Rotary Valves Make Normal Valves Look Silly - Why Aren't We Using Them?

[@d4a]

Support the channel by shopping through this link: amzn.to/3RIqU0u Patreon: www.patreon.com/d4a Become a Tuning Pro: hpcdmy.co/dr4a Become a member: kzbin.info/door/wosUnVH6AINmxtqkNJ3Fbgjoin Motivation: kzbin.info/door/t3YSIPcvJsYbwGCDLNiIKA

[@classicrestouk]

Your videos remind me of a book which was vital in my years studying Motorsport engineering. Do you also have this book by professor Blair.?

[@scivirus3563]

think its a bit to late unless hydrogen fuel becomes more mainstream and easier to store ..Electric engine still has it beaten

[@importanttingwei7747]

2 strokes are the highest revving engines

[@pgtmr2713]

Rotary valves need to borrow apex seal technology from rotary engines. Make the rotary valves easy to get to for replacement of seals and durability can be less of a concern.

[@ROBOTRIX_eu]

..maybe rotating verticaly..

[@nestormoctezuma4695]

This man just makes me want weird engines in my cars.

[@Revengilate]

Real

[@pastaalalamborghini]

Idk about my car but I certainly want a garage full of gokarts with all sorts weird engine designs

[@workdesu]

no shit. bro single handedly convinced me to bike carb swap my daily driver. imagine running carbs in 2024. but it was worth it. so much fun

[@lamia197]

Before watching: The engine in my car is fine. After watching: I want a bevel-drive, desmo, vr-5, contra-rotating twin crank design, two stroke diesel engine in my car.

[@markm0000]

@@workdesu when there’s a massive EMP you’ll be the only guy driving home.

[@downix]

I designed a rotary valve system once for a project, and the sealing was always a headache. I could never get it to last more than a few hours. Bravo to these engineers for solving these issues.

[@zedostenso3069]

Use of a carbon type seal like used in turbo fan jet engines may have worked would be interesting to see. Cheers

[@JinKee]

Did you try apex seals on a triangular valve rotor?

[@downix]

@@JinKee no, I hadn't... *Runs to check his design*

[@JOutterbridge]

Aside from using carbon/apex seals the best way to keep the sealing protected is by cooling. Just like a turbocharger, air or liquid cooling to keep temps stable for long periods of time. Air usually isn't feasible except for small applications but it's worth a shot.....

[@kebeleteeek4227]

Why didn't you make the rotary valve in tapered form (pushed by a spring on one side) .. ?? .. so you don't need o ring seals ..

[@sevnpicoferro5352]

You can have 20 advantages for a thing, but one disadvantage can be too harsh and kills it. Thanks for the video

[@mrcryptozoic817]

In this case, that one disadvantage is trying to get Ford, GM, et al to use any technology they didn't invent. They will likely buy it, get the rights and then bury it.

[@RekySai]

Have you ever heard of physics? That's what makes this so much worse. It's just not better in any way

[@cesarescrignoli442]

⁠@@RekySaithere’s no physics in the way here, only bad timing and early stages development

[@ibrahimsued4906]

@@cesarescrignoli442 I suspect you're wrong for there are torque advantages in 2 valves per cylinder against 4. So, 'breathing' less has it's advantages

[@Ave_Satana666]

You're just Pavlov into shitty cars

[@protestantanon2534]

35 year old man here, I learned more about how engines work in the first couple minutes in this video than I have ever understood. You’re an exceptional teacher, really appreciate it.

[@vivangreco1710]

As a young man, many years ago, I remember ruminating over the limitations of conventional poppet valve designs. The idea of interrupted cylindrical rotary valves exactly like this occurred to me. I remember showing my sketches to an engineer friend of mine. He got very excited and enthusiastic about my idea. This was years before a quick Google search was even a thing. When we began to search patents and technical designs, I realized that my "brilliant ideas" was decades old, and literally thousands of people had come up with variations on this idea, and the issues with sealing, expansion under heat and pressure, and all the technical problems you list in this video were well understood and my idea wasn't unique or novel at all. For about three days I thought I might have stumbled upon that million dollar idea all tinkerers and want to be engineers dream of, only to realize I was at least fifty years late to the party.😂. This was an excellent video, and watching the excellent animations of the rotary valve idea was like seeing my rough sketches come to life. I hope someone is able to truly make such a drivetrain into a reliable real-world design. Seeing that BSA V-twin engine actually running and racing is delightful.

[@actionjksn]

I'm 59 and when I was 15 I came up with the idea of a CVT transmission. I don't know if it had already been invented at that point. My wife actually has that kind of transmission in her Nissan Murano.

[@haydenf1353]

This exact same thing has happened to me many times before. I’ll have a brain blast for something revolutionary only to learn it’s existed for years or decades. The pinnacle of this habit was an idea I had for an aircraft engine that used the compressive force of fast moving air instead of impeller blades. As it happens, this is called a ram jet engine and has been around for ages. Needless to say this kind of thing doesn’t happen much anymore now that I’m older. Edit: forgot to add that I too had an idea for a type of rotary valve in my 20’s. But it wasn’t drum shaped like the one in the video, it was a rotating disc more or less. Again, turned out it has been tried before and didn’t seal 🤷‍♂️.

[@LawrenceOrsini]

Have a look at Coates international, he actually got it done and they ran like a champ. These offshore unlimited racing for quite a few years.

[@mennovanlavieren3885]

This comment should have more likes. Many inventions in the past have been invented simultaneously by multiple smart people who sat down and thought about the problem. However we only remember one of them, because of our innate human urge to glorify hero's and defend them religiously against anyone who dares to question our believes. This not only hurts the others who deserve equal credit. But it also discourages people to pursue ideas, because common folks cannot have good ideas in this world view. "Who do you thing you are to have a good idea?" type of thinking. Also if their solution works and they have cracked the problem, then most likely they get bought out and the patent disappears somewhere in a drawer. In practice the use of most patents is to keep others from breaking the status quo with a new invention in "your" market. Patents usually mean a 20 year delay for the mass adoption of an invention.

[@joshuathomas6275]

I think you should give yourself a bit more credit than that. You are just as brilliant as the person who first thought of this. The mind of an engineer is incredible

[@carmium]

I don't really speak engine mechanics, but your explanation was so clear that I was usually a half step ahead of what you were going to say next! A really good presentation.

[@no-ic5gw]

This. Very fun listen

[@ursula662]

I’m an engineer who trains apprentices, and watching guys like this help immensely with finding ways to communicate technical problems and solutions to laymen or inexperienced pupils.

[@slyy4096]

Actually the 1st minute is not so correct. When the valves close, they actually push camshaft to give energy back.

[@alexmanojlovic768]

​@@slyy4096most of that "pushback energy" is probably lost in friction & "taking up the slack" in timing belts/chains & hydraulic valve lifters etc. It's probably so negligible that he didn't bother mentioning it!

[@slyy4096]

@@alexmanojlovic768 also you don't need to press the spring of a floating valve as much lol

[@JohnSmith-em9ks]

As an automotive engineer for 37 years, I love the way you deliver your knowledge on an easy to understand level for all.

[@krebgurfson5732]

i don't, anyone clicking on a topic like this has a pretty good understanding already or they wouldn't care...

[@Mlyodas]

​@krebgurfson5732 this came up on my recommendation, I am in no way involved in this field ( I'm in the medical field) but his explanation was clear and easy to understand. I think making the effort to make things understandable serves to introduce these topics to a wider audience and get them interested even if it makes the experts feel like it was too simple or lacking detail.

[@enjay8950]

ive been an automotive engineer for 38 years wow look at us go

[@antimotors5429]

​@@krebgurfson5732I have nearly no understanding on this sort of topic, and yet this man made it incredibly easy to understand, so you're talking out of your arse

[@kennethcohagen3539]

A guy in Canada invented what he calls the Coats spherical valve engine. The valve is round, like a ball instead of a rod. Both have holes in them, but the hole in the coats valve has a a restricted shape that allows the air to flow with higher velocity when it’s starts to open and is unobstructed when it is fully open. When these heads were mounted to a ford 302 it ran at 13,000 rpm or so.

[@francisjohantgen1382]

Is that the guy that was in Car Craft Magazine back in the 80's?

[@BastardX13]

I recall a system for Harley Davidson as well. A custom bike was built and shown perhaps? 20 years ago or more. An interesting concept.

[@mikeswierczek]

I came here to comment this. I remember reading about the Coates Spherical Rotary Valve engine almost twenty years ago. If you search the web, one of the patents for it was filed in 2004. It makes me wonder if they genuinely did solve the sealing problems.

[@Enemyofdabeazt]

Like a ball valve in piping?

[@GNUBRAIN]

I designed a dual overhead rotary valve system in 1963 using single long shafts. In 1966 I was living in France and met a guy who had designed a similar system and manufactured a custon head for a Renault Alpine engine, He raced the car that year at Le Mans. Unfortunately I was unable to accept his invitation to accompany him and his team to the 24 Hour race that year and due to returning to the states I never found out how it performed, although I believe their car finished the race. Very interesting video, thank you.

[@Shifty_Malone]

So a rotary valve Alpine raced at Le Mans in 1966?

[@Timbo_tango]

Ford Australia had a 6 cylinder in their RND department back in the late 60's but it was decided back then at that time not reliable enough to put into production. My Dad who worked for Ford Geelong told me one of the employees bought the motor after they were done testing and put it in a clinker speed boat which sank after the pilot tried to make a turn on the lake at +11,000 RPM. They had left the heavy flywheel on the motor which refused to turn with the boat and broke through the bottom for the hull with the immense centrifugal force.

[@CockatooDude]

@@Shifty_Malone This might be a good subject for a mini documentary. It'd be cool to learn about.

