dollraves Reader
May 23, 2011 3:39 p.m.

Update 4/4/2013: Someone pointed out that this thread is in the top 10 Google results for "rotary miata" (gogo GRM for excellent SEO!). Please note the build thread has moved to http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/2013-rotary-miata/61989/page1/


Dear $500 Miata,

Meet your new friend, the $700 RX-7.

Bought this 1990 RX-7 last weekend from a young man in San Ramon. My understanding is that he and his dad bought it from the original owner with a dead engine, bought a rebuilt engine and swapped it in. Poor kid had it for two weeks and spun it out in the rain, tangled with a barbed wire fence and landed in a ditch. Subframe is shredded, driver's side control arm is ripped out, and there's not a panel on this car that isn't crumpled or scraped up. [Be nice to the young gentleman, boys, I'll be sending him this and subsequent threads so he can see how I use and abuse his previous love!]

I know nothing about rotaries, but, hey! Learning experience, right? (Why are you laughing??) It starts, doesn't leak oil, no burnt oil or coolant smells...I didn't see any pools of fluids beneath the car (it had obviously not moved in months), so for $700, figured I'd take a chance. Here she is after the tow truck managed to get her halfway into my driveway.

Before the tow, I removed the battery since it was just sitting in there loose and unrestrained. The hood went up and down before the tow; now, though, the latch is stuck. So once I get some decent car dollies (darn Harbor Freight for it's cheap but flimsy dollies...the two in the rear bent when I set the car down), I'll get a bunch of friends to help me push it into the garage and start taking it apart.


This build might be a $2011 contender, but more likely $2012. I'm still not fully recovered from my surgery, so there's a limit to what I can do for another few months. I'll come out to $2011 to shag cones, if nothing else. :D

As I drove back from the $2010 Challenge, SVRex and I were chatting on the phone (thanks to so many of you for calling me and keeping me amused during that long drive!! I was using a hands-free set, promise!). I said that the GTXes were done for the Challenge, and he agreed. He told me, "You know, you keep saying how much you regret selling your Miata. You should get another Miata." I pointed out that used Miatas were ridiculously expensive in CA. Paul told me to just keep my eyes open. Not 12 hours later, a friend forwarded me an email from his neighbor. She'd sold her property and needed her dead Miata gone before Nov 1, and did he know anyone who'd want it for $500? I sent SVRex the good news: Miata acquired!

As I pondered it, and Craigslist, over the next few weeks, I noticed early RX-7s can get really cheap around here. I called SVRex again... "Talk me out of a rotary Miata." He laughed and said he couldn't. I asked him if it was within my skill level, and he felt it was. I talked to my local rotary performance guy who used to work on my '95 Miata, Paul Elenga at Rotorsport on El Camino in Santa Clara....two out of two Pauls agree: Carlota should be able to do a Miata rotary swap. :D

That's kind of the nice thing about being a novice. Conceptually speaking, an MIata engine swap is a lot of work... a Miata rotary engine swap is simply more work. Please do not point out that the scale is logarithmic!

So...step 2: RX-7 acquired! Next step...Profit! Er, Rotary Miata!

First, though, I gotta get that hood up. ;)

92CelicaHalfTrac SuperDork
May 23, 2011 3:42 p.m.

Rotary Miata? I approve wholeheartedly.

GET TO IT!!!!

Strike_Zero HalfDork
May 23, 2011 3:44 p.m.

Well . . . if it's approved by two Pauls, I don't know how you could go wrong . . .

Looking forward to this!!

John Brown SuperDork
May 23, 2011 3:44 p.m.

Jeez Doll, your back MUST be feeling better!

MrJoshua SuperDork
May 23, 2011 3:46 p.m.

It should be a neat car when finished. Do you still have the email I sent you a long time ago with thoughts on the swap?

dollraves Reader
May 23, 2011 3:47 p.m.

In reply to MrJoshua:

Resend, please sir! This screen name at the ol' gmail-dot-com. :D

BoxheadTim SuperDork
May 23, 2011 3:47 p.m.

Hmm. There seems to be only one thing missing...

Booooooooooooost.

Good luck with the build!

MrJoshua SuperDork
May 23, 2011 3:48 p.m.

In reply to dollraves:

I will get that to you later on tonight or sometime tomorrow, have to find some time and get my brain back in rotiata mode.

belteshazzar SuperDork
May 23, 2011 4:06 p.m.

I have wanted a rotary miata for some time. sadly, the miata I just bought has a very healthy 1.8 with low-ish miles. I know... I know... Life sucks sometimes.

