4-Rotor Engine Question
 

Hey guys.
I'm trying to figure out where they put the stationary gears in this custom made 4-rotor rotary engine. This one uses 12A housings, is there a reason why they didn't use 13B housings?

http://www.autotechmotorsports.com/i...sevenstock.JPG

Thanks!

Obvious reasons are 12a parts are lighter and make the engine shorter for better fitment and weight distribution. Personally I would love to build a 4 rotor with 13b housings and those RB aluminum side plates. It would really be interesting to see how much that engine would weigh.

Hmmm, you would think that larger displacement would be more desireable then less weight... after all, with more displacement you can make more power to compensate for the minimal weight gain from using the 13B parts. Or are the 12A parts significantly lighter?

Any answers about the stationary gears yet?

Thanks!

Does anyone know about the stationary gears? This has been bothering me ever since I thought of it, I still can't figure it out.

Scroll down the page. Stationary gears can be machined to fit in the standard sized center housings and then custom e-shafts are made.

http://www.hitman.hm/engine.htm

Ahh so that's how they did it. The stock center plates have a round opening. I wonder how they keep the gear from rotating when inserted. Also it's odvious that the 4 rotor above has custom made extremely long tension bolts. I don't think they would fasten the block together like the way a 20b is with front and rear bolts since the center plate is so thin. They must have a ton of dowel pins to keep the block from twisting.

https://www.rx7club.com/attachment.p...hmentid=150670

RG you mean to tell me that you haven't tried to do one of these side plate mods yourself? ;)

The duct tape eccentric shaft coupling didn't work so well and the dremel couldn't make a perfect circle in steel!

Thanks guys! That helps a lot!

Now I'm wondering something else, and this is a "noob" rotary question. Do the counterweights on the front and rear of the eccentric shaft cancel out the imbalance of the eccentric lobes on the shaft or the imblance of the rotors?

The rotors. Example S4 NA rotors are heavier than S5 NA rotors. If you swap the rotors between engines, you will also have to swap both counter weights because the S4 rotors are heavier than the S5 ones. I believe all 13b e-shafts weight the same.

Ok thank you!

Another queston... the 787B 26B has four equally sized eccentric lobes, spaced equally apart. Does this mean that the bare eccentric shaft is in balance? The firing order of the 787B Lemans 26B was 1-3-2-4 (If I recall correctly), which means that the #2 and #3 eccentric lobes are phased 90deg apart. Would this cause in imbalance in the centre of the eccentric shaft that would put extreme loads on the centre shaft support bearing? Is this a reason why this firing order is used instead of others?

Thanks!

The lobes on the 26B are 90 degrees apart (which squares everything). The lobes on the 20b are 120 degrees apart (like a triangle). The phasing naturally balances the rotating assembly. I think it also helps with the power stroke as well. I'm sure a real expert on this stuff will chime in on this one. ;)