[@rientsdijkstra4266]

@@Timbo_tango Sound like a scene from Laurel and Hardy, or Charlie Chaplin? The engine refused to turn with the boat😅

[@joeclark7888]

​@@Timbo_tangoI'd say it's worth looking for and salvaging! 🌞

[@aussietaipan8700]

Back before the last ice age when I was an apprentice mechanic, at Fords training center there was a 6 cylinder engine with twin rotary valves. This was a live and working motor that was in the dyno room. The normal pop valve 6 would rev to max 6500 RPM, the same engine with the rotary valves would rev to 11000 RPM, the weakness was the bottom end. The pop valve 6 would make 147KW power and 287NM torque at 6000RPM and 3000RPM respectively. The rotatory valve engine 235 KW and 315NM at 8000RPM and 3400RPM respectively. Great video on this topic.

[@gregrice1354]

Wow! Thanks for wisdom and positive feedback from ice age! :-)

[@monoracer_]

What volume did this engine have?

[@AdamEarl2]

The only issue that Ford had was the lack of flux capacitors. We’re experimenting with some right now and its been very promising.

[@superman9772]

@@AdamEarl2 i hear doc brown is working on it

[@jamesmedina2062]

So the bottom end needed to be robust but otherwise it worked great? Sounds like something too good to be true. Since my own Ice Age vehicle a 71 Ford with 351 Cleveland it's wild to see how much progress there has been on engines, including computers, injection, friction-reduction, metallurgy, modeling, boost, etc.. from back then and same goes for the ultra strength steels used to weld up cheaper unibody frames and bond together fancier frames. I think the biggest barrier today just as in Congress is battling with dinosaur technology hogging the roadways. Super light cars can be made but they won't survive impacts with heavy vehicles. Ideally I think we need heavy vehicle lanes and light vehicle lanes, or just separate streets/roads.

[@vulekv93]

This channel is great weapon against cynicism and lethargy. I don't want to wax poetic but your videos really lift my spirits up and give me food for thought! Cheers mate, great video as always!

[@xenuno]

I think you're just saying that but I don't feel like doing anything about it

[@illbeyourmonster3591]

Whats interesting is how hard YT now works to keep that ignorance and lethargy in play on certain subjects by censoring anyone who dares expose said ignorance and lethargy for what it is.

[@illbeyourmonster3591]

@Benzley722 Except too many of the things we use every day have nothing in regards to longevity and efficiency built into the designs.

[@LittleXtra]

​@@illbeyourmonster3591 Yes, countless scientists with vast wealths of knowledge are hiding this specific info from only you... ...or you just don't understand the subject at hand as well as you think you do? KZbin uses a standard algorithm to give you what it thinks you want to see so it can make money on the ads you watch. This video is horseshit for so many reasons, but only one keeps it from production, it's not what OP says. Even if you think it's true because it sounds nice and you want to believe really really hard, doesn't make it so. Not trying to be a dick but you're falling into the same trap you're claiming exists but it's your own.

[@davidnkamau]

If I had this guy for a teacher my life would have been very different. Good job.

[@C.Fecteau-AU-MJ13]

It never ceases to amaze me how not only is a valve train capable of doing that so fast, but with proper maintenance it can do it for such a long time... My 2000 AU Ford Falcon ute (Australian pick-up basically) for example has done 510,000km and she still functions like the day it left the factory, never uses a drop of oil and gets the same fuel economy as it did new. It's never, ever let me down, not even hinted at it. And I use it tow and all sorts, so it doesn't live the easiest life. That intech in-line six is the definition of a workhorse, a truly great example of engineering the right tool for the job. Sure she's well looked after, but it amazes me every time I turn the key and it works perfectly. It's one of those cars I bought as a cheap work car stop gap and now I never plan on letting her go, BEST car I've ever owned. Even more reliable than my 70 series TDV8 LandCruiser, which has let me down twice and cost ten times the money I have into old Ford. Now that's reliability.

[@Low760]

Yet Toyota advertise on reliability. It's pathetic

[@C.Fecteau-AU-MJ13]

@@Low760 Yeah don't get me wrong, the 'Cruiser is an absolute beast and I have it because I use it for going places the Falcon just can't... But she hasn't been the most reliable thing and my word is she thirsty when you ask her to work. It can chew through the 110l tanks in an eye watering amount of time. I have it because there's not really anything else out there that can do what it does, but I could sell it if I didn't need it. I don't absolutely love it. The Falcon I have because I absolutely love that old thing. I'm gonna rebuild the drive train and put a turbo on it when she finally does let go, or the clock hits the full million. Whichever comes first. Probably the former at this rate. We'll do a 10 second 1/4 mile sleeper build, leave the outside looking all weathered and worked, but give 911 Turbos something to think about lol. Ya know what I mean. But no Barras, everyone swaps out the intechs for Barras. The intech deserves so much more love. Edit: I mean probably the latter at this rate. I think it'll go the full million.

[@mangomcpoo475]

Up the mighty AU! (I have an xr8 AU ute, it only has 360,000ks though)

[@C.Fecteau-AU-MJ13]

@@mangomcpoo475 It really was peak Aussie engineering. They're never gonna make them like that again.

[@bowez9]

Lol here in states my F150 has 600k miles and is the same reliable. Not bad for a 60 year old design in use for 30+years. Long live the 300.

[@maxcactus7]

Not sure where you went to engneering school, brother, but if you ever get tired of content creation, you really should teach at a major university. Your enthusiasm and ability to explain things clearly and make challenging topics easy to understand is just fantastic! Definitely the best automotive engineeing channel on the interwebs.

[@stevenwilliams1805]

True but, the Internet is subverting just about everything the university can do except accreditation. Plus universities are starting to lose respect as costs continue to rise with the number of graduates who can't, or won't, find work to repay the debt.

[@lars9168]

@@stevenwilliams1805 I guess engineering graduates will be able to find jobs.

[@Part-TimePro]

Why would you want him to shift from teaching in a super informative, free way to instead a way where the people learning are now paying him directly rather than KZbin paying him, they're less engaged with it since its being taught in a university setting, and he now loses freedom in when to work/make content? Formal education isn't everything, you can learn A LOT from the internet.

[@geneharrogate6911]

Pretty sure he had a high level government job before starting YT. Don't believe he ever studied engineering formally. Certainly shines as a communicator.

[@DESOUSAB]

@@Part-TimePro As someone prone to hyper-focusing on a new interests/hobbies every 4 or 5 years, the internet has been my go-to for theory, practical knowledge and "know-how" over the last 30 or so years. It has always felt like such a special time to be alive. However, I have noticed over the last few years that quality content, where you come away feeling like you have learned something, is getting HARDER to find, not easier. Where once platforms like KZbin were primarily about sharing information, my sense is that today it is more a side- or main-hustle for "content creators." Everything changes, and I accept that - but the focus on likes, clicks and views, as opposed to the an honest and good faith sharing of knowledge, is both sad and sick. But perhaps it is just me on the cusp of pre-senile decay, howling into the digital ether... but, I don't think so. Not yet, anyway...

[@mikevee9145]

I brainstormed this idea in the early 00's. I couldn't find any info on this being done and I thought I had a unique idea, until now, thanks for shattering my dreams.

[@MaNNeRz91]

I did the same 20 years ago in the shower for automatically folding rear wings and front aero that alters drag depending on cornering and speed like Ferrari did 😂😂😂 not even making it up I was only a kid with a cast model of a Modena

[@jonde3]

Relatable

[@hailholyqueen]

I feel your pain. - Bill Clinton 1994.

[@dewaldsteyn1306]

😂

[@bruzote]

I follow the general rule of thumb that if you can think about it, others before you have as well. Such thinking won't lead to me feeling hopeful of inventing something, but certainly got me looking up existing patents any time I thought my idea was a winner. I did have an idea for an unpatented idea at one point, but I realized it would be difficult to enforce and not that profitable for companies to implement. So, that was it. I can't even remember what it was, but it doesn't matter. It's very hard to invent something something valuable AND unpatented AND original (not found in "prior art") and then profit it off of it. If it's a big money idea, people will spend big money ripping you off and defending themselves from your protective lawsuits. That's if you can even afford to sue them.

[@johandonkersloot7031]

Minerva, an old belgian car manufacturer, made valveless 4 stroke engines. At first they made it with double cilinders,, one was moving at half the speed off the pistonopening and closing openings on the side off the combustion space, for inlet resp outlet. It used quite some amounts off oil, so when that car passed bye, you always saw blue smoke coming from the exhaust. BUT their latest model was supposed to get ROTATING valves. It was V8 engine. They also replaced the crankshaft with a solution to get rid off the secondairy (un-)balance . It was made, and it drove around, and the car had a great design, very modern and low, for that time, way more modern as any car, in my humble opnion, back in the day . We speak 1939 tho. The engine (a v8, with 1 long rotation valve for each row off cilinders) was no succes, because the rotating valve's bearing turned out to be not as easy as thought. I thing I remember to have red it was the carbon, from the exhaust, that was supposed to grease the rotation valve, but the 2 long valves were kept in place with wedges, these turned out to be quite a problem they not got solved. So they closed the factory, I guess they had run out off money and or the outbreak off ww2 saw their clientele disapear, Minerva made very expensive cars for ppl that had more money, then they could carry.

[@blar2112]

My grandpa worked at Bultaco for most of his life, they experimented with 4 stroke engines with rotary valves, iirc they never made a production engine because of sealing issues and burning a lot of oil

[@ModelLights]

' because of sealing issues ' Exactly, hard to beat the 'tends toward self sealing on pressure' action of standard valves.

