JaGo

Hello All,
Not that I want to get thrown out after my first post. Just thought I'd give it a spin and see the response.
Take a 13B block. Add an extra housing and rotor to each side on a custom e-shaft. Port the intakes and restrict the exhausts (slightly) to extend the combustion time. Larger injectors, modified exhaust and intake manifolds.
A 26B 2-rotor would have 4 spark plugs per combustion chamber. 2 exhaust ports per side, far less internal friction than a 4-rotor, much shorter block length, and an easier build with a one piece e-shaft.
Has anyone tried or seen something like this? Give me some screams.
Thanks

trainwreck517

iTrader: (1)

yes, but for the custom e-shaft.. it well over 50k.. look at the aussie forums.. search there and yuo will see plenty on this topic.

www.ausrotary.com

JaGo

Actually, a machine shop GM that I know said the existing E-shaft could be cut and lengthened with locking spacers. Less than 500 bucks for the deal. I'm more worried about keeping the rotors locked together.

Prôdigy2nd

iTrader: (3)

i think it would be one hell of a ride but very interesting idea indeed, something that is possibly is a great idea or a great failure, i like the odds i'de say build it before any conclusions are made :P


and one got a few spare 13b's around?


Prôdigy

JaGo

I do. Traded a poor dude who's car burned up in a shop in the middle of building it up. Had this perfect 13B sitting there on a stand and no more car. He didn't have any insurance on the car and the shop only covered the blue book value of the car. All the work and time was gone. He was strapped for cash and owed me too.
I'll be working on this and if I decide to make it go I'll post pics and vids.
I was hoping to get some feedback about people trying to increase the displacement of a rotary engine. Pro's and con's. Anybody have a calculator to figure what the output could be? I'll need to go with BIG injectors and one hella fuel pump to feed that pig.

JaGo

Talked in detail today with a Machine Shop manager about my ideas for a 26B 2 rotor. He is very interested in the prospect and felt it would be easier to mill out a whole new e-shaft with lengthened lobes for the double rotors. Custom intake and exhaust manifolds will need to be designed and fabricated too. Larger coils for the extra plugs and higher flowing injectors to keep the AF mix right. Anybody interested in figuring what is going to happen to the turbos? I'm thinking of switching over to a supercharger if the block comes to that point.
The manager said it would make sense to mill several shafts once the tooling was set up. I could sell the shafts if there was a demand for them. Any takers?

Crit

iTrader: (6)

I thought about this earlier, as well. My thought was to use a newer 13B center iron and housings, then 12A housings and endplates. that way you don't have any problem with the coolant seals because housings are mated to their native endplate or to a housing that works out right. Besides, as long as you'd go novel, why not mix 12A and 13B hardware.

It also saves you nearly an inch on the build length and has it very close to a 20B length.

now

iTrader: (1)

cooling the inside of the outside rotors might be a problem as the oil jet wouldnt reach that
far and putting another jet on the other side is hard to do because there isnt room for it
same problem with a home made 1 rotor motor based on the 13b, no place for the oil jet
matt

JaGo

A custom e-shaft with the same oil ports in place and a slight increase in oil pressure should keep things lubed enough. I've got a good 13B on an engine stand and access to a shop manager looking for some moonlight work. Pretty good combination.
I was just thinking about keeping this thing balanced.?.?

now

iTrader: (1)

custom e shaft or not there is no place to custom put a oil jet for the outer side the
main bearing is in the way.

JaGo

If the rotor journal is twice as long, why would there not be enough room for a second oil port. Each rotor could have an oil port and run smooth and cool. When the shaft gets milled they will drill all the standard ports and then two more.

JaGo

I have a standard e-shaft being blueprinted and put into a CAD file. I'll be giving the file to the shop manager soon and then we'll see what the starting cost of this little "project" really is. I'll need to widen the intake and exhaust to compensate for the extra rotors. Anybody want to venture a guess as to what will happen when the 4 exhaust ports start breathing into the turbo? I'd love to get some ideas.
Thanks

MrDirt

Custom E-shafts are not that pricy. About $3,500. You will also need a center housing that has stationary gears on either side. There are plenty of other things too, like getting PP housings made and stuff (no one in his right mind would try to do a side-port 4 rotor). If you did all of the rebuilding yourself, as well as a decent amount of the fabrication for easier things like an oil pan, I think you could make a respectable engine come together for around $15k. That still wouldnt solve things like what EMS to use, and just mounting the damn thing...

