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Rotary Valve Cylinder Head Prototype

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goldenfab

Proven Member
38
51
Nov 16, 2016
Dewey, Arizona
Hi All,

I'm new here and new to DSMs but am a long time gear head. I would like to share a project that is a long time coming...

This all started back in high school. A buddy of mine had come across a company that had a design for rotary valve heads for a small block ford with some impressive claims. I always thought it was pretty cool. Years go by but I never forgot about it and periodically spent long hours searching the end of the internet looking at rotary valve head designs and checking on the latest developments of that company. I then go to college for an engineering degree and managed to talk the school into doing a directed study for which I would design a rotary valve cylinder head for credit to satisfy some technical elective credits for my degree. I went out and bought 4hp horizontal shaft engine and designed a cylinder head for it. In another class I designed and built a engine test stand dyno for the engine. I worked in the student machine shop at the school and was able to get most of the machine work on the new head design done but was not able to get it finished before I graduated. After graduating I bought a used small Grizzly knee mill that was converted to CNC and a manual lathe. After much work I had a prototype that started and ran but left much to be desired. During this time I exchanged some emails and phone calls with the company that had the rotary valve head design. I was very interested in being a part of bringing the technology to market and eager to work with them. I told them I wanted to see a working prototype I could test out and they were not interested in that. They told me non-exclusive US only patent rights was going to be on the order of several million dollars. After a few more emails with them trying to get them to work with me I gave up on them. Personally I think the whole company is a scam but I was still intrigued by the idea of rotary valve. I then changed direction in occupation which landed me overseas for a year during which time I had no shop to work on the new prototype. Since then the patents I was interested in expired so I figured game on! My plan was to work on the small engine some more or go straight to doing a car engine. Two different co-workers I made friends with convinced me the 4G63 engine would be a great candidate for such a design. I took their advice and bought a used head off of ebay and spent the next year drawing up the stock head in CAD and the new rotary valve head design.

Fast forward a year and I got back to the US and started setting up a shop. I built a furnace and started learning how to cast aluminum. bought a full size knee mill I converted to CNC that was big enough to do the machine work for the new head design. After tying to balance a marriage and a long commute to my day job and long hours as an engineer I convinced my wife to take a year off from work to work full time on the project. It was really tough going and a really steep learning curve but I finally see the light at the end of the tunnel. So now over a year later and having taken longer than estimated and costing a small fortune; my eighth head casting, so far seems to be usable and I just have a small amount of finish machining to do.

The latest progress is I have the engine mounted on a test stand/dyno that is a work in progress (I'm also building a water brake from scratch). I'm getting the engine wired up and plumbed at the moment. I have a few more parts to make and it will be go time.

14666228_1282859418423136_4878102524189959049_n.jpg


14991056_1296557897053288_5795456410961411209_o.jpg


More pics here: https://www.facebook.com/pg/goldenfabllc/photos/?tab=album&album_id=1128121320563614

Regards,

-Adam
 
All i can say is wow! youbhave done great with this project,

Can you explain the reasons for this and whats so different in terms of our normal head and cams etc vs this? any power differences or does it change whats inside to move valves etc.

I have never seen this before and its cool looking. so more info needed haha.

Keep up the great work and welcome to the forum
 
Incredible story and work here. I'd love to see how the final product performs, just by itself not to mention compared to a 4g63 overhead valve! Keep us updated on your progress and if you are able to bring anything to market. Before going any further, definitely get your patent work sorted...
 
Thanks Bobby, To answer your question rotary valve head designs are nothing new and there are many design flavors. There are numerous patents on them and a few designs that have been in production. The design I made is very similar to a ball valve (think of a ball with a hole in it that rotates past a port).

The Good:
-No valve float so unlimited valve train RPM
-Non-interference design of the pistons/valves
-More flow
-Cooler exhaust valve which decreases detonation which allows for a higher compression ratio

The Bad:
-As far as I can tell nobody has had great success getting them to seal properly and they wear out way sooner that conventional poppet valves
-The assumed benefits above could be a total myth

I am happy to talk about the design and entertain constructive comments but keep in mind rotary valves vs poppet valves have been discussed plenty and why one is better than the other or why they will never work etc. Bobby, this is at no way directed at you or your comment, just a preemptive attempt at keeping this thread on topic - building a rotary valve head and discussing it (suggestions welcomed) vs discussing why it will/won't work.
 
Very cool! I'm super interested.
If they wear out at a higher rate, is the cost associated with replacing the valves quite expensive?
I'd think for the hard core racers, replacing those rotary valves every season wouldn't be that big of a deal.

When do you plan on testing!?
 
