Build a Rotary Miata in 4 Days?

We’re headed to North Carolina tomorrow morning. Why? To build a car, of course. Mike Smith, better known as “Curmudgeon” on our online forum, passed away unexpectedly after battling cancer.

And he left behind a radical, unfinished project: A turbocharged, rotary-powered Mazda Miata, originally intended to take on hillclimbs. He also left behind an only daughter, Carly, who plans attend …

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Great cause. I'm in. Let me get home first and see what I can do.

I will be there at the garage probably in the afternoon. Going to get off work early and drive up from Charleston

Will the car be auctioned or will you sell raffle tickets? Because if it's tickets, count me in for a lot.

I should be up there either Friday and/or Saturday.

Javelin wrote: Will the car be auctioned or will you sell raffle tickets? Because if it's tickets, count me in for a lot.

Good idea! Also in for raffle tickets.

You're doing a great thing here.

Robbie wrote:

Javelin wrote: Will the car be auctioned or will you sell raffle tickets? Because if it's tickets, count me in for a lot.

Good idea! Also in for raffle tickets.

This. I can't afford to bid on a car, but i could go for a raffle ticket or twelve.

I too like the raffle idea.

I can do raffle as well, but cannot bid. It depends on if you believe 1,000 tickets at $20 each is better money than what the car will bring at auction.

In reply to Fueled by Caffeine:

Hey Tom, Fueled by Caffeine just offered to by 1k tickets at $20 a pop!

Raffle tickets? Id buy those. Also, lemme know if the car comes to grm hq. Ill drive up to lend a hand.

Where in North Carolina and what days? I'm good with electrical stuff. My buddies call me sparky.

We're just a few minutes away from Curmudgeon's garage. Updates coming soon!

Are you guys starting with a plan or developing one when you get in front of all the parts? It will be interesting to see how you tackle some of the standard rotary miata swap issues.

At this point, we're mostly making things up as we go along. We're limited by time, tools, space, and parts, so we're going to see what we can make happen with what we have.

Now, onto the photos!

Alright so things are progressing.

Engine just about to be removed.

Too many cooks make light work.

Engine out after a fair amount of prodding.

Obviously a last-minute addition at one point. The mount for the fire extinguisher is held on with a rivet, a torx bolt and two flat-head screws.

Getting ready to swap everything over.

Ya'll are Special folks.

You have some experienced fabricators among you so I have to ask instead of just blurting it out, so-do you guys want suggestions, or would you rather figure it out as you go?

In reply to MrJoshua:

Blurt it out!

All of this is from working with Miatas a bunch and reading rotary swap threads but never actually doing it so

-It is really hard to use the PPF. Trying to use the Power Plant Frame with some combination of Miata transmission tailshaft on an RX7 transmission pushes the engine too far forward requiring pretty heavy hacking of the stock subframe and lots of oil pan surgery. IIRC you then still end up with the front of the engine sitting really high or having to relocate the steering rack. The PPF also tries to occupy the same side of the transmission tunnel as the exhaust creating its own set of problems. If you dont use the PPF a transmission mount like an old school V8 mount (rail to rail) would be simple and work well with a stock RX7 style transmission mount. A single post style motor mount mounted on the front rail of the rear subframe with a short front diff mount extension will mount the front of the diff and compliment the stock wing mounts.

-You can move that shifter turret on the transmission by only using the front mounting holes and shortening the rod that goes into the transmission. It looks like Jensenman already moved it forward about 4". It looks like that garage has multiple rotary transmissions around so some combination of transmission/tailshaft could put the shifter anywhere from several inches behind the end of the transmission to about 6" ahead.

-The "ears" sticking into the engine bay where the transmission tunnel meets the firewall can be cut off to give you some more rearward room in the engine bay.

• I would seriously consider venting the hood, at least above the turbo. I would then consider a simple deflector style heat shield between the intake manifold and turbo.

I know Tim has done the rotary swap thing before and some of this is basic stuff but hopefully some of it will be helpful. I look forward to seeing how you guys conquer some of the common issues. This project is a wonderful tribute to the man Mike was.

So, if the car gets raffled off, for $20 a ticket, is the value $20 if the winner wants to enter it in the challenge?

MrJoshua wrote: All of this is from working with Miatas a bunch and reading rotary swap threads but never actually doing it so -It is really hard to use the PPF. Trying to use the Power Plant Frame with some combination of Miata transmission tailshaft on an RX7 transmission pushes the engine too far forward requiring pretty heavy hacking of the stock subframe and lots of oil pan surgery. IIRC you then still end up with the front of the engine sitting really high or having to relocate the steering rack. The PPF also tries to occupy the same side of the transmission tunnel as the exhaust creating its own set of problems. If you dont use the PPF a transmission mount like an old school V8 mount (rail to rail) would be simple and work well with a stock RX7 style transmission mount. A single post style motor mount mounted on the front rail of the rear subframe with a short front diff mount extension will mount the front of the diff and compliment the stock wing mounts. -You can move that shifter turret on the transmission by only using the front mounting holes and shortening the rod that goes into the transmission. It looks like Jensenman already moved it forward about 4". It looks like that garage has multiple rotary transmissions around so some combination of transmission/tailshaft could put the shifter anywhere from several inches behind the end of the transmission to about 6" ahead. -The "ears" sticking into the engine bay where the transmission tunnel meets the firewall can be cut off to give you some more rearward room in the engine bay. - I would seriously consider venting the hood, at least above the turbo. I would then consider a simple deflector style heat shield between the intake manifold and turbo. I know Tim has done the rotary swap thing before and some of this is basic stuff but hopefully some of it will be helpful. I look forward to seeing how you guys conquer some of the common issues. This project is a wonderful tribute to the man Mike was.

Thanks for the tips, MrJoshua. Tim isn't actually up here for this, but I think you'll be impressed with our progress either way.

What Curmudgeon left for us:

Installing his mounts:

Looks like we need to trim a little more.

I didn't know Crumudgeon other than this board. But it seems to me that had he finished this build, he's share on this board how it was done. This swap has seemed obvious since 1989, but has not been a very common one, especially compared to V8 ones. As I understand it, as Joshua put it with details, the fabrication can be a PITA.

So I hope you guys plan on sharing the details of the swap on this board.

(not for me, I'm not a rotary guy, and my days of fabricating are regressing behind me- but there are so many talented fabricators on this board, AND so many who want to be good fabricators)