How I Built a late model REPU 

I love building things and automobiles are no different. 

This is a detailed living document about my 1989 Mazda B-Series REPU. 

Where this story begins is when I was in college and got hooked by this beautiful blue eyed Blonde free spirited woman (we got married before this truck came around). When we were dating, this 1989 Mazda B2200 lived across the street from her parents house and I've always had a soft spot for small single cab short bed trucks. While we moved around the country, my love for Mazda and rotary engines grew. We came back to Kansas to celebrate Christmas with her family years later and I noticed that the little Mazda Truck wasn't parked on the street where it had always been. After the family activities were over, I caught the neighbor outside and asked about the truck. She replied “it's just in the back yard and we are thinking about selling it.” 

With that info,  I asked to take it for a test drive and was prepared to offer nothing more than $500 (my recent Christmas money, not expecting the offer to be accepted). I quickly found myself the proud owner of a tired 1989 Mazda B2200 with 114000 miles. 

Realizing, now we had to drive 8 hrs back to Minnesota in the winter and I just bought a truck. We drove the truck to my parents house the next day to celebrate with them and I went down to the local Tire store and purchased 4 all terrain tires at the tune of $650. Then changed all the fluids, filters, replaced some light bulbs and we were ready! We were not ready….

In the Beginning

On a warm winter day

Beautiful..... 4 missed matched tires and a blown out bench seat.

New Daily Driver

Daily Driver

I daily drove the truck all through the winter with no issues. Then we decided it would be a fun road trip to Oregon! So I threw more parts at it, shocks, brakes, topper, seat covers etc. That trip totaled 2500 miles and on the way home the truck lost power and began to smoke more and more. 7 qts of oil were burned or leaked out during that trip and it only got worse after we got home. So I started to plan a tune up. 

We moved again back to Kansas this time and I finally had a large enough work space to begin the rebuild, at the sheds once again. After compression testing and looking online for parts I determined the 2.2L 4 cylinder needed a full overhaul. Which didn't sound exciting. I started calling friends looking for a donor….a 13b rotary engine and trans! 

Out with the Pistons

Rotary Time

A good friend of mine from up north gave me a S4 13b 6 port engine and transmission. We made a road trip back up to Minnesota and put all the engine and transmission in the back of our Mazda3. So by this point, I was well into the rust repair on the truck, after driving it though one Minnesota winter the rust progressed a lot. I had to patch the drivers and passenger floor pan near the front cab mounts and both rockers had small holes starting. Ended up being a lot worse than I thought. Once I had that all finished, it was time to pull the 4 cylinder and begin the real fabrication. 

My intention was to give the truck new life without the minimum modifications, simultaneously upgrading the power. Through my research and discovery most people who has donethis swap, moved the shifter location back at least 6in. Which puts the shifter next to the driver rather than slightly in front of the seat. I wanted to keep the bench seat for now so that was my jumping off point. I mocked up the engine and transmission together and dropped it in the chassis of the truck. I quickly discovered to have the shifter come through the original tunnel hole that put the front of the engine where the radiator mounts. The truck's transmission will not bolt to the rotary engine because the bell housings are different. I found some people moved the shifter location forward on a RX7 transmission by cutting the shifter housing and tube to move it forward about 6in. People were mainly doing this on Rotary Miata swaps. With all my measurements I needed to move it more than 6in.  I took both transmissions apart and discovered the center of the transmissions share the same bolt pattern. I used the front half of the FC RX7 transmission and the back tail housing of the truck transmission with the shifting rods and forks from the truck's transmission. This moved my shifter location forward towards the engine 9in. Success! 

Street Ported Intake and Exhaust

Turbo2 Exhaust Sleeves added

Final Mockup Complete

S4 13b 6-Port Block with S5 intake manifold

Fabrication Continues

Also since the tail housing of the transmission is essentially in the same location as it was with the 4 cylinder engine the Drive shaft did not need any modifications! 

Now with the mismatched transmission putting my shifter location right where I wanted it. A few more mockups were needed. I put the original transmission cross member in place and the holes were closed but the engine was far from level. I couldn't lower the engine anymore because of the frame cross member in the engine bay. It's a part of the torsion bar suspension so that was my limiting factor there. I placed the engine 1in above that cross member and made a spacer out of square tubing to lift the back of the transmission to level out the engine. One problem solved created another space issue. Now the clutch slave cylinder was hitting the trans tunnel and the starter was super tight against it too. 

At that moment I really didn't worry too much about it because I still needed engine mounts….

I went back and forth on how to use the original S4 13b engine mounts, everything was in the way. Almost every rotary swapped B-series I found photos of used a 12a front cover and mounted the engine that way. 

In the early spring I made a trip to a salvage yard where I knew there was an FB RX7. To find a donor engine. Thank god these engines are light. The car was buried in a sea of cars, no way to drag an engine hoist in there. So we gathered a ton of chunks of concrete, blocked the whole car high enough off the ground to drop the engine and transmission out the bottom of the car. Drug it out from under there, wrapped a chain around it and with a steel pipe me and my buddy carried it 50 yards like a prised cooked hog ready for feast. Heaved it into the back of a ford Escape along with everything we could possibly take from that car. 

