1973 RX3 project

[j_man1100]

Hey Guys

Just wanted to share my build here. I know it’s not exactly the status quo around here but I’ve had a lot of inspiration from this forum over the years.

The plan:
I’ve had a lot of Mazda Rotary’s over the years. I bought this car about 14 years ago with big plans for it but never the time or budget. In retrospect, I’m glad because the plans I had as an 18 year old are not what I want now. I’m taking the pro touring approach in keeping it a classic car on the outside but a modern driver. So how to make an old Mazda drive like a new Mazda? Easy. Everything under the body new. Easy right?

Here’s what I brought to Sean at Better Motorsports just out side of Ottawa in Canada. Sorry I don’t have better pics, but that was my jumping off point

[j_man1100]

So I bought a rusty miata and scavenged all the subframes and suspension bits. This car was going to see a completely new suspension from a modern car that has enough aftermarket to keep it alive forever. So after some measuring and some creativity, Sean made it happen. It took some problem solving on his end but he ended up making it all fit and look great. The one thing we did that wasn’t originally planned, but worked out great, is using QA1 coil overs in order to not have to build stock shock towers to fit. So that saved some time and headaches. There was also some rust repair he had to do. A surprise to nobody who’s ever had an old Japanese car.

[j_man1100]

At this point I had decided on my motor. A 3 rotor Mazda 20b. They were never available in North America so I bought one from a shop that had it imported years ago. They’re fairly hard to come by and the price reflects that. In stock form they came twin turbo. I plan to run it naturally aspirated but built up a little which should have no problems doing 300-350hp to the wheels. Sean made up motor mounts and got going on the rear end. While the rear was maybe a bit more work he seemed to have a plan for that from the get go.

[j_man1100]

So nearing the end of the time Sean had it, he closed in the wheel wells, retrofit the miata brake master and booster, and made the steering shaft. The stock one obviously wasn’t going to work but he managed to make it so I could use the stock shaft inside to car to keep the original appearance. He also had to move a section of the firewall back to accommodate the extra length of the 20b vs the stock 12a.

[j_man1100]

So that’s pretty much where I’m currently at. I’ve not done much work on the car since it came home back in the fall. I’ve moved 500km and the house didn’t have a garage so I bought what’s really just an oversized garden shed. But since this isn’t a long term house, I thought something that was able to move with me or be sold down the road was the best bet. It’s 14x36 so that will do fine for me to work on this project.

Going forward I want to get the flimsy frame rails reinforced and then paint. I’ve been bouncing around a lot of ideas on paint but still undecided.

Wheels have been bought. 15x8 front and 15x9 rears. No tires yet but 225 front and 245 rears will be ordered soon enough. I’ll need those for the body work as I’m sure I’ll need to massage the fenders to fit that much more rubber than stock.

If anyone had any questions, let me know. It’s going to be a long term project but it’s also been a long time coming.

[FLYNAVY53]

Very cool project....I love seeing different stuff on the forum!

[j_man1100]

So just a quick update. Have the new wheels on the car. Have a set of fenders from a car that had raced in a few Canadian series. They look good in the front. Need to flare the back but I knew that already.

Rebuild kit for the motor has been bought and working on options for the trans. I have been considering trying to adapt a c5 rear end. There’s much more room for a transaxle and would help the weight distribution I think. It’s a crazy idea, I know, but wouldn’t it be cool?

Currently waiting for the covid lock down to end so I can get the car out to acid dip. There’s a lot of bondo in spots so I’m thinking instead of trying to sand everything I’ll just go with a dip and know exactly what I have.

Finally, here’s a few recent pics, because who doesn’t like pictures. Some with stock fenders and a couple with the flared fenders.

[ryeguy2006a]

Very cool project! Look into the Z06 that Rob Dahm installed the rotary motor into. I believe that was a C5 and he adapted the stock torque tube to the 13b.

[j_man1100]

Very cool project! Look into the Z06 that Rob Dahm installed the rotary motor into. I believe that was a C5 and he adapted the stock torque tube to the 13b.

One step ahead of you. Haha. I’ve spoke to the shop that’s making the bellhousing to make it all work. Thanks so much though. Glad you like it.

[andrewb70]

Very cool. Looking forward to updates!

Andrew

[slimjim]

This is awesome, I'm surprised there's not more Japanese classics like it here considering they've been doing 'pro-touring' well before muscle cars put a name to it. this will be a great build

[jimco84x]

How did I miss this? I'm dying see where this goes. Down low, fat fenders and 3 rotors at 8000 rpm spitting fireballs on every shift. I can already hear it.

It sucks how expensive 20B's have become. It makes the LS swaps more appealing

Excellent build choice. Keep posting!!!

[j_man1100]

How did I miss this? I'm dying see where this goes. Down low, fat fenders and 3 rotors at 8000 rpm spitting fireballs on every shift. I can already hear it.

It sucks how expensive 20B's have become. It makes the LS swaps more appealing

Excellent build choice. Keep posting!!!

Ya, the 20B’s have got a little out of hand recently. I think I got a decent deal on mine but it was still a bit crazy. But thanks for the encouragement. It will be slow but I’ll keep posting updates as I get more done.

[Peanut1959]

"And now for something completely different..." right?

This kind of odd rod is right up my alley! Subscribed, for sure.

For color, how about a pewter grey metallic with some distinctive non-metallic orange graphics? Maybe something inspired by the factory AAR 'Cuda appearance (see attached). Just a thought.

Have you seen the "Mongrel" build on YouYube? It's a '59 Ford 100E wrapped around Miata mechanicals, being built over in England. I'm not sure if any of that process will apply to your build, but it might be worth checking out.

[j_man1100]

"And now for something completely different..." right?

This kind of odd rod is right up my alley! Subscribed, for sure.

For color, how about a pewter grey metallic with some distinctive non-metallic orange graphics? Maybe something inspired by the factory AAR 'Cuda appearance (see attached). Just a thought.

Have you seen the "Mongrel" build on YouYube? It's a '59 Ford 100E wrapped around Miata mechanicals, being built over in England. I'm not sure if any of that process will apply to your build, but it might be worth checking out.

Haven’t seen the Mongrel build but I may have to check it out. As for the colour, I’m still really up in the air over it. You could be onto something though. Not sure I’d go with orange on the stripe but something along those lines could look really good. And thanks for the subscribe.

[JayinMI]

Haven’t seen the Mongrel build but I may have to check it out. As for the colour, I’m still really up in the air over it. You could be onto something though. Not sure I’d go with orange on the stripe but something along those lines could look really good. And thanks for the subscribe.

The Youtube channel is called "Urchfab" and the dude builds some awesome stuff. Sucks he got screwed by the guy who was supposed to paint it.

Jay

[RMMiller]

The Youtube channel is called "Urchfab" and the dude builds some awesome stuff. Sucks he got screwed by the guy who was supposed to paint it.

Jay

It's a cool build and worth watching. He is not as polished as some channels but I think that's one of the best qualities, he's a lot like many of us but with way more talent in my case!

[68Formula]

Love these. Can't wait to see how it comes out.

[454bug]

Great project!

When I was in high school, I had a ‘73 Mazda 808 which was essentially the same car but with a 4-cylinder engine instead of the rotary engine.

I’m looking forward to your updates!

[j_man1100]

Great project!

When I was in high school, I had a ‘73 Mazda 808 which was essentially the same car but with a 4-cylinder engine instead of the rotary engine.

I’m looking forward to your updates!

Thanks. I actually had a super clean and low mile 808 I’d bought from the same guy this RX3 came from. The 1.6L and 3spd auto made for a boring drive though. I do miss that car. Here’s a pic of it.