonder if "compression" rings similar to a piston could be cut into the rotating valve shaft, this way the compression would push against the rings instead of flowing past the shaft would help...the rings on a piston spin as well..just not at a super high speed like would be on a rotational assembly. Maybe those "L" shaped rings that use the pressure to seat the rings on compression, but let them relax when there is no compression could help. Plus then the rotating assembly could be cut smaller than the bore diameter to reduce friction/heat and assist in lubrication...adds complexity, but also reduces/eliminates a few other problems...especially with expansion of the shaft due to heat vs the bore of the valve assembly
My granparent worked on experimental engines with that system at Bultaco and the main issue they had was sealing/lubricating the port tube. He told me it burned oil like a two srtoke, so it did not make much sense comercially.
@@blar2112I've ridden a few Bultaco's on farms. They still are beloved bikes.
@@haydenc2742You could machine a flange into the head between the intake and exhaust ports and split the sleeve and the valve to make a "labyrinth seal" between the ports. It's going to get complicated because of the size constraints. Maybe the intake should be on the timing belt side so that the exhaust end can be sealed with a plate. The carb would then have to go on top of the head then but that would make the flow path straighter.
@@dosgosnow Bultaco makes electric bikes.
You gotta love an engine that idles at 5,000 rpm! 👍
The Concept of a Little Motor With an OBSCENELY Idle and Redline RPM is Delightful.
I wonder what the Dyno Graph of this vs the original would be
@@ericlotze7724it's basically a racing engine but insanely tiny.
Its cause it makes little power below 5,000rpm and coupled with its pretty much light flywheel, it needs to rev fast at idle.
If you were to double the weight of the flywheel on a normal car engines you could get it to idle below 700rpm.
@@IIGrayfoxII if you have a carburetor you can just turn down the idle screw. I have a power wagon with a 360 that will idle at 300rpm if I turn it down. It sounds like a Harley and doesn’t spin the alternator fast enough to charge but it’ll idle at 300rpms.
@@minnesotatomcatWhats the response time on that engine when you try to leave idle?
At 300rpm with a normal flywheel it will be on the verge of stalling.
The sound of the work has become noble.
And sampled.
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.
so you mean shamfer/scallop one side of the valve exit effectively making it like more of an oval?. i think there is another problem for tuning and throttle response and that is air velocity. at lower rpm it will give too much air too quickly resulting in poor mixing.
@@BCzepa Kind of. I mean, when the cam lobe no longer touches the rocker, the valve isn't pulled closed by the cam (cam can only push, not pull), but by the spring. Since the rocker has a inertia, and also the valve, it means, theres a "lag" from the point the cam no longer holding the valve open, and the valve actually physically closes.
The engine designer, of course took this in consideration, and made the cam lobe smaller to compensate for this.
The rotary valve closes as soon as it wants.
This means, JohnnyQ90, which measured the lobe and constructed the rotary valve after this, means that the valves are open too short time. He needs to take the rocker and valve inertia lag in consideration, and make the openings slightly larger.
@@sebastiannielsen ive invented an engine which could utilise a rotary valve (in 2-cylinder configuration) but not exposed to combustion. where do i start to get it built? its complete theoretically, i only have a few fluid dynamic questions to answer (ive never created a model, only crude drawings) it is a uniflow 2-stroke which does not rely on an external air pump. i have solved many engineering problems by thinking about it constantly over the past 3 years.
YES the port/slot needs to be longer to provide enough duration and it needs more overlap
Been following this guy for years- he still manages to amaze me with his skills and insights.
Agreed!
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.
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.
Yep both make great small engine content
2stroke stuffing lost my views with that bullshit wide screen lense stuff he started doing
check out ledan
I started following 2StrokeStuffing and throwing money at his patreon when he was just finishing up the timing chains for the twin rotary exhaust and intake tubes on the brute force engine..... when he picked the head back up the other day......
I agree. The idea and function of this design is amazing!
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.
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!
Some wonderful random knowledge that I will keep with me forever. It's crazy to think if they found a way to solve the exhaust port expansion how ice cars would be today.
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.
Perhaps use some old tech...
the "atmospheric pressure" blower that a 2 stroke Detroit Diesel has to use to even be able to run.....used on this engine will boost compression..
or the turbocharger that feeds into the Detroit "blower" for more power......
both will increase cylinder pressures on this engine as well as increasing "blowby" losses?
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. ❤
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!
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.
Wow. Master craftsmanship plus excellent documentation/photography. Amazing.
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.
The concept of a rotary valve?
It's fairly new to me as well, I actually found out they existed via another channel called "2strokestuffing" where he's trying to make the most powerful (by displacement/power output) 50cc 2 stroke engine, amongst other projects.
I had no clue about it prior to that and I pride myself on being a nerd of weird and interesting engines, big and small. If you find that kind of thing interesting, check him out! He's Norwegian but speaks English in his videos. He's a cool dude. Very different from this channel in approach/video type but very enjoyable. Give him a look!
you have amazing talent with machining and building these things Q....Thankyou for another amazing video!
