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-   -   A 4-Rotor discussion. (https://www.rx7club.com/rotary-car-performance-77/4-rotor-discussion-464477/)

Bob's #45 09-19-05 02:24 PM


Originally Posted by 13btnos
http://www.kiwi-re.com/index.php You might want to get in contact with this person, Alec Bell, he makes custom 3 & 4 rotor engines. He has custom eccentric shafts and uses the center intermediates to make the engines shorter and help in controlling flex. Engines are PPort motors look around his site and you will see pictures of the 3 rotor engine I didn't find any for a four rotor but there is a guy with one name is Bryce McEwan he has a 4 rotor FD. Car is from New Zealand.


Thanks.. I saw a vidio of that car , It's pretty much what sold me on a 4 rotor

Bob's #45 09-19-05 02:25 PM


Originally Posted by Low Impedance



Whats your idea on it ?

Whizbang 09-19-05 02:28 PM

looks like they modied the intermediate plates to run the coolant to the top of the plate for the in and out. It said they blocked off thefront cover componets shortened down the assembly. which makes sense. that area needs to be as simple as possible,

Bob's #45 09-19-05 02:29 PM

Do you think it would help keep the rear rotor cooler?

Bob's #45 09-19-05 02:32 PM


Originally Posted by Low Impedance
only thing is i might have to make the adapter piece in two parts. becuase in order to get the chain connected and clamped, i would have to get the rear section on while trying to get them to line up, so if i left a bottom accessto get to some of the bottom of the pulley i could clamp the connection. then attach the bottom piece.



It would be a tight space.

Whizbang 09-19-05 02:37 PM

its more direct so i would presume so. you would almost have to inorder for it to cool anything. run the lines so that the rear gets coolant which is not fresh from the hot front section is smart. seeing by the time it affected the rear, little if any cooling would take place.

What also interests me is that by running it "stacked" so that the Fr1 and RR1 fires at the same time but 180 degrees offset meant the need for two counterweights is eliminated. that might be the smarter way to go. Seeing that space and simplicity will become a important factor. Also, with the cooling, you could then have the adapter plate be much more rigid if there are no cooling ducts. its obviously carbed with the crappy points igniton and it still made 550ish Hp. meaning that using more state of the art methods for the igniton, i would be easy enough to break that barrier. FI is best.

so lets say that Method 2 is altered. so the shafts are 180 out of phase AND fire together to act as natural counterbalances.

Bob's #45 09-19-05 02:43 PM

Seems to me that the counterweight is used to offset the weight of the rotor some, witch in turn would put less stress on the main bearing. So to me I think it would be a good idea to keep it.

Whizbang 09-19-05 02:45 PM

there is a page now about making the coupler. there is a link at the bottom of the page. its interesting. but it seems like the draw bolt wont not allow for the oil jets to function

Whizbang 09-19-05 02:48 PM


Originally Posted by Bob's #45
Seems to me that the counterweight is used to offset the weight of the rotor some, witch in turn would put less stress on the main bearing. So to me I think it would be a good idea to keep it.


you retain outside counters but the inside counter would require no counterweights seeing that the rotors themselves act as counterweights.

Bob's #45 09-19-05 02:50 PM


Originally Posted by Low Impedance
there is a page now about making the coupler. there is a link at the bottom of the page. its interesting. but it seems like the draw bolt wont not allow for the oil jets to function



Yea I saw that, they drilled the center of the shaft 10mm so oil could pass.

Lynn e. Hanover said " If you make the junction ridged, you would go nuts trying to keep the rear crank in it".

Jeff20B 09-19-05 02:52 PM

I'd like to do a 4 rotor engine some day. I'd prefer one rotor face every 90° so it will sound like a 4 rotor engine. The problem with two rotor faces every 180° is that it would sound like two 13Bs reving up together instead of the awesome 4 rotor sound.

Whizbang 09-19-05 02:52 PM

i have to get to class.

Bob's #45 09-19-05 02:52 PM


Originally Posted by Low Impedance
you retain outside counters but the inside counter would require no counterweights seeing that the rotors themselves act as counterweights.



They would but only if you used a sollid type coupler like granny's did.