[@talyrath]

It seems like you have two choices. You have a rotary valve that is sealed by a layer of oil, which gets burned by the engine and increases emissions. Or you have a rotary valve that seals because of tight tolerance, which means high frictional losses (greater than the valve springs) plus decreased service life. This seems like a great option for a race car that gets rebuilt every week, not so much for a daily driver.

[@tomppeli.]

Seems like a trend with rotary things in cars

[@d4a]

Bultaco was super cool!!

[@blar2112]

@@d4a Im currently restoring my dad old Streaker with the watercooling kit my grandpa and dad made for them, the kit parabellum. Its so cool to works on those old bikes and see how stuff evolved over time.

[@martincockill1910]

As a 77 year old who first rode a motorbike at 16 and have since carried on with motorbikes and cars also buses and trucks.this amazing man is the best expert on engine's of all types and his knowledge and the way he explains everything is great

[@James-s6b4g]

I totally agree 💯

[@steveletson6616]

It was boring for me, nothing of value that I didn't already know.

[@Riskbreaker_Riot]

Ok Steve. I like your channel btw Steve. Super full of your all knowing knowledge

[@kirinoa]

it sounds awesome because the video is totally, surely, 100% unbiased lol

[@samawalaladawi3955]

I did my Masters degree in university on Rotary Valves engines . Not only do they breath better, but their volumetric efficiency bandwidth is wider, meaning there is no need for variable valve timing for normal road going cars or even high rpm race cars. They work best with any forced induction. A small 1.5l engine could easily achieve 500kw (670 hp) assuming the engine can handle it. Also since there is no piston/valve collision risk, the valve timing could be much more aggressive.

[@Adscam]

40 and 50 years ago they had trouble with the rotary valve binding up due to the combustion pressure. How do they overcome that now, if they could?

[@samawalaladawi3955]

@@Adscam there is something called floating valve seals, they basically float between the head block and the rotary valve, the more the pressure is the more force the floating valve seals. A special film coating is used that has amazing anti-wear properties. Thus these two solutions help eliminate valve expansion and seizing.

[@billshiff2060]

I'd like to see the full airflow vs duration curve. Obviously it will flow well full open but what does it flow part open, which is most of the time?

[@ronfox5519]

Am I mistaken to believe that there have been several sleeve valve engines in production? Mostly for ships or stationaries, but also a couple of warplanes and such.? I was under the impression that sleeve valves were- up to this point -the most successful alternative system of valving that had been tried, but this comment section leads me to believe that the idea has been abandoned.

[@peterduxbury927]

At 3:39, the statements made do not seem to align with the photographs of Normal / Valve Seat Recession. I noticed this.

[@markwarren2298]

Yes. I also in my University days came across rotary valves. The main ones were the Cross valve and the Aspin conical valve. The Cross valve was similar to the one you featured being a cylinder type valve. I found the Aspin to be theoretically superior to my eye. A vertical cone had a port in the side wall and spun on a vertical axis. This had the additional advantage of favourable combustion chamber shape, with additional combustion benefits of lower octane fuels and leaner mixtures. And as usual, sealing, lubrication and wear were the main issues. However in Aspin's later designs, he had cleverly mitigated a lot them by a non constant rotation speed. During the high pressure and temperature part he would drastically slow down the rotation and then during low pressure phases would accelerate the rotation. This obviously helped to reduce these issues during the most harsh parts of the cycle. The speed differences also enhanced the pulsing effect in inlet and exhaust and hence additional efficiencies could be obtained through tuning these pressure waves. Aspin used planetary gearing to achieve this, but modern implementations would probably use stepper motors. The design was so efficient it was claimed to be able to run on mixtures as lean as 1:23. With modern materials and designs no engineering reason why it wouldn't work now (apart from political and financial!). Maybe sintered powdered ceramic conical valves is the way forward for low expansion properties? LJK Setright did a book "Some Unusual Engines" were he covers the Aspin and Cross valves archive.org/details/someunusualengin0000setr/page/48/mode/2up. See also www.aspin.info/

[@geoffmooregm]

I worked at a company where one of the owners was involved in the prototyping of a rotary valve head. Along with the sealing difficulties, he explained to me that one of the big drawbacks was poor airflow when the opening was misaligned. They were able to improve it by adjusting the shape of the porting, but it was not as good as a poppet valve when it is partially opened. Additionally, when the port and spool was half opened, for example, the fuel and air flow would separate in an unpredictable way. Ultimately, they abandoned it because it was not better than poppet valves and WAY more expensive.

[@benjaminwatson7868]

Literally what I imagined, nice in theory but a huge tell tale sign would be if it made more horsepower, I would love to see that dudes project versus the standard engine because I can’t imagine too much more horsepower than the normal poppet valve we have

[@EverydayNormieMadafacka]

@@benjaminwatson7868I mean I’m also curious but… while the efficiency is the goal for most applications it isn’t the focus of this video whatsoever My biggest take away from it, is that for SIMILAR parameters we can have SMALER engine with LESS parts and thus lighter machine overall with possibly less noise/vibrations but that is said by a company that try’s to sell it so idk

[@RockSolitude]

Yeah it wouldn't be hard to fix any of that tbh. The only legitimate problem still is sealing.

[@MrTL3wis]

I've run a rotary valve 2 stroke. It wasn't much at low RPM, but holy hell, it would run on the top.

[@cirosan28]

I think the "separation" of air and fuel flows in a processed mixture (carbureted) is no longer an issue with injected engines

[@yogibarista2818]

Of course, the other alternative to poppet valves that actually made it into production was sleeve valves.

[@patrickshaw8595]

Yes and they were a huge pain in the ass to make. The sleeve has to ground to size with A DULL GRINDING WHEEL at 10X the power and 100x the time requirements of normal centerless-ground parts like wrist (gudgeon) pins. It was so bad Napier whined to Churchill who whined to Roosevelt who ordered an entire year of the Sunnen Corporation's centerless grinder production (about 2000 machine tools) to be sent by ship to Blighty. The USA had to fight WW2 without the use of the finest engines ever made the C-Series Pratt & Whitney R2800 because of that year without enough grinders.

[@paulcooper9011]

Indeed. Most notably used in the Bristol Hercules engines fitted to the Beaufighter.

[@haku1155]

They kind of remind me of the valves in an opposed piston engine.

[@onkelmicke9670]

A really interesting solution.

[@mikethespike7579]

@@patrickshaw8595 By that time the Brits had more than enough German POWs. Germans are well known for their precision engineering. So, why didn't they get some of those to manufacture the sleeves?

[@kylemacgregor4211]

My thoughts are the same as others. This guy was excellent at explaining things. It's like every word he used was needed and every word that was needed was used. Great teacher for sure.

[@Fridelain]

I found one of the normal ones in the street a long time back, use it as a paperweight, had no idea what it was but admired the machining of it.

[@jamescampbell4334]

Coates Engineering in Wall Township NJ started working on rotary valves back in the 1970s. A friend worked for Coates. They had several 5.0 L Ford V8s modified and running with rotary valves. For clarity on Ducati Desmo service intervals, my 2023 DesertX requires Desmo service every 18k miles. That's similar to service interval for motorcycles with valve springs.

[@georgelane3564]

Coates had plenty of longevity problems.

[@rpm10k.]

The valve adjustment interval on the earlier ones was 6000 miles. VWAG buying Ducati actually wasn't a horrible thing.

[@jamescampbell4334]

@@georgelane3564 For clarity, rotary valves have longevity problems.

[@colombianguy8194]

I checked the valves on my Yamaha R3 at 40k km (24k miles), they were perfect, no need to adjust valve clearance. The service manual says that valve clearance checks are at 20k miles.

[@markg7030]

I remember the building Coates was in. I went there in the mid 70's when it was a car museum. I don't know about now but Coates was there in the 2000's.

[@jadesmith6823]

I'm not a mechanic. I love engineering and science. So many light bulb moments understanding internal combustion viewing this channel. You keep it simple, explain the history and future on everything you produce. Especially the "why" in your channel.. It should be played in every highschool and trade training 🙌 Thank you all the way from Tasmania, Australia 🦘🇦🇺🍺

[@DefundTheFringes]

Yes, he gets to the core of things you know you should have questioned all along.

[@MattPiekarsky]

They're booked solid for videos about choosing genders, and they have no space for math or science anymore.

[@MikeAnderson-uj3oo]

I just discovered this channel today. I'm a mechanical engineer with a licensed automotive technician background. Yes , I'd like to strangle myself some days. Moving on. Very impressed with your presentation of the rotary valve. It was explained in such a manner that the average person interested in such a topic would understand. I don't think my 31 year old daughter with 4 little kids would be even slightly interested. She hates when I talk technical about anything. Very well done sir. I will definitely look into some of your other videos. Thank you.

[@doncahala7326]

Yes, my wife glazes over and says "Uh-huh"

[@montre-moi]

@@doncahala7326 Same here. And they want "more women in STEM fields". Shame

[@carmium]

I did! 🙋‍♀

[@jonc4403]

@@montre-moi What a stupid comment. My daughter is a mechanic.

[@vidard9863]

So, as a mechanic I've got to ask who did what with your wives, because it's clear that you guys have a grudge!😂

[@BulletproofPastor]

You are a gifted teacher. Great explanations and at JUST THE RIGHT TIME, you ask the obvious questions (so why don't we see this better valve?) You present the prize and the goals, then explain the challenges. It keeps us watching to the end. Thanks!

[@russstyczinski]

I have a 1918 "automotive service and repair" manual. With exception of electronic engine controls, there is almost no technology that hasn't been thought of and tried. In that manual, there is a reference to a tubular valve engine, which has long tubes within the cylinder head, one for intake and one for exhaust. These tubes would rotate with passages opening into the combustion chamber timed to allow intake or exhaust into or out of the cylinder at the appropriate time. The tubes are fixed at the end of the head to either the carburetor or exhaust pipe. That book has so many cool innovations that have been lost to time, it might be worth a look for some "NEW" ideas. Especially now with our better metallurgy.

