Mazda Rotary Wankel Swap Willys

Awesome project thinking outside the box!  Looking forward to watching your progress!

-Barry

And that Jeep is a real looker regardless.

Best of luck .

It only weighs on at 2250 lbs 

After watching your videos about how you can fit the 5 speed in there with the 13B, I think you made the right choice with a 2 rotor. That never crossed my mind. I think this is going to be one of the most versatile flat fender swaps ever done. Do you have any plans for bumping up horsepower, or just keeping a reliable NA engine?

The torque curve is very flat and the power comes on strong but rather gently with a rotary.  This means, for trail work, keep the revs up and downshift early.  Keep your foot in the throttle and the rig will pull nicely without jerking the driveline or the Jeep around with torque peaks and valleys.  I think it will work fine.  You have 7k or a bit more for a rev limit, so you can scream it up the inclines when necessary.

There is the matter of heat with these things.  Imagine jamming a V12 through a single two-outlet into one pipe exhaust manifold, with constant high revs.  That’s the equivalent here.  You need to get heat out of the engine, and not burn anything up among the rig and passengers along the way.

Take a look at the radiator in the RX.  It is tall and wide (and mounts at an angle to get extra height), but it is not thick like an old CJ radiator.  It is actually thin in depth, which aids heat transfer.  The old CJ radiator is more of a heat sink than a heat transfer (to the air) device, because it doesn’t need to be.  For the rotary, you need to get the heat out of the radiator through efficient transfer.  Make the radiator as tall and wide as you can, given the space.  Nd put a fine mesh screen in front of it.  A rock hole in the radiator will fry the rotary instantaneously, like nobody’s business.  Also an external engine oil cooler, a big one (again big but thin) is the best.  The tranny is fine without a cooler.

Now, the exhaust pipe.  It will get very hot.  Use thick wall tubing. Mount it away from the fuel tank (not hard to do, tank is on driver’s side and the exhaust exits to the right).  Also, mount it with an air gap to the floor.  Here’s where scavenging from the RX is useful.  Take the exhaust pipe shields and adapt them to the Jeep. A set for between the pipe and the floor of the rig, and a set to isolate the pipe from the ground.  Leave the sides (the verticals) open for heat dissipation.  But you don’t want to start grass fires with the exhaust pipe.  Like a hot cat converter, the hot exhaust will light stuff up.  It sometimes glows orange at the head end, that’s how hot it can get.

You can use glass packs, that’s what I use for roto project vehicles, but get steel wool packs for the muffler at the head end, to keep from burning out the packs.  Racing Beat has a pricey but good piece available.  Chambered mufflers don’t work well on rotos, very loud and the sound quality is piercing.  You don’t want to beat up the ears of your trail mates.  Glass packs give a nice sound, and three of them will get it somewhat quiet.  The RB piece followed by two Cherry Bombs works well for me.

Feel free to reach out with any questions.  Will follow this one with interest.