I'm excited there is interest in this project.

Crash, I'll let you guys know how it goes for sure.

Sp1kE, the plan is that the valves would not wear out very fast but the seals would be the wear item as they are small and inexpensive to replace. Going to be doing some R&D on some material ideas I have up my sleeve.

I'm working on a modified cam position sensor at the moment since this head does not have any cams. I still have a lot of other little things to hook up and time the valves. Could be a few days if things go exceptionally well or a few weeks more likely.
 
Thanks Bobby, To answer your question rotary valve head designs are nothing new and there are many design flavors. There are numerous patents on them and a few designs that have been in production. The design I made is very similar to a ball valve (think of a ball with a hole in it that rotates past a port).

The Good:
-No valve float so unlimited valve train RPM
-Non-interference design of the pistons/valves
-More flow
-Cooler exhaust valve which decreases detonation which allows for a higher compression ratio

The Bad:
-As far as I can tell nobody has had great success getting them to seal properly and they wear out way sooner that conventional poppet valves
-The assumed benefits above could be a total myth

I am happy to talk about the design and entertain constructive comments but keep in mind rotary valves vs poppet valves have been discussed plenty and why one is better than the other or why they will never work etc. Bobby, this is at no way directed at you or your comment, just a preemptive attempt at keeping this thread on topic - building a rotary valve head and discussing it (suggestions welcomed) vs discussing why it will/won't work.
Its ok i cannot critisize as i know nothing about it and i dont plan on taking the thread anywere but finding it out through the thread via yourself,

All in all its great at what you have done and the progress you have gotten, its also great you chose to use a 4G platform aswell
 
Coates has been designing these heads for some time now. It's pretty cool to see something like this being made for the 4G63.

I can't believe you're basically doing this in your garage. Absolutely incredible. Good or bad, I can't wait to see more testing!
 
Has anyone seen anything actually for sale from Coates or anything they make independently tested? I called them years ago and told them I wanted to test out something they had, anything, I said name the motor and I'll buy it and they had nothing for me except to sell patent rights nobody could afford.
 
Well i knew someday, someone with more time, money and skill would do this :D.

I had this idea about 6 years ago after seeing Coates design, thought it'd be a fantastic setup if a few design questions could be answered. I never could figure out a clever sealing practice, or at least test one. congrats on your prototype! if it works then I could see massive rpms and flow capabilities, as well as non-interference plusses! :applause:

I'll post back later with some specific questions and whatnot for discussion purposes.
 
Holy macrel, this is probably the most dedication to an idea I've ever seen. You should probably watch that movie about the intermittent wiper guy so you don't get screwed over by any big corporations
 
This is awesome. I can totally identify with the back story as well. I'm in my last semester of a mechanical engineering degree and doing CNC work at the student shop. I can't imagine trying to take this on now even on a lawnmower engine. Great perseverance man and I can't wait to see the results.

I'm sure you don't want to divulge too much about your design but would you mind describing your deal arrangement? All the ball valve packings I have seen would not hold up to the high speeds or temperatures involved with this application.
 
This is awesome and I am glad somebody is taking it from conceptual to a working prototype.

I am curious as COATES design (based on its animations) seems to have absolutely no overlap between the intake chamber and the combustion chamber during the induction cycle (down stroke), it just fills the cavity with whatever air mixture enters the valve cavity when the opening reaches the intake chamber. This means this air is not being sucked directly from the intake manifold by the downstroke of the piston. Does yours have any overlap?

Usually on poppet valve design a turbo would push all the air possible directly into the combustion chamber when the piston is in the downstroke and even slightly on the up stroke while closing the valve continuing to push as much pressure into the same volume as it can. In this design there is a disconnect of the amount of air the turbo would be pushing into the system since it is limited to only the air that will be pushed into the valve hollow cavity. Is that cavity larger than the combustion cavity? Would this disconnect cause pressure loss or seepage through the piston rings? Will the downward stroke be able to absorb the full amout of air from the cavity? The pressure will help but since it won't be forced by additional air, will it just fill both cavities and leave some of the air off the table?

I'm very curious of how the design would affect a turbo application as ours.
 
AdR, great observations. As far as timing goes I have not got there yet. My initial design has the valves open/close exactly at TDC/BDC without any overlap for the proof of concept prototype to be changed later. The valve ports are in as cast condition so the tolorance are not great and I have yet to measure what the timing is at now that its built... When/if I can get the engine to run reliably I hope to do extensive dyno tuning on the valve timing. I still need to finish the water brake I'm building....