[@ebouwman034]

It kind of makes me wonder how we got to such a ubiquitous engine design. Is the current set up so much better than it outweighs all these other options...

[@JohnSmith-of2gu]

Sounds cool. Do you know the publisher/authors? I'd like to look this cool book up.

[@stanislavczebinski994]

Well - a good example is Mazda and the rotary engine. Many companies tried rotaries in the 70ies and 80ies - but finally gave up as sealing the combustion chamber was an issue that couldn't be fixed with that days' tech. Mazda kept tinkering for decades - and all other companies were like "they never get it to work properly". Finally - they made it. They found an alloy strong enough for sealing the rotor tips. End result: Mazda RX-8. A bit thirsty - but robust and high-revving. Basically the same story was an engine running partly like a diesel and partly like a gas car for maximum efficiency. Mercedes tried it (called Biesel - German for Benzin+Diesel) - and gave up. Not possible. Today - you can buy these engines (Skyactive X) in various Mazda models. Point being: Many old ideas work great with today's technology.

[@russstyczinski]

@@JohnSmith-of2gu I've moved a couple of times since I saw it last. It was copywrited in 1918. It was just by chance that I found it. I will dig through my stuff and try to find it.

[@kevintemmer3893]

Probably was referencing an Elmore. They were one of the pioneers of rotary valve engines.​@@russstyczinski

[@josecuevas8602]

16:56 You forgot to take in a count that it actually takes half the effort to spin the cam shaft. Furthermore, this is due to the camshaft spins at half the speed as the crankshaft, 2:1 gear ratio, cam to crankshaft timing chain/belt relationship. Also keep in mind, that once the valve spring(s) is compressed, their is energy stored in the valve spring pushing against the camshaft that's trying to spin the camshaft. I'm shure you have experienced this first hand when trying to spin a camshaft in a cylinder head. Moreover, this compressed energy storage in the valve spring isn't completely wasted. I'm just giving you something to think about. your fan always.

[@tonyduncan9852]

It is true that some energy is recovered.

[@mircomuntener4643]

​@tonyduncan9852 the vast majority is recovered. The only losses are friction and the inertia of accelerating the valve.

[@tonyduncan9852]

Vast majority? As an answer to _some?_@@mircomuntener4643

[@mircomuntener4643]

@Benzley722 the rotating valve will not have inertial energy loss because the valves do not reciprocate, but will have significantly higher frictional losses fuel to the nature of the seal. The inertial losses of the poppet valve is negligible, particularly when compared to that of the pistons and rods. I included it to satisfy the galaxy brain that would otherwise correct me on my egregious omission.

[@tonyduncan9852]

You made the point I was too lazy to make.. 😎@@mircomuntener4643

[@johnsomerset1510]

Very good description and demo of engine valves and their problems. Yes, the rotary valves always leak because of the necessary clearance to permit rotation but also allow for expansion. A solution is four longitudinal seals on the barrel, as used on Wankel engine lobes, but that introduced a lot of friction and heat.

[@rars0n]

Coates has supposedly been selling spherical rotary valve engines for industrial applications since the 90's. Their oldest patent is from 1990. Their system is callled CSRV, the Coates Spherical Rotary Valve System. They have also apparently adapted it to a few automotive applications as well, but it seems like they stopped publicizing that on their website a long time ago. They supposedly had a small-block Ford engine which could turn 14,000 RPM with the CSRV fitted. I imagine that sealing issues were the main reason they didn't pursue automotive applications further.

[@jasonadamson4693]

The Bishop Rotary Valve worked. One of the design guys, Tony Wallis, did a speaking tour in Australia where he described the challenges he had convincing a manufacturer to actually use it.

[@qoph1988]

Looks like it worked in racing usage... I would still remain skeptical until it sees daily driver use. Wish somebody would take a chance on it, even just for a couple prototypes to drive around in the outback

[@royb.1441]

I'm a gearhead...noticed the collection of engines and model engines in the back ground. Love to see that! Excellent job on the video brotherman.

[@EnRandomSten]

I'm a chef by trade, I don't even have a drivers license... yet I love videos like this. It's super interesting listening to someone talk about something that I lack any real knowledge about and doing it in a efficient and entertaining manner!

[@kevinrice957]

You also might like Munro Live, he takes apart cars and finds the costs associated with each part, looks at design decisions, etc. Tesla is a big focus since they're innovating like crazy, wiith lots of changes month-to-month, tiny things to make it easier to make or more reliable. "The best part is no part" optimization of removing/combining parts is fun to see.

[@dieseladdictryan9511]

I know what you mean. The channel, How to drink, is like that for me. I don't drink alcoholic drinks much but it's fun to see what they come up with. Yes, I know it's not related to the topic of cars.

[@dieseladdictryan9511]

​@@kevinrice957Rotary's are pretty interesting engines. Very simple in concept, but a little finicky in practice.

[@Sperperone]

I theorized this at University in early 90's the problem is that a rotary valve will not seal. The rotary valve on the exhaust is exposed to gasses at 700° Celsius and the alloy will expand accordingly locking itself in the sleeve. You can build the rotary valve small enough to have a the clearance that will avoid to get stuck at the highest temperature but at any lower temperature the valve will not seal causing leakage from the combustion chamber, lowering the pressure and hence the power. Not the mention un burned polluted outside, worse fuel economy. The traditional valve can expand according to temperature, the spring will account for the extra length of the stem, the valve head is conical and conical but with different angle, is the valve seat even if the valve head expand, it will seal against the seat.

[@douglasbaty3097]

3/24/24: Excellent, well illustrated explanation of the advantages and disadvantages of today's poppetvalve valvetrain. As a youngster I owned a Vespa scooter, which was a 2 stroke design that required only a 2% oil mixture. It got over 100mpg too. While it did not have a rotary valvetrain and instead utilized standard 2 stroke side port design, it worked flawlessly. Smog emissions were low for it's time. It cost less to manufacture and had a higher power to weight ratio than 4 stroke engines. Your rotary valve demonstration reminds me of that 1965 Vespa engine. Retired in Sacto.

[@1crazypj]

Vespa two strokes used the flywheel as a rotary valve with carburettor connected to crankcase rather than cylinder as most two strokes using piston to open and close ports

[@geemy9675]

50cc two strokes stayed relevant compared to 4 strokes longer than than for larger capacity because of two major reasons regulations and tuning. (and to a smaller extent 125cc) 50cc was the only way for teenagers to have transportation between 14 and 18 to in many places in Europe. or 125cc 16+ kids love to be independent and have transportation but they also love to race, and go fast. 2 strokes was the only way to have good performance stock (after derestriction) and also to increase performance massively with rather simple upgrades (exhaust, carb). If 4 strokes were given 2x capacity rule like MotoGP got vs gp500, 4 stroke would probably had prevailed sooner. now 2 stroke is progressively disappearing from markets due to emissions. direct injected two stroke was a big thing when it came out regarding mpg emissions and reliability but it was already too late and Aprilia never managed to bring this promising tech to larger capacity engines.

[@geemy9675]

thinking about it, Aprilia ditech directly injected two strokes would deserve an in depth video by @driving4answers

[@jerkojuric6137]

Rotary valves in ICE were very popular concept 60-70 years ago Down Under (Australia and NZ) among motorcycle racers. Latest try was the Bishop rotary valve in Formula 1 some 20 years ago and they had a working prototype going up to 18500RPM. They said that V10 3L engine would be around 75kg with rotary valves design. But as many times before F1 regulatory body made mandatory use of poppet valves and that was the end of that story. The only living project with rotary valves is from some enthusiastic owner of BMW E36 in USA who converted his inline six M52 engine to rotary valves engine and that hybrid engine works quite nice for garage build.

[@longiusaescius2537]

Unfortunate

[@DiamondMinerDJC00]

As usual, professional racing shanking interesting new technologies in the cradle...

[@hiltonmccowage9436]

Raced in Australian speedway in the 60’6

[@grizwoldphantasia5005]

Quite a pickle, Ollie, a tight seal on a moving part. What I like most about your explanations is describing something complicated, so simply, that I can understand it.

I've only just picked this video up and am amazed by the amount of comments in such a short time. I've had a quick look through and nothing is mentioned about Alan Millard's KZbin channel where at the moment he is doing a series on rebuilding the Triumph Nemesis Motor Bike that has a V8 Engine with Rotary Valves. I recommend viewing to all as it it is just getting to the good bits clean up and rebuilding and it is quite surprising how rough the engine has been made. Handmade I suppose and the good ting about handmade stuff is that hands haven't changed much in the last few millennia so handmade stuff is usually still make-able!

[@IhabFahmy]

_One other major challenge with poppet valves in ICE applicatioms: Cooling. Valves have to be hollowed out and filled with sodium that melts (vaporizes?) upon being heated and makes the valve act as a heat pipe, transferring heat from the valve head to the stem for dissipation._ _Also, the camshaft lobe centerline has to be offset slightly from the valve stem centerline, so the the valve is rotated about its axis every time the camshaft opens the valve. This rotation is to prevent hotspots or physical high-spots in the valve seat from wearing down the corresponding spot on the valve head (or vice versa). The rotation equalizes wear on the whole surface of the valve head and valve seat._

[@russbell6418]

Only very high performance exhaust valves are sodium filled. Most valves are solid. Could still be incorporated in a rotating valve. I think the temperature limitation is still at the seals. Your observation that camshafts are somewhat offset is true, but not a necessity. This idea would likely work better with double valve trains, enabling a four valve head with single ignition and duplex injection at the centerline.