RossD SuperDork
May 23, 2011 4:16 p.m.

http://www.locostusa.com/forums/viewtopic.php?f=4&t=8008 Here's a locost forum thread talking about swapping the front halves of a 1st gen Rx-7 and a Miata transmission.

friedgreencorrado SuperDork
May 23, 2011 4:41 p.m.

I see that this is a common swap..but I'll bet none of those are sub-$2K. This is gonna be fun!

mtn SuperDork
May 23, 2011 5:00 p.m.
belteshazzar wrote: I have wanted a rotary miata for some time. sadly, the miata I just bought has a very healthy 1.8 with low-ish miles. I know... I know... Life sucks sometimes.

Locost the 1.8?

dollraves Reader
May 23, 2011 5:13 p.m.
belteshazzar wrote: I have wanted a rotary miata for some time. sadly, the miata I just bought has a very healthy 1.8 with low-ish miles. I know... I know... Life sucks sometimes.

That's perfect, though! Start racking up the miles, and in a few years, look for a low-mileage RX-8 on Craigslist. ;)

dollraves Reader
May 23, 2011 5:17 p.m.
RossD wrote: http://www.locostusa.com/forums/viewtopic.php?f=4&t=8008 Here's a locost forum thread talking about swapping the front halves of a 1st gen Rx-7 and a Miata transmission.

HA! Great minds and all that...this is a quality bit of info that Paul Elenga imparted. I definitely want to keep the Miata gearing, and should (in theory) keep me from having to break into the firewall.

MrJoshua SuperDork
May 23, 2011 6:11 p.m.

Swapping the Miata tailshaft onto the RX7 transmission will help you keep the Power Plant Frame and eliminate the need to fab up transmission mounts or front diff mounts. The downsides are that you are stuck with wherever that leaves you motor position wise. I think interference with the crossmember/front subframe might be an issue. The other issue is the PPF runs down the right side of the tunnel where the RX7 exhaust wants to run.
The swap should produce a hell of a car. My Challenge Miata was well under 2000lbs with a turbo and front mount. Yours should beat that handily.

May 23, 2011 6:33 p.m.

What I'm finding scary is that I had this exact build in my head this past weekend.

JtspellS Reader
May 23, 2011 6:44 p.m.

This sounds like the best build i have heard in a while, i sir wish you luck and keep us updated.

dollraves Reader
May 23, 2011 7:12 p.m.
JtspellS wrote: This sounds like the best build i have heard in a while, i sir wish you luck and keep us updated.

-cough- That's "miss." :D

-Doll

dollraves Reader
May 23, 2011 7:15 p.m.
dollraves wrote: -*cough*- That's "miss." :D -Doll

Well, MS., if you're nasty...

alfadriver SuperDork
May 23, 2011 7:21 p.m.

So you wake up from surgery, which was a good idea.

And still think that someting SVRX said was a good idea?

Man, the drugs did a number on you.

But, when you get this done, you will be quite the expert. Good luck with it!!

turbojunker HalfDork
May 23, 2011 7:22 p.m.

Since that's a Series 5, you should be able to recoup a significant portion of that $700 by selling the taillights, spoiler, mirrors, bumpers, and radio surround. Hopefully those pieces are still good.

dollraves Reader
May 23, 2011 7:36 p.m.
turbojunker wrote: Since that's a Series 5, you should be able to recoup a significant portion of that $700 by selling the taillights, spoiler, mirrors, bumpers, and radio surround. Hopefully those pieces are still good.

Taillights: Destroyed.

Spoiler: Destroyed.

Mirrors: Salvageable (driver), missing (passenger).

Bumbers...maybe salvageable with a touch of bondo and some paint.

Radio: Salvageable!

[Edited once I took another look at the car...]

I'll post better pix of the damage. I'm not kidding when I say this body is TOAST. The kid had it on CL for several weeks before I went to look at it. The engine and interior are pretty much the only bits worth saving.

dollraves Reader
May 23, 2011 7:38 p.m.
alfadriver wrote: So you wake up from surgery, which was a good idea. And still think that someting SVRX said was a good idea? Man, the drugs did a number on you. But, when you get this done, you will be quite the expert. Good luck with it!!

Oh, I never thought it was a good idea. I just didn't have any betters ones that came to fruition. ;)

amg_rx7 HalfDork
May 23, 2011 11:03 p.m.

I've always wanted a rotary miata as well. My RX7 is heading to Paul next week coincidentally...

Let me know if you need a hand.

dollraves Reader
May 24, 2011 12:26 a.m.

@amg_rx7: If you're willing to school a total rotary newb, you're welcome to come on over to any time! :D

More pics of the RX-7 damage are on my flickr.

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