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So you want to swap a ROTARY into your Z! (how-to)


auxilary

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I must see more about this. The reason I sold my 240Z was because I wanted to make room for an FD3 RX-7. Now that I have got the rotary bug I have been starting to plan out a build for a 20b 240Z... what was your reasoning for not using the 20b? Expense of the motor (since they are about double the price :()?

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  • 1 month later...

Wow. This build looks intense. My hats off to you Aux. I stumbled on your post and was really amazed at this. I drive a T2 so pre-mix isn't a big deal. Seriously, it becomes a routine when filling up. I'd love to see a video of this car when its up and running. Keep us posted!

 

BTW, what type of rear are you using to keep the power down?

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  • 2 weeks later...

Aux, I'm a rotary novice, so please, don't hurt me... :)

 

The 20B is basically a 13B with an extra rotor and a longer eccentric shaft. If so, is it possible to fit a 20B using the original 13B mounts? I read a few articles with 20B-swapped RX-7s, and they all used custom (or modified) subframes. Another question - is the 20B much longer than 13B, i.e. will it fit behind the shock towers if mounted close to the firewall?

 

It's sucha a pity that there are no rotary specialists in my area... Rotaries are usually swapped out in favor of conventional piston engines, and Wankel powered cars are becoming rare these days. I once drove a carbed 12A RX-7, and I instantly fell in love with the engine. I've been thinking about a rotary in a Z ever since...

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i'm using a front mount points from a 12a/13b from 1st gen rx7. standard 13b/20b mounts are on the sides at the rear of the block.

 

You could theoretically mount a 20b to end at the strut tower level, however, this would shove the shifter about 7-8" further back, and it'd be a paint in the butt to shift. 20b is about 1/3 longer than the 13b. It's an extra rotor housing and extra side housing, about 7-8 inches, or 177-203mm

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you could theoretically use the stock ECU, but the stock ECU for the 13b-re is mapped for automatic transmission only.

 

Advantage of stand alone is you can do away with the rat's nest of vaccuum lines and senders that aren't needed for a swap.

 

Of course, you can use a stock 13b ecu with 13b s4 or s5 motors. Mine's not as much of a common rotary as others, despite sharing a lot of things

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Great to see another rotary swap. If you haven't already found a place for the oil return line, there's two place's you can use. One is the stock location on the rear housing behind the exhaust, you can simply cut out the hard line out of the flange and weld a steel AN fitting on it. The other is the front cover just behind the OMP. If your using the gsl se cover just below the omp is great place for it simply drill a hole and tap in a new thread for a AN fitting. I used the front cover for the oil return line on my Rx3 and I used the rear housing on my friends 510 this car also has a Cosmo RE motor on it.

 

As for the OMP I use the "poors mans" way using the mechanical OMP from the first gen RX7 and leave it open half way it will smoke a little at idle but works great (This is on the RE 510). If you want to get creative go to the RX7club there's ton's of write up on the OMP. And check out Rotary Aviation the sell some kind of gadget. I just premix it not that bad.

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yep, already did that.

 

I'm just going with running pre-mix

 

Ahh some how I missed that. That motor should give you at least 350 - 400 whp. look's like you've done your home work the swap looks great.

 

The 3 rotor may fit in there nicely, the T2 trany can can be shorten by 4" from the shifter housing which bring the shifter up forward just below the stock shifter hole. But yeah it very expensive to build.

 

 

Note to my self: follow this build....

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