[@DMPB-fi2ir]

You will not find sodium core valve in a basic production engine the cost is too high and cooling gain and life cycles payback is not great enough to offset the cost. They are common only in extreme hyper cars/super cars / hybrid racing engines / or cutom builds . As for offset you will never get a true center on center position do to the valve rocker being on a fixed pivotal point the pivot point would itself need to follow a scribe arc - they have over the years tried to address this in various ways so the lobe was followed with an expanding arm so the rocker to stem stayed on center of cam lobe and the end overthe valve stays align using an end shaper like a golden arc . Just the simple geometry of the rocker arm being a fixed solid piece as valve mover the lenght of the rocker arm to stay on center line needs to lengthen so a valve train no mattr how you make it gets complex so he K.I.S.S. process is simple fast dirty set up

[@EnglertRacing96]

@@DMPB-fi2ir most tappets and bucket style, the cam is offset slightly on the lifter to rotate the lifter rather than operate purely i sliding im pretty sure thats what the quote was refrencing.

[@gsilva220]

Both problems solved decades ago, for low or even no cost.

[@trentvlak]

not something I have to worry about on my bone stock 5.3 truck engine.

[@lornetontegode6986]

Great coverage. You didn't mention one large detriment to rotary valves, combustion chamber shape optimization. No matter how thin you make the supporting structure between the combustion chamber and the valve, you'll always have a very odd shape and the valve surface will always drag its exposed (and contaminated) surface into the valve's envelope/cylinder. Poppet valves are very easy to fit into hemispherical, or near hemispherical, chambers.

[@gregrice1354]

Ok, that helps quantify and locate a restrictive condition. Next step, prove that is NOT prohibitive or able to be bypassed or overcome.

[@MrTL3wis]

@@gregrice1354 No, that's not how it works. You have to show a better alternative. No one is saying poppets are perfection, just that they have a lot of qualities which allow us to incorporate them into the overall design. It would be a little silly to start our exercise by attempting to prove a negative.

[@manxdr21]

In plumbing, for potable water, it is like a ball valve versus a rubber washer type. Another great informative video. Great job, as always!

[@mannyc4123]

Thank you. You're a natural teacher. Don't ever stop.

[@alanhat5252]

M.A.N. & many others experimenting with rotary valves found that rotating them the other way improved sealing & thus wear compared with the valve you show, I believe they settled on a pair of contra-rotating discs with ceramic faces though this led to a portion of the cylinder head being excessively thin unless they used the valves _as the cylinder head_ thus magnifying sealing issues again & requiring a gap in the side of the piston crown for the injector which led to wear & sealing issues in the bore.

[@bigboy9693]

There is a company in Australia called Repco, back in the day they built a very successful formular one engine, the Repco Brabham engine. If I remember correctly, they made a aftermarket head for a red Holden engine, a very popular engine for modification, it had a rotary valve set up, but it was not reliable due to the expansion as you stated, the company had the ability to build a formular one engine but could not get the head to work reliably.

[@Low760]

Didn't know about the rotary valve from repco but have a family friend who was a machinist from the 70s on at repco. Besides you can get lots of power from a well designed head working around the valves.

[@bigboy9693]

@@Low760 I don't think it went into production, I saw the head in an old Australian hot rod magazine under development and it made excellent power, it could have even been for a grey motor.

[@EverydayNormieMadafacka]

I wonder… with today’s computers could it be possible to just heat the sealing? Like preheat so it would expand and computer would keep it cold enough not to break

[@BretShell-hp9ng]

@@bigboy9693 yes I remember seeing prototype open wheel car barrel valve set up. Late eighty's maybe not good on time. The sound was music to me very crisp and grumpy. This is first time since then I've heard this set up talked extremely proud of you cats thank you

[@RockSolitude]

@@bigboy9693 it never went into production. It was an F1 engine only and they made several iterations, all of them V8s from what I understand. Used in the 1960s.

[@mikecrane2782]

Historically they have been rotary valve systems in the past, Aspin in 1939, before this Crossley Brothers in 1886, even Roland Cross in 1922 to name a few. Some of these have been revisited since and with advancements in metallurgy, sealing tech and bearings have become more viable, and I think ceramic coating of combustion parts would make an improvement to their temperature tolerance.

[@howardosborne8647]

The Aspin conical rotary valve is an interesting concept. I have an old mechanical book covering it in great detail. They even produced a flat 4 aero engine with the Aspin valve system fitted.

[@vilhelmwereen1406]

Clicked to hear a lenghty argument for why rotary valves in german trumpets beat piston valves american made ones… but instead learnt more about engines and motor history than I ever knew before. Great video, brass musicians beware. One thing that peaked my curiosity though is if a system similar to a trumpet piston could work. Where instead of relying on two pistons for inlet and outlet you use one, non-spinning valve that instead moves up and down in the direction of the valve, with grooves cut out ti create different airways depending on the position of the valve. So you would have one piston with 3 states essantially.

[@aurtisanminer2827]

In the 90’s some rotax two strokes had rotary valves on the intakes. They were different than the ones in this video, though. Instead they were a big flat disc with a slot cut out to allow air/fuel flow through it.

[@neilparnell5712]

Yes I remember them, great engines as were the RG500 Suzukis. Rotary disc fuel inlet valves would not work on 4 stroke engines as the inlet port needs closing ''solidly'' e.g. by a chunk of metal. A disc valve which is only 0.7mm thick (Suzuki RG500 spec) would be obliterated under compression / ignition forces. The rotary disc valve works in a 2 stroke because the piston physically closes the inlet and transfer ports for compression / ignition - the combustion chamber has no valves or ports.

[@notsofast2539]

Suzuki has used rotary valves also.

[@neilparnell5712]

@@notsofast2539 And Kawasaki, Yamaha, MZ, Bridgestone, Konig, Aprillia, Cagiva and many more. The rotary disc valve is very efficient 2 stroke system and allows asymmetric port timing - inlet controlled by disc, exhaust by piston.

[@howardsimpson489]

The disc valve is only working against the intake side crank case pressure, not white hot combustion pressures.

[@neilparnell5712]

@@howardsimpson489 Yes in a 2 stroke as it was designed for . The original thread was replacing poppet valves with drum type rotary valves which would be exposed to combustion pressures. The disc valve just sorta sneaked in !

[@Zatarra48]

Oh perfect! Just as I will drive just shy of 4 hours this evening and then again tomorrow. This brings me right into the mood! I drive a VW Golf 6 1.6L Turbodiesel Frontwheel-Drive Stationwaggon with 298000km but it is super fun to me. I attribute the fun to the horizontal stabalizers and the turbo of course. Heel-Toe Downshifting, Double-Clutching and all other good stuff I learned as of last year. The videos you make deepend my knownledge about the whole drivetrain which makes driving so much more enjoable. Keep up the good work!

[@illbeyourmonster3591]

I suspect that lack of emissions compliance and detuning has a lot to do with it still being reliable, fun and fuel-efficient to drive.

[@Zatarra48]

@@illbeyourmonster3591 Could you elaborate on that? Are you implying the Diesel Affair at VW and others in Germany a few years ago?

[@Den_drummer]

So from what I understand from this video... We've been working towards the local maximum of the poppet valve and now some people and companies are looking into working towards other local maximums (in this case the rotary valve). Neat!

[@Scuffed_Andy]

My father designed and built a rotary valve and used it on a 350cc Enfield m/cycle over 60 years ago. It was nuts.

[@markbrzezinski8889]

Im 64. I drew up a rotary valve engine when I was about 18 years old and sent it to a technology company called Sarich in Western Australia. They were kind to me and told me It would not work. You can actually use just one rotary valve which is both the exhaust and inlet. This helps to cool the valve. A ceramic cylinder is probably the way to go but timing is an issue.

[@adoreslaurel]

Was there not a rotary valve head developed in South Australia? the name Clisby comes to mind back in the 60's,it was a long round piece of metal with flats machined in it that doubled as inlet and exhaust, it sat in half rounds on top of the head, I think that the downward pressure required to keep it tied down [as it became the top of the combustion chamber] may have worked against it as it had to act as an effective seal but still able to rotate and be lubricated in some way, maybe today if retried, emission stands might be a problem. There is something on Clisby if you go to Google.

[@markbrzezinski8889]

I do also remember that. My design had the port going through the rotary valve which gave more sealing between the ports and the chamber. And it had higher compression. Honestly I don't think they will solve the sealing issue and as the rotary valve heats up it will bind too much.

[@Alaska_Engineer]

I built a rotary valve cylinder head for a Honda 90 as my senior project in 88/89. It runs but lubrication and sealing are serious challenges that few have overcome.

[@shifty1927]

I run rotary valve rotax snowmobile engines in all 4 of my 85 honda oddysey fl350s.

[@Alaska_Engineer]

@@shifty1927 - Isn’t the Rotax rotary valve a 2-stroke? I believe Kawasaki popularized this in the 1970’s. The valve described in the video is like the one I made and maintains a 4-cycle combustion process.

[@shifty1927]

@@Alaska_Engineer yea they are 2 stroke.

[@ironken1796]

​@@shifty1927 for 2 strokers, rotary valves have been around for a very long time as mentioned. Rotax and Kawasaki come to my mind as well. But, remember. The 2 stroke rotary valves only deal with the intake charge (no hot dry exhaust), only deal with low pressure in the crankcase before the fuel transfers into the cylinder. Not the high cylinder pressures achieved during combustion. But, I get what you were thinking.

[@shifty1927]

@@ironken1796 Cool and yea that makes sense.

[@johnboyns]

Just discovered your website. I have seldom seen someone with so much talent and passion explaining complex technologies. Thank You and you bless us all with some of your talents.

[@MegaChickenPunch]

Ok boomer

[@LeCharles07]

Omg. 0:25 and you've already demonstrated to me how much power is lost to the valve train. 🤯 Insta-sub.