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.
Yes, yes, a million times yes, I love how brilliant this channel is
I really love these videos, thanks for the enjoying view on machining nicely working machines!
This awesome, you surprise me every time. I can believe it work that well.
That is just about the coolest thing I've seen you make yet!
Absolutely awesome man. Worth refining.👍
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 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!
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
Yay! Thanks for the design teaser!!
Worked way better than i thought it would. Smooth throttle response.
Ha sido un excelente trabajo. Mis felicitaciones.
STUNNING WORK!!
Wow! Great video! So pleasing to watch!
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!
Deine Videos und deine präzisen Arbeiten sind immer die Zeit wert!
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?
Read other comments from people that have dynoed engines converted to rotary ports....
even though they did not have access to the accurate tools show here.
In one case the power output was less than the original through losses past the (too great a clearance?) of the rotary ports....
The engine can rev faster because now there's less reciprocating mass, once you eliminate the traditional valvetrain.
However, I see two issues there:
1 - Lubrication - either the rotary valve gets oil from the engine oil system, and this means that the engine will burn oil and spit it out of the exhaust (nasty and polluting + fast engine oil comsumption), or the rotary valve will need to rely on sealed bearings (expensive and unreliable when compared to plain bearings + oil, and will have problems with port and combustion sealing)
2 - Heat of exhaust port - as mentioned by @mikedavis6566, the exhaust side will suffer heat expansion compared to the rest of the piece, and this may seize the rotary valve, though, this might be mitigated by using a second dedicated, somewhat "looser" rotary valve for the exhaust port, along with oil cooling.
Awesome concept.....cheers!
Simply amazing.
Nice works💪
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 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..👍👍👍
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 guess high leakage and/or high oil consumption might be other issues.
Would supercharging and turbocharging overcome this turbulence effect...
just cram it in.....
it all helps with turbulence in the cylinder for good mixture spread??
I dont think so, turbulence is caused by the velocity of the gas, more velocity, more turbulence. Thats how I see it. The Tesla valve works in a similar way, the greater the force of liquid, the greater the stopping power of the valve. @@JohnSmith-yv6eq
Master craftsman at work again ❤
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 ❤
That runs really well!
I love this kind of experimental stuff!
Your video's are amazing and you are such a inspiration I can't say it enough absolutely awesome craftsman.
I can't wait to see more done with this, it's gonna be awsome
You don't have an idea of how much I was missing this content
Awesome! I wanted to try such a design since a long time already!
This has been a life long day dream, rotary valve. Now I've seen it done.Thanks for this video.
Amazing work Thanks
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.
Whoa 🤯 I don't think I've ever seen a rotary valve set up like this! SUPER COOL!
Superb job!
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.
Well done, very clever.
Fantastic system! Big hug from Brazil!!
You know you're a machinist when you're thinking about stepover and cutting speed while shaving.
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.
This is incredible genius! It's so simple and yet so effective... Maybe adding counter-rotating balance cranks to make it revving more evenly?
Great job!! Very impressed!!👍👌
I have had this idea in my mind for almost 7 years but no way to actually attempt a rotor valve amazing work
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.
This is awesome. I've been working on this concept for automotive V8 engines for a while.
Nice work man 100⁰ 👍
Awesome, thanks for sharing.
Puras maravillas , felicidades
Worked a treat as usual. Lots ov luverly rpm
👍
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!
i LOVE the sound of this engine with non valves.
This is just crazy I can’t well am speechless 😮 I wish you al the success you deserve it
Can you make inline diesel model engine 🙂
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!
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.
Great vid, It would certainly fix the issues of an engine damage when a timing belt snaps
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
congratulations!!
That is really cool
Ive been waiting for you to jump into the rotary valve band wagon.. thanks!! Great job!!
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.
I think this project is awesome!
❤my brother came up with this exact idea 50 years ago!! congrats on seeing it though
Watching a 6 axis CNC do its work is always mesmerising
maybe you have to try with 2 rotary valves to seperate the exhaustgases from the fresh air fuel mix? great work, love your channel! keep going!
best regards
Brilliant! I never thought about combining different materials 4:45 before using CNC. That’s a good lesson for me:)
i love this idea! I think the problem now is that it sucks in additional air from beyond the carburettor, hence why it keeps so high in the revs after you release the throttle. Getting that sealed will be a big challenge, but not something you wont be up to
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
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.
But you built it, and it actually ran? Sounds better than I could do. Also sounds like a cool story and an awesome piece of shelf art/conversation piece.
You ever get it down and run it just for fun even though it's not "sorted" so to speak? I probably would lol
@@goosenotmaverick1156 Too much of a hassle to clean the engine and oil it after running to get all the methanol out. I bet it's little rusted inside from sitting. Need to find the the flywheel, have not seen that in years. Just might give it a go next summer. If I remember.
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 RUclips 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.
Dude that's freaking genius
Bravo.You are amazing
Very nice job.
I've never seen anything like that, awesome!
A true designer and engine pro!!
Mad Skills