Custom building "26B" engines
 

A friend and I have taken up the HUGE task of taking two NA Miatas and putting 4 rotor engines in them. I mainly am posting this thread bc I have seen people mate two 13b's together to make "26b" engines(I know these aren't real 26b's I know the real ones have variable geometry intakes and other differences). This is a HUGE project so he and I were wondering what we would need to do to mate the 13b's together also how have other cars gone about making a subframe for these engines? I've seen 20b's inside of slightly modified 13b subframes. I am assuming because of the longer engine this wouldn't be viable. In addition, if you used the stock 13b faceplate could you attach the alternator and A/C and power steering pumps to it? I don't care how long this build will take. I would like to do it without ridiculous amounts of money but I understand that it wont exactly be cheap.:lol:

Thanks in advance! I know this sounds noobish but I have a lot of people helping with these cars and I know they will get done some day. I don't care how long it takes and money is not too much of an issue.

I think "Rotary Hoe" uses a couple sprockets and a double row transfer case chain to link two 13Bs together.


This thing has been pullin' it since before I was into rotaries (at least 15 years).

A 4 rotor is a pretty damn long engine, two 13Bs together are a good bit longer. I was thinking on my RX-8 keep the stock engine location and cut the firewall/trans tunnel to put the other rotary behind it and put in a custom tube backbone frame to replace the trans tunnel.

Probably end up driving it from the backseat by the time I get a transmission in there too, which isn't an option for you in the Miata I guess.

well I meant like having then directly attached into one motor. Like use the midplate of a 20b to attach them both together.

Well, there aren't any parts to make the two 13Bs just match up magically into one 26B 4 rotor.

Here is an old site showing how Granny's Speed shop made a 4 rotor from two 2 rotors with some machining.

http://grannys.tripod.com/4rotor.html

I know I'm gonna need the eccentric shaft so I'm willing to machine stuff but what should I do to attach them? If a 13b midplate was in between then would it work with larger bolts to attach them together.

You might check out these guys. They sell complete 4 rotors but it'll cost ya.
DEFINED AUTOWORKS - Service | Repair | Performance for Mazda RX7
Looks like they are using three 13b intermediate housings. They don't list them on their site for sale but give them a call. Maybe they will sell you the E-shaft they are putting in their motors. Sounds like the will have to balance it and your rotors though if they will even sell you one. Here's a video of I think their original build.
Looks like the E-shaft is a multi piece unit.

Thanks I just emailed them about the eccentric shaft.