[@2coolwheels139]

I remember reading about the Knight "Sleeve" valve engine which also overcame some of the drawbacks of the poppet valve system. They did go into production in the 1920s, but that technology didn't catch on for some reason. Might be a good topic for a future video.

[@jbepsilon]

Sleeve engines solved some problems of 1920'ies poppet valve technology, at the cost of introducing a bunch of its own problems. The brits did develop the technology for aero engines, at great cost, but in the end it wasn't an advantage over poppet valve technology of the time and they faded away.

[@darthkarl99]

@@jbepsilon It was a better performer AFAIK, but it was also a giant headache to manufacture.

[@jbepsilon]

@@darthkarl99The Napier Sabre was powerful, but that was because it was a high rpm and high displacement design with a whopping 24 cylinders, not because it used sleeve valves. In fact, the sleeves limited boost pressure lest they deform and seize; the Sabre was never cleared to use more than +11lbs boost operationally during WWII, compared to +25 lbs for the RR Merlin. Secondly, they spent so much time and effort in making the sleeves work even passably (when initially introduced into service, the Sabre had a time between overhauls of 25 hours!!), that they never had time to make a good multistage supercharging system which would have been necessary for good high altitude performance. The Bristol Hercules radial was the most successful sleeve valve engine of WWII and was extensively used in British multi-engine aircraft. However, it was about on par with similar size poppet-valve engines like the Wright R-2600 or the Mitsubishi Kasei, no particular advantage of the sleeve valves there. Due to the time consuming and extremely expensive R&D project trying to make the sleeve valves work, the Hercules was much delayed, and it's big brother the Centaurus missed WWII entirely.

[@drkjk]

Poor sealing with a lot more complexity. @@jbepsilon

[@stephenwestlake7164]

Sleeve valves where heavily used in British WW2 aero engines. E.g. The Bristol Hercules (14 cylinder radial) used in the Wellington - they made 84000 of them. Also the Napier Sabre (3000hp from 37L 24 cylinder) used in the Hawker Typhoon.

[@Mushin-Flowstate]

One of my absolute favorite channels. This was a very clear and concise video, and you explain things like a pro

[@2ane]

seems like a neat idea for single cylinder engines as the barrel can function as a balancer shaft against vibrations as well reducing the needed parts even further.

[@highpointsights]

I've worked on my own design for a rotary valve. I was building a head that would fit on a Briggs and Stratton 5 horse engine. Unfortunately my software couldn't model the gas flow. I was trying to build a mechanism that was capable of adding a dwell in at propitious times so the combustion events could take place effectively.. Been scheming on this idea for 30-40 years. All that to say this is an interesting video. I may pick it up again!! But thanks for the content!! I probably need to study desmodromic valves!

[@KF-bj3ce]

A ver hands on explanation to the problems of rotary valves, so simple yet difficult. Thanks for this loved it.

[@TheRIZKYRAMA]

You should see how 2-stroke vespa scooter utilized rotary valve for its engine. And they are considered mainstream scooters back then. They are unique because they use the crankshaft web for the valve mechanism.

[@robertomalatesta6604]

And Suzuki RG500 as well.

[@kwitwerikok8o863]

​@@robertomalatesta6604and in the 70"s Kawasaki 100cc 2stroke race motorcycle.

[@paulmaxwell8851]

Most of the two-stroke model airplane engines I ran in the sixties, seventies and eighties had rotary induction valves built into the hollow crankshafts. That was the standard then. A tiny handful used reed valves, as snowmobile engines do today. At any rate, the rotary valve did a great job. Of course, being on the intake side, it wasn't exposed to combustion gasses or temperatures.

[@jn904]

Trabant 601 uses rotary valves on the crank webs, too.

[@oskjan1]

Another couple anvantages of the poppet valve: it's sealing surface is self cleaning and the friction surfaces (valve guides) are cooled by the intake charge so oil doesn't cook and gum up the movement.

[@Agualyone]

Heat is also transferred from the poppet valve to the head when it is seated.

[@pastaalalamborghini]

The sealing surface is only self cleaning on port injection engines. Ever pulled the intake or heads on a DI only engine? They get pretty nasty without fuel washing the valves.

[@Ijusthopeitsquick]

The exhaust valve guides aren't cooled by the intake charge.

[@peglor]

@@pastaalalamborghini There's still an element of self cleaning of the sealing surfaces on engines where the valves are allowed to rotate in position as they open and close. I'm not sure whether this is common, but some engines have the valve stem slightly offset from the center of the cam to cause this rotation as the valve opened and closed, which reduces fouling on the sealing surface, though it won't stop things getting gummed up everywhere else.

[@pastaalalamborghini]

@@peglor ...valves that spin themselves against their seats to self clean ... Bye

[@Doug....]

You are absolutely right about the power needed to open valves. It leads to lower power output for sure. Thanks for pointing that out. 🙏🙏

[@davidprocter3578]

Back in the 1970's as a teenager rotary valves suddenly struck me as a great idea to control gas flow through an engine, quickly drawing up my idea fag packet style I rushed downstairs and showed my basic idea to my father. Hang on a minute says my father and takes a book down from the book shelves opening the book and flicking through he stopped on a page and showed me a drawing of an engine using an almost identical system. The book was a fantastic encyclopedia of engines of all types, unfortunately my father gave the book away many years ago and I no longer have it as a reference but as a teenager it really broadened my horizons as to the possibilities many many engineers had explored. My Father had designed an engine himself as a student at Loughborough college in 1947 a twin cylinder two stroke very light weight and compact 250 cc motor cycle engine, instead of a crank shaft the pistons and con rods ran in an orbital gear arrangement, dad later discovered that this idea had already been explored in the previous century as a steam engine. of course the idea was revisited in the late seventies as a four cylinder four stroke engine built in Australia named the Orbital. That to did not take off.

[@turbo32coupe]

These have been around for years. The failure of the design is that combustion gases get around the barrels, kill the lubrication around the barrels and they fail. Sleeve valve engines, which have a vertically aligned barrel, were used in WWII, such as the Napier Sabre, but suffered from reliability issues.

[@hoverhead047]

When you first said rotary valve I first thought of the Saber and Hercules engines of WW2 aircraft but then I remembered these were sleeve valved engines. Then I recalled that steam engines also had issues with rotary valves.

[@jbepsilon]

Steam engine people have a saying "there's two kinds of valves: poppet valves, and those that leak".

[@Poctyk]

Same I was very confised for a moment when he didn't mention those

[@toddmiller5322]

There were some heads designed several decades ago for a Ford 5.0 that used shaft mounted spherical valves. Being as the valve train was the limiting factor on RPMs, this design allowed ridiculously high RPMs and tremendous power output, and greatly increased the intervals for oil changes. Then POOF, they disappeared and you never heard anything about them again.

[@stephenhall3515]

This website is a discovery for me. The straightforward presentation, albeit assuming some knowledge of engines and valves, is absolutely first class. Naturally I have subscribed.

[@oxide7]

You can still use 2 of these per bank. One for intake, one for exhaust. Then you still get to put a plug/injector in the center. I like this idea. It's clever, and with enough research it could be made to work. The poppet valve did.

[@ralanham76]

Yes also you could alter the timing separately.

[@tonyduncan9852]

Just because poppets work . . . doesn't mean that something else will.

[@wackowacko8931]

A company in the late 80s and early 90s was trying to make rotary valves that were supposed to go into production vehicles if they could get all the issues ironed out. The big three were apparently interested. It was called "Coates Spherical Valve System" or something similar. Their main issue was also sealing the valve to the combustion chamber. One advantage of the system was that it had an inherent advantage in boosted applications. Rotary valves have been around a long time in various forms, a nice idea to implement if the main sealing issue is figured out.

[@qphase49]

Use dual, smaller barrels to ease location issues. I'm 75. When I was a senior in HS I spent a year with an 80+ year old man who had been a factory authorized "Knight" engine mechanic for Willys. I learned to reman the engines and it was fascinating. The dual sleeve valve design had some shortcomings but, it had some advantages too.

[@lanzer22]

Studied mechanical engineering decades back, engineering challenges are fun but ultimately an electric motor just makes so much more sense than building 20 things to overcome 20 other problems that comes with burning fuel. We have a big radiator, systems to enhance aspiration, systems to deal with timing of combustion, a whole lubrication maze with the need to replace oil often, countless moving parts and the need for everything to work in concert.

[@eDoc2020]

I think the electric motor is the future for main propulsion. Combustion engines will likely remain as range extension generators. AFAIK if you always run at one RPM and one torque many of the difficulties are eliminated.

[@argh100100]

Absolutely true, but electricity has other challenges. Mainly that it can't be efficiently transported. And at this point, storage is also not ideal.

[@lanzer22]

@@eDoc2020 yeah the whole deal with needing a transmission is another big deal. Though I think for extending range there might be better solutions such as using hydrogen to generate electricity than gas with an engine. Though time will tell.

[@lanzer22]

@@argh100100 energy density is always gonna be a challenge, only future solutions can come remotely close to fossil fuels. Though at this moment a car that has a 300 mile range can fit the bill for almost all consumers living at home and that’s a great start.

[@eDoc2020]

@@argh100100 What do you mean electricity can't be efficiently transported? I would assume you meant it can't be stored easily but your next sentence was about storage.

[@Dave5843-d9m]

Direct inject two strokes are very clean. They don’t have fuel washing oil of cylinders and bearings so can run a much smaller oil flow. Fuel is injected after all ports have closed so there’s never any unburnt fuel going down the exhaust. Exhaust power valves maintain midrange power and there’s no partial combustion to slap the piston around - much less bore wear. The Rotax ETECH is cleaner than competitors four strokes and has better fuel consumption. It can use stratified charge solving NOx issues. The pre combustion chamber used on F1 engines is an ideal fit as the excess air can be varied via inlet valves.