Bob's #45 09-19-05 02:54 PM


Originally Posted by Jeff20B
I'd like to do a 4 rotor engine some day. I'd prefer one rotor face every 90° so it will sound like a 4 rotor engine. The problem with two rotor faces every 180° is that it would sound like two 13Bs reving up together instead of the awesome 4 rotor sound.


Nothing sounds better.

Michael_Rudy 09-19-05 05:52 PM

I am actually 50 % done on a 4 rotor 12a build up, the coupler we are getting machined right now is a 35 spline unit, and then we had the eccentric shafts built up and 35 splined, its actually the same spline as a ford 9 inch rear end 35 spline axle. The couple actualy bolts onto the back engine so you can adjust the end play of each engine seperatly before putting them togethere. we are running the engines in sync for hopes of some good torque multiplication. we are also using an external oil pump and electric water pump, our center connecting plate is 3/4 aluminium. We are only going to run a bridge port but the engine is going to be twin turbo'd at 18 psi, we are hoping to make between 800-900 rwhp on pump gas, which should be possible, and should make the rx3 its going into a fun street/strip car. we hope to have it finished by summer of 2006.

We looked at doing it the way with the chain and gear like a fellow has done before in that tractor puller, but the engine would have to be a great deal longer, and the system of doing it seemed very mickey mouse.

Bob's #45 09-19-05 06:44 PM


Originally Posted by Michael_Rudy
I am actually 50 % done on a 4 rotor 12a build up, the coupler we are getting machined right now is a 35 spline unit, and then we had the eccentric shafts built up and 35 splined, its actually the same spline as a ford 9 inch rear end 35 spline axle. The couple actualy bolts onto the back engine so you can adjust the end play of each engine seperatly before putting them togethere. we are running the engines in sync for hopes of some good torque multiplication. we are also using an external oil pump and electric water pump, our center connecting plate is 3/4 aluminium. We are only going to run a bridge port but the engine is going to be twin turbo'd at 18 psi, we are hoping to make between 800-900 rwhp on pump gas, which should be possible, and should make the rx3 its going into a fun street/strip car. we hope to have it finished by summer of 2006.

We looked at doing it the way with the chain and gear like a fellow has done before in that tractor puller, but the engine would have to be a great deal longer, and the system of doing it seemed very mickey mouse.



Thanks for the info, the coupler sounds like a genius design. How does it work? do you use some sort of bearing? Iv'e been wondering about end play becouse it's so important. With this setup are you using the counterbalancer?


Thanks again for the info.


Bob

Michael_Rudy 09-19-05 07:16 PM

i have a very detailed drawing of it i will try and find a scanner. I only use you front counter weight of the front engine and the rear of the rear engine. i just re-read what i said and may have been a litle missleading we only welded up the rear of the front engines eccentric shaft and cut it down too the 35 spline the front of the rear eccentric shaft is being having a 24 spline of the original diameter, then a bolt is slid through on the large 35 spline and and screws into the front of the rear eccentric shaft you you can still have all the stock bearings in play, you just need to get the front end cut down to accomidate for the lack of the oil pump and counter weight. We are trying to build this as easily and cheaply as possible so we will be able to sell kits

Bob's #45 09-19-05 07:28 PM

So you are using a draw bolt all the way through the front shaft?

Whizbang 09-19-05 07:38 PM

im having a hard time understanding this 35 spline to 24 spline coupling method.

Bob's #45 09-19-05 07:44 PM

That is a really cool idea. Are you feeding oil to both engines through the front housings? & what about cooling routs?

Bob's #45 09-19-05 08:30 PM

Hey low impedence, if granny's made 550hp w/carbs , your Pport should be awesome even n/a . Are you thinking about running any boost?

Whizbang 09-19-05 08:39 PM

more than likely im going to run this NA until ive worked out my quarks. Make some nice tubular headers. Then more tuning than i care to think about. Looking into individual throttle bodies too.

Bob's #45 09-19-05 08:56 PM

And your going to put it a 2nd gen, I mesured mine it's going to be a tight fit. I cut out all the radiator mounts & will have to move the trans location back 8'' to 10''.

Whizbang 09-19-05 08:59 PM

yeah i think im going 8 inches back into the firewall and the rest upfront

Bob's #45 09-19-05 09:06 PM

Alot of work but worth it.


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