I expect you are right and optimal timing would be close to that of a traditional poppet valve setup. That being said there could be some physics going on with a rotary valve that I have yet to discover that would require different timing.

I lost what you are saying midway thru your third paragraph. Some of the Coates designs have a shared intake/exhaust valve. My design has completely separated intake/exhaust valves and porting like a conventional head. So in theory from a turbocharging perspective I don't think it will be too much different than a conventional head.. If there is something I'm missing come back at me?

I still need to get this head on a flow bench and see what she does... Anybody know of someone that has one in the Prescott, AZ area?
 
speechless here. I remember some 15-20 years ago reading about the v8 version in a popular mag. very impressive power gains as I remember. but nothing come of it. hope you get this worked out and it ends up being worth the time.
 
I lost what you are saying midway thru your third paragraph. Some of the Coates designs have a shared intake/exhaust valve. My design has completely separated intake/exhaust valves and porting like a conventional head. So in theory from a turbocharging perspective I don't think it will be too much different than a conventional head.. If there is something I'm missing come back at me?

My train of though during the third paragraph and I apologize since it does sound like a ramble instead of a well constructed thought is:

During a forced induction setup the way a turbo forces air into the combustion chamber is by continuously pushing lots of air into that CC (Combustion Chamber) creating pressure buildup or what we call boost. When the valve closes it shuts the window of the boost buildup right in the initial upward stroke much like when you close a balloon after filling it, then the combustion chamber compresses it even further. In the rotary valve design there is a difference in this scenario. What gets filled is not the CC, but rather the rotary valve chamber. Pressure usually wants to find the path of least resistance and as such as soon as the RV (Rotary Valve) reaches the CC it will start to fill the cavity trying to equalize the pressure differential. As soon as the RV opening and CC reach their maximum spatial volume (valve open to CC and piston in BTDC) the equalized pressure between both will decrease. Since there is no overlap to the boost reference intake chamber, my concern is that the boost you put into the system will not equal the boost being fed by the intake since we reference a turbo boost pressure by a line coming out of the intake to the wastegate for boost control. So a RV engine that references 10psi of boost and controls to that will actually be seeing less boost in the CC. If the RV volume and the CC volume are the same, then the pressure would be divided by half.

Ex. Intake references 10psi -> It forces 10psi of pressure into the RV chamber volume... -> RV closes to the intake -> RV opens to the CC -> CC sucks air in up to BTDC -> Pressure equalizes between RV & CC -> CC only receives 5 psi if = in vol to the RV cavity.

PS. There's always pressure losses in the system, so my example is an exageration assuming no loss in the normal poppet valve which isn't true, but it gets the drift on how the additional chamber further aggravates pressure loss vs a traditional style. But since you're going to be able to test it, it might be benefitial to understand the ratio of pressure lost, how to mitigate it and if overlapping the chamber opening might alleviate the issue.

Thanks and sorry for the lengthy reply.
Cheers!
 
What gets filled is not the CC, but rather the rotary valve chamber. Pressure usually wants to find the path of least resistance and as such as soon as the RV (Rotary Valve) reaches the CC it will start to fill the cavity trying to equalize the pressure differential. As soon as the RV opening and CC reach their maximum spatial volume (valve open to CC and piston in BTDC) the equalized pressure between both will decrease. Since there is no overlap to the boost reference intake chamber, my concern is that the boost you put into the system will not equal the boost being fed by the intake since we reference a turbo boost pressure by a line coming out of the intake to the wastegate for boost control. So a RV engine that references 10psi of boost and controls to that will actually be seeing less boost in the CC. If the RV volume and the CC volume are the same, then the pressure would be divided by half.

AdR, I see what you are saying. This may be true for some rotary valve designs but not for the design I have done. For my design there is 100% overlap of the passage to the rotary valve chamber and the combustion chamber port. Also what you are referring to the rotary valve chamber is about the same volume as the stock porting.

Here is a pic showing the valves and porting thru the rotary valves. The head is oriented upside down with the combustion chamber of cylinder one about center screen, the cam belt gears, fuel injectors, and spark plug should give reference to what is what. I have both valves half open to try to aid in visualizing the geometry. The intake and exhaust ports are highlighted in blue.

15123301_1300597899982621_1930924837117479338_o.jpg




This is some CFD results I played around with. Its really nothing more than a cool looking picture. I would need to do a lot more work and study to get anything meaningful out of CFD.

13240653_1128142150561531_712750646056719823_n.jpg
 
I kinda wish this was invented 10 years ago so the refinement process would be complete by now and the unit available for sale. Very nice work and I am eager to hear the results! Also suprised no automotive manufacturers have implemented this much simpler design yet.
 
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