[@shifty1927]

The rotary valve I'm used to is from the rotax engines. Its just a flat disc with openings that sits over the intake ports and rotates in time with the engine. Surprised rotax engines weren't mentioned.

[@garycarbonneau499]

Also the Rotax engines make more power per displacement do to intake timing advantages.

[@shifty1927]

@@garycarbonneau499 yea I use them to swap into the old honda oddysey and pilot mini buggies. Currently running a 670 H.O. that makes around 140hp. Always joked that I have the largest collection of snowmobile engines without ever owning a sled. Have a wall of 583,617, and 670s just stacked up. I'm in Southern Maryland we barely get any snow.

[@stevehead365]

This is for the intake valve on a two stroke, the valve is not subjected to combusion pressures and temperatures, it would not work on a four stroke.

[@m3chanist]

The energy used compressing a valve spring doesn't just evaporate, it is stored as you noted, and that stored energy goes back the way it came when the valve is closing. The sealing challenge in a rotary valve cannot be overstated, I led the design of a "novel" rotary valve system for a different application, one with far a narrower temperature dynamic range, differences in the expansion coefficients of the metals used multiplied by the necessary tolerances ultimately killed it as a viable system, at a reasonable price point, I.e. without going to exotics. At one end you have sloppy seals and at the other you have tight seals and fast wear. If the temperature was static however (which would have involved a stabilisation/preheating phase prior to operation) or sealing efficiency wasn't critical, then sure. I'm also a kiwi as it happens, we like our unconventional approaches down here, but we are also pragmatic ;)

[@jamescampbell4334]

This comment needs to be pinned at the top. Having spoken with a friend who worked for Coates back in the 1980s and 1990s, these were the same issues they were facing.

[@rockyblacksmith]

"it is stored as you noted, and that stored energy goes back the way it came when the valve is closing" Well, not exactly. Look at this as an equasion: C - the energy stored in the spring at full compression A - the energy needed to move the valve assembly B - the energy fed back into the cam shaft L - losses to friction Put the energy supplied on one side and the energy expended on the other, and you get this equation: C=A+B+L. Now, C is constant and L is ideally kept to a minimum. But what happens to A when the RPMs go up? Since the valve assembly has to move faster and faster, more and more energy is needed to overcome its inertia (as it is constantly changing direction). That means A goes up. And since faster motion usually also means greater friction losses, L goes up too. Meaning that B, the energy going back into the camshaft, goes down rapidly. And the higher the RPM go, the smaller the energy feedback.

[@m3chanist]

@rockyblacksmith the energy required to overcome inertia does increase yes, but that energy is present both as input and as output, the only loss is due to friction . And there are no frictionless bearings in this universe, regardless of mechanism.

[@rockyblacksmith]

@@m3chanist The input does not increase. The energy stored in a fully compressed spring is a fixed value. No matter how much energy you try and put in, it will only ever give out that amount. That is the basic physics of springs.

[@m3chanist]

@rockyblacksmith Input: "more and more energy is needed to overcome its inertia" it seems you don't understand your own words, or do you now disagree with them as well? Output: Momentum is conserved, including angular momentum, your B, rather than it "going down" as you claimed, the amount of momentum increases as more energy is fed into the system, the mass of the parts multiplied by their velocity, as their velocity increases so to does the momentum as the mass is constant, obviously. All that goes in comes out in a reciprocating system, apart from the friction, the input energy is stored and returned (minus the frictional loss which is a given for all devices). If you'd like to make a claim for a mysterious black hole of unbalance that is swallowing the system's total energy somewhere else, then be my guest, I'll get my popcorn and inform the Nobel Foundation. What is more, a rotary valve has vastly more contact surface area than a poppet valve, frictional losses are orders of magnitude worse.

[@youtubasoarus]

Interesting idea. It's strange too because that wasted energy in actuating the springs could be greater engine efficiency. But right, once you see the size of the rotor assembly @11:11 you understand why it's not used. In a 4cyl it would be a hell of a lot of mass + wear and so on. Just costly to run and manage. Awesome idea though. A V8 with 8 of those cylinders trying to keep the cylinders sealed? Insanity. Like you said with the poppet valve, it self seals and the more cylinder pressure, the better it seals. A necessary evil I suppose. Edit: One critical issue with that design would be that the initial cylinder installation would achieve its best sealing characteristics and would only get worse over time as cylinder pressures act on it and make it out of round. That would of course cause sealing issues and loss of pressure (loss of power) at some point. It would be incredibly difficult to engineer a solution to keep that cylinder from being destroyed in not a lot of time. Lastly, a critical failure point could come when the cylinder becomes so out of round it seizes in its bore and causes the engine to explode or seize itself (cannot exhaust gasses). Sadly, poppet valves have everything going for them in this regard, cheaper, easier to maintain and manufacture, install, better service life etc...

[@nytsamlegt]

Actually you get some, if not most, of the energy back when actuating the spring. In large two stroke marine diesel engines, which are actuated using hydraulics, there is significant loss in actuation energy compared to the old ones that used camshaft.

[@youtubasoarus]

@@nytsamlegt Hmmm interesting. Another win for the traditional poppet valve 👍

[@OldSchoolZ-wy2yx]

Wankel engine rotors prove that rotary valves could be made to work. Engines are already required to be maintained by some x amount of km, an added few hours and a few hundreds $ in seals, 2 or 3 times in the course of 450k km is more than worth it

[@wildbill6976]

@@OldSchoolZ-wy2yx 'cept your wanker engines burn so much oil that they can't pass emissions testing, and cost more to rebuild when they fail than just replacing it...

[@Ijusthopeitsquick]

The failure mode you describe would be less catastrophic than a conventional valve train failure, since a seized rotary valve won't fall into the cylinder and ruin the whole engine.

[@ZeroXSEED]

People who regularly deal with plumbing know how difficult sealing rotary valves can be....

[@custos3249]

Not really. That problem is just a sad reality behind the lazy engineering of legacy, "good enough, so why change" systems. If someone without an engineering background can build a custom house that swivels using custom joint seals for plumbing designed for easy maintenance less often than you'd need to reshingle, "real" engineers don't have any valid excuses.

[@ModelLights]

'how difficult sealing rotary valves can be....' Exactly, that was my first though off hand. Poppet valves are reliable, most engines last 200K miles etc, pressure makes it want to seal instead of blowing by gaps, and so on. If rotary valves were really better, everything would already be rotary valves. People in the 1930's, 40's, and 50's were geniuses and then some and trying everything. Rotary valves would have taken over ages ago if they were better.

[@madeconomist458]

I'm not sure the analogy works because we are dealing with air flow, not liquid, and we don't need a perfect seal, unlike in plumbing where a perfect seal is required.

[@ModelLights]

@@madeconomist458 Air is worse than liquid, not better. ' and we don't need a perfect seal' And you'll be cooking the oil needed, a very bad idea. It is not 200K mile reliable tech.

[@DrTheRich]

@@madeconomist458 "we don't need a perfect seal" that doesn't even apply to my 1930s lo compression cast iron flathead model a with only 40hp and 2200 max rpm... I have leaking valves, and a significant drop in the little horsepower i have... Even more noticable in the loss of torque. The thing is, that yes, with poppet vales, if your seals aren't microscopically perfect, the pressure from the combustion will press them shut anyway. But with rotary valves, this benefit is lost, so the higher the compression the worse the leakage

[@alrichnolte1680]

Informative and entertaining as always. Keep up the good work, these videos have some of the best information available on engine tech and are an absolute blessing to engine heads everywhere.

[@matthewstorm5188]

I can see quite a few issues with rotary valves. - Lubrication. You’ve got a rotating cylinder that fits tightly in a housing and which passes air/fuel mixture into the cylinder and exhaust out. How are you going to lubricate the thing without sending oil into the cylinder and exhaust out? - Contamination. As was shown here, carbon deposits form on the rotating cylinder. This can be a problem as it can cause wear and possibly cause the cylinder to seize within the housing. One advantage of poppet valves is that they are fairly self-cleaning in this respect. - Combustion chamber geometry. One nice thing about poppet valves is that they form fairly well to the combustion chamber. They create no severe discontinuities or indentations in the combustion chamber. But due to their geometry, rotary valves are going to create a much ‘messier’ combustion chamber. - Less flexibility with variable valve timing. You are pretty much limited to simple valve phasing here. Changing duration would be MUCH more difficult.

[@MihaelTurina]

If I had absurd amounts of money, I'd invest heavily into obscure engine technologies like this to try to improve and save ICEs. Sure, many of these are not widely tested and may have unsurmountable problems, but we will never know if all the money goes into making electric cars.

[@deborahchesser7375]

Sachs used a rotary induction for years, I always thought about adopting that system on a 4 stroke engine. A spinning valve doesn’t have to reverse direction or slam against the seat. I just didn’t have the millions to develop it.

[@tonyduncan9852]

Then you're lucky. They say that if you want to make a *_small_* fortune, then spend a *_large one_* on rocketry or aviation. (Or rotary valves.)

[@deborahchesser7375]

@@tonyduncan9852 that’s true, the best way to make a million? Start with two. Honestly if I had a couple million the only thing I’d develop would be some acreage.