MrDirt

oh, my bad... I didnt understand exactly what you were saying at first... that price of 3,500 was for an actual 4 rotor e-shaft...

rotariesrule

what about the apex seals and springs? the e-shaft will probably flex with all that weight towards the center. oil will probably drip out between the rotors. one good thing is the torque increases with the width of the rotor not the length. four spark plugs per rotor would mean more chance of detonation. can you upload that cad file?

MrDirt

I would have to suggest reading the other four rotor thread that has been active recently... you would probably have the same power/torque if you coupled two motors and ran them at zero offset.

Xeros

that woudl be some very intresting fabrication and ems tuning.

Herblenny

iTrader: (13)

I'm wondering how you are going to put 4 spark plugs per single combustion chamber??
how are you also going to tune this thing?? The thing is that 3 or 4 rotor might sound great in theory, but its useless when you can't get the damn thing to run.

13btnos

iTrader: (1)

After reading through this thread please correct me if I'm wrong you want to butt up to rotor housings up against each other and make a custom e-shaft with wider lobes to accomadate 2 rotors butted up against each other. I hope I got that correct. But anyways my question would be how do you seal the rotor housings and second what do you do about the rotors? Even on a custom e-shaft I still can see a lot of flex ocurring with the weight of 2 rotors on the same lobe. Interesting idea if I interpretted it correctly.

Herblenny

iTrader: (13)

Now I understand what you are thinking about doing.. Ouch! I don't know.. Putting two rotors together to make 26B?? I wouldn't even try..

Funkspectrum

iTrader: (5)

whoo....

I'm sorry but that's a little on the crazy side....
I'd just build a 4 rotor and be done with it.....

JaGo

I have thought about just going the "standard" 4-rotor way. The 2-rotor 26B would have some very good benefits. Double the engine displacement and only increase the block length by 1/3. Less internal drag/heat than a 4-rotor. Much easier build than a 4-rotor. 4 plugs per chamber.
Mounting modified stationary gears to the center plate is straightforward. Keeping everything together is also basic. Doubling the ignition output seems doable too.
My biggest question is if someone has already tried this and I'm wasting money making a bomb that is going to take off my shop and/or head.
Most of the flex in the shaft happens between the rotors in the tapered area that spins in the center plate. A single peice bearing/dual stationary gear that would lock into a milled out center would cut the flex, stablize the increased mass of the rotors, and aid in engine buildup. It would completely seperate the two sides and make things a lot cleaner.
I'm going to use a dummy plate on the bottom end to mount the standard oil pan to. The original intake and exhaust can be frankensteined to mate to the new locations. I'll use an extra exhaust manifold to make it a 4 to 2 setup that goes into the tubo.
I happen to work at a major university that has no shortage of engineers. Any type you could think of. I am utilizing this resource to the fullest.
I want to get feedback from this forum because you are the real world. You own and drive and work on these machines. An engineer can tell me something looks good according to a modeled result on a computer, but he has never had greasy hands and busted knuckles.

theman4444

Seriously, I don't believe the housings could hold the pressure of both rotors pinned together. If this wasn't true then why didn't mazda just make the stock 13b with one large and LONG rotor in a 13b to save space, putting aside the fact that it would be kinda off balance. The stock housings just wouldn't hold that kind of force without leaks or a nice boom. I'm thinking you'd have to custom fab an entirely new, one piece, THICK housing for each dual rotor. Thick meaning the outside daimeter.

autopaul

plus youd need some crazy dowel pins, and longer bolts. i think it would be crazy unbalanced. and have low compression do to pressure being lost everywhere, but still a novel idea. !! id say be the first,

Eson

A smaller engine with more pistons/rotors revs faster and higher then a big single piston/rotor, thats what you want in a sportscar like the RX-7. A big single engine got a lot more torque.