[@raoulrr]

@@tonyduncan9852 How much do you think the collective auto industry has spent on refining poppet valve tech over the past 100 years? Even the total loss lubrication engines from 100 years ago had more development time & money in them than the rotary valve tech has today (and those old engines had nothing to do with words like "reliability" or "maintenance intervals")

[@tonyduncan9852]

Hey, I'm no accountant (calculators work so well don't you think?), but I AM an 80 yr old aerospace engineer who ran and tested all manner of heat engines, compressors, turbines, reciprocators, etc., more than 60 years ago, at research establishments in the UK. We also studied tribology, etc., but not, as it happened, rotary or sleeve valves. But I DID receive good advice, which I am passing on. Namely, do not go there. *_Except for specialised situations,_* ICE engines are a waste of time. Billions of them are destroying our future as we breathe. @@raoulrr

[@deborahchesser7375]

@@raoulrr exactly, engineers have had many years of R+D to study the subject so if there were a better alternative to poppet valves they probably would have been implemented. Apparently, reduced flow around the valve and parasitic loss from the valve train are minimal enough to negate a different and possibly more complex design.

[@TigerRacingProducts]

Wait... Coates CSRV Coates Spherical Rotary Valve solved the sealing issue. They were located in New Jersey usa. They also had patents and running test engines and bikes. We know because we delivered one bike to their shop many years ago. Afterwards, I saw the videos of it running with one of their heads. So what happened to them?? Literally stopped back, and doors were locked. No phones worked. I'm very curious if anyone knows what really happened to them? They were working on big deals with manufacturers. Look them up. Look up the videos. It was the real deal.

[@alexmanojlovic768]

Love how succinctly he pointed out that so much of modern ICE development is to get round the problem of the poppet valves.

[@BudgeChem]

Great content. I love the idea on rotary valves. Sadly, I am skeptical. I had been eager for Coates Intl to disrupt with world with their ceramic spherical valve engine since 1996. I guess they never gathered up enough unobtainium to make headway.

[@shifty1927]

Rotary valves have been successfully used in millions of rotax engines. They're not a rotary barrel design though.

[@aaceytuno]

I see, Drake doesn’t like the “old” valve design that is tried and true, he only likes the new younger valve that is unproven. 😅

[@baseder514]

7:43 I did NOT hear that valve fall. where did you throw it man? WHERE DID IT GO???

[@jayartz8562]

An ordinary man of ordinary strength just launched a valve into orbit.

[@rasky1991]

Don't worry it fell straight into one of the Bugatti W16 cylinders and did something funny to the engine.

[@minidreschi2]

@@jayartz8562 man, i love the comment section sometimes :D

[@Astrosisphere]

@@jayartz8562 It'll come around and hit him in the back of the head when it hears what he was saying about them!

[@DrTheRich]

The backrooms

[@redhead1804]

Mr.Merritt Zimmerman used rotaty valves in motor cycle racing in the 1950's. It had a lot of power and won races. He was always trying to improve seal life and had some oil comsumption problems. As a small shop, he did not have the resources to continue the developement on the concept. The engine had a lot of bottom end torque and a very high rpm range ( I believe rpm limit was 14,000). I believe it was silghtly over 2 hp per cubic inch in 1955 on a 4 stroke engine. Which was incredible at the time.

[@kentporter2991]

Smokey Yunick, an outstanding NASCAR builder and inventor, was building a tube style’valve’ system, many years ago…! 👍🇺🇸😎

[@bottlapivo]

I wish I hadn’t thrown away the mid ‘80s Popular Mechanics issue which featured Smokey’s ‘84 Pacer with his “advanced fuel atomization system” that produced 60 HP per cylinder while achieving 80 mpg or so. I think the article went on to say that one of the big 3 bought the idea from him and shelved it. He was also working on an all-ceramic design with no cooling system. The guy was a genius.

[@jamesgilbert124]

At just after 7:00 in he performs a magic trick. Not "Making the valve disappear," which is easy, but "Making the valve disappear without immediately hearing the expensive and fragile thing it just flew into shatter."

[@askquestionstrythings]

This valve seat recession issue which drove the use of leaded gas is still an issue with small planes that still use leaded gas. A pilot school recently tried to switch off leaded gas for their small planes; and found they had major valve seat recession issues resulting in the need to switch back to leaded fuel for their small planes.

[@tonyduncan9852]

There you go.

[@oscar_charlie]

They didn't do a double blind controlled experiment on it, though, so no sure way to know if it was the fuel or a material problem or the way they operated those engines. Plenty of those engines have been operated on unleaded pump gas over the years with no reports of valve seat errosion.

[@tonyduncan9852]

That would depend on their duty cycle. Consider that. @@oscar_charlie

[@askquestionstrythings]

@@oscar_charlie The investigation into the University of North Dakota’s recent issue with UL94 is ongoing. maybe it's all related to the Lycoming engines that power UND's fleet of Piper PA-28-181 Archers and PA-44-180 Seminoles.

[@SuperFunkmachine]

Small plane engines have been frozen in the past for decades, useing old designs from the 50's that where barely improved from the 30's ones.

[@gofres_8540]

The thing I love most about this channel is that it confirms that all the crazy ideas I had about engine design back when I was a student were dumb and already tried and failed by others 😂

[@svntex6440]

Thanks for these understandable videos!

[@demetridar506]

What most people do not understand, including our presenter here, is that the energy spent to compress the valve spring returns to the system when the valve closes. The overall frictional losses of the poppet valves are not significant. The main issue with the rotary valves is hydrocarbon and particulate matter emissions. The reason poppet valves are used extensively is because they work, and they work well.

[@benjiwiebe8128]

And not only can you even see the energy returned in the first bit of the video (the camshaft springs past where has has turned it to), that's happening with a dry engine. When the engine is running there's a continuous film of oil on the cam lobes and things are very smooth. And if they aren't, you're going to need some new parts real soon. Source: am mechanic.

[@rockyblacksmith]

"is that the energy spent to compress the valve spring returns to the system when the valve closes" What seem to not understand is that compression energy and kinetic energy work somewhat different from one another. The energy transfer you describe is at its most efficient when the rotation of the cam shaft is extremely slow (and even then it has losses other than friction). But when the RPMs rise, it gets less and less efficient, because more and more of the springs energy goes into its own acceleration and that of the valve and rocker, and thus not back into the camshaft. The phenomenon of floating valves happens because the cam rotates faster than the spring can move the valve back into place. I hope it goes without saying that in that state, when the rocker actually looses contact with the cam, the spring imparts NO energy back into the cam shaft. And the higher the RPMs go, the closer to that situation they get, meaning the energy feedback gets closer and closer to zero. For an analogy, imagine trying to push on a moving object: If it moves a lot slower than you can move, it is easy to impart energy on it. The faster it goes, the less energy you can impart. If it moves at or above your maximum speed, you can't put any energy into it at all. Same goes for the spring (which has a fixed maximum speed) and the camshaft.

[@demetridar506]

@@rockyblacksmith You are not entirely wrong. As you increase the rpm, there is more energy lost inside the valve spring themselves. Its called "hysteresis". But it is still not a major issue. It is relatively easy to measure valve train friction. That measurement takes into consideration more or less automatically of all these factors. It does not account to much. And in fact, it diminishes some with speed because the lubrication improves some (I am talking about flat cams, roller cams have even less friction). Valve float is a different matter, engines should not operate in that region. The point here is people assemble engines and feel the drag that the valve springs apply, and intuitively think that valve train friction is a bit deal. It is not for the reasons stated above. Piston friction is the big deal, once you add the gas pressure when the engine runs.

[@rockyblacksmith]

@@demetridar506 I'm not sure where exactly in the spring a hysteresis behaviour is supposed to occur or rather, of what kind. There are hysteresis phenomenons in plastic deformation, but the whole point of a spring is for that NOT to happen. But regardless of that, you are not adressing what I said. I described a physical process that dictates that there MUST be a loss of energy between them. Now, if I am wrong, feel free to point out the error in my physics. If you want to make the point that the energy loss is neglegeable even at the maximum revolutions of a given engine model, then feel free to give me the math for that.

[@demetridar506]

@@rockyblacksmith There is some loss of energy, sure. Most of it is via friction in the follower cam interface. I am sure some takes place in the valve spring since there is heat buildup (valve springs get hot and are cooled by the flowing oil mist). What I am telling you is that there are numerous measurements of the total energy lost in the valve train. They are about 10% of the total frictional losses. By comparison, the piston assembly can be way more than 50 % of the total friction under load.

[@VykronianF1]

They will never do this, but if F1 wants to be the “pinnacle” of Motorsport and still relavant to road cars they need to do this and efuels/ reuse millions of engine blocks and heads from the junk yards around the world. They never will but we can dream.

[@Ocean_breezes]

Love this guy. He casually flings the valve while talking about the rotary valve. Informative and entertaining

[@court2379]

The valve cylinder should be tapered. Then as thermal expansion happens it can slide out a little bit and still maintain the same clearance. Also a linkage drive may be a better design. Then you can have it move in a nonlinear speed. Open quickly, dwell a bit in the open position and close quickly. A second link can be added to accomplish variable timing. I struggle believing this will actually last. The automotive manaufacturers have s done a lot of research. Many crazy designs have been tested, and surely this one has too. The patent must be a design patent as this idea has existed for about as long as engines have, and sime steam engines used similar. I would guess it gets fouled up with combustion products and tiny amounts of dirt that make ot through the filter.

[@tonyduncan9852]

_"The valve cylinder should be tapered"_ - Poppet seats already are. The complexity of non-linearity is *_heavy._*

[@court2379]

@@tonyduncan9852 I am not talking about poppet valves. And nonlinear movement is easy with a simple four bar linkage.

[@tonyduncan9852]

Just design in that 4-bar linkage, and then tell me it occupies less space, and weighs less. Thanks. @@court2379

[@JukkaX]

Two Stroke for the win. Thank u for the fine lecture once again.

[@tonyduncan9852]

Two stroke for the extinction of humanity ?

[@JukkaX]

@@tonyduncan9852 Why not.

[@tonyduncan9852]

Because Life. @@JukkaX

[@jpbsv]

Great content, as always.