Now that I had a front cover to mount the engine from. I ordered a universal LS engine mount kit from summit racing that had poly bushings and trimmed it way down with the cutting torch. Used the 12a front engine mount, cut the ends of it off and pieced it together with the new LS mounts. Constantly measuring side to side to make sure the engine was centered between the frame rails. Tacked it together in place. When I was happy with all that, I pulled the engine again and got my stick welder out and went to town. At that point there was no going back, I cut the original 4 cylinder engine mounts out and ground everything smooth. 

The biggest issue with this swap was dealing with everything being on the opposite side compared to the 4 cylinder. The exhaust, the starter, the clutch slave, it's all flipped to the other side. To solve the clutch slave fitment issue, I ground down the throwout bear fork around where the slave cylinder pushes on it. Then loved on the tunnel with a hammer and a torch to make more room for the clutch slave cylinder to actuate and for the starter to have more room. It's still tight though nothing hits and I can remove the starter by itself. 

Then came the custom exhaust system, I got a Racing Beat DIY header to start with. It came with pre-bent heavy walled 2in tubing that's long on both ends. With minimal cutting I got the tubes to clear everything and made my own collector out of a 2.5in tube. I made one side of the 2.5in tube oval shaped and trimmed the 2in header tubes to combine into that smoothly. The other challenge was the fuel tank is on the same side as the new exhaust. Which made the fuel lines close to the header, I pushed them around and fabricated the header in a way to be as far away as possible. I decided to make the exhaust cross under the drive shaft to avoid being close to the fuel tank and routed it up over the axle and out the back. I used a Vibrant Performance resonator and muffler. 

No Bolt on parts here

The Vision

After many sleepless nights trying to decide what kind of fuel delivery system I wanted, Carburetor or EFI. My buddy offered me his S5 intake manifold and that decision set the tone for the whole build going forward. I got this crazy idea to look at this build through the lens of Mazda, as if Mazda built a Rotary Engine Pickup in 1989. Now I had the intake manifold and engine used in that year of RX7. I set out to find an Airbox for the intake and that meant the battery had to move to the other side of the engine bay as well. So the Fabrication continued… 

I used a FC battery tray to mount the battery on the drivers side of the engine bay and made mounting brackets for the air box to live where the old battery was. I was able to leave everything else in the engine bay in its original location. 

Final mock up was DONE! Now to the fun part, rebuilding the engine and modifying it. I did a complete overhaul on the 13b, Rotary Aviation Apex Seals, Race rotor bearings and eccentric shaft bearings. I Street Ported the Exhaust ports and installed Turbo2 exhaust sleeves. Street ported the Primary intake ports and I cleaned up the secondary intake ports. I figured they are 6 Port intake runners so they will already flow a lot of air and I was planning on daily driving the truck. So fuel economy and driveability was on my mind. Upgraded the oil pressure regulator to a FD high pressure regulator. I port matched the S5 intake manifold to the block and itself. I had a buddy paint the housings for me with gray Gun Kote to give it an OEM look. I had almost everything ready to assemble then I got word that I was being kicked out of my storage unit…..that's a story for another day. 

Built the engine and assembled the entire truck in under 24hrs to be able to move out of that space real quick. That sucked. Everything is always working out for me. Found another space to rent a few months later and trailer the truck there and continued where I left off. Next was the radiator and oil cooler. 

Got a FB RX7 Aluminum Radiator from Champion Radiator and made some brackets to mount in. Also got a Spall electric fan from them too. Had another buddy of mine make a custom aluminum fan shroud for it so everything would clear the front of the engine. Got a small oil cooler from Summit Racing and all my AN fittings to make oil cooler lines. All that's left is wiring! 

Wiring the MAXX ECU was simple

A lot more than Anticipated

Ordered a MAXXECU from my guy David at EP Machine in California. He made me a flying lead harness to get the wiring game started. I ended up getting a fuse block with built in relays from Amazon (not the best quality) and ordered all my wires and connectors from Corsa Wiring. Mounted the new fuse block in the engine bay and went to town terminating wires with Deutsch connectors everywhere. 

This was my first Stand Alone project so there was a learning curve forsure. I tried to power everything off the truck's original fuse block, though it was difficult to find a good power source, not to mention a place to put relays. The whole 1st half of installing the flying lead harness, I was fighting a faulty ignition switch too. It had to be fixed a few times before it was reliable again. 

The fuel pump was an interesting one, with the Fuel injection intake now installed. I needed a high pressure pump and I discovered later years of B-series trucks were EFI. So I found a used OEM pump and sending unit to drop in the tank. That pump was only good to 40 psi for the 4 cylinder engine, not enough for my rotary. I Modified it with an OEM Mazda RX7 fuel pump in its place. Ran power to it and dropped it in the OEM fuel tank. 

All the little things add up and stack up at the very end of a large project. Once all the vacuum lines and coolant lines and oil lines were all made and hooked up. David sent me a base map that was close enough to get the engine started for the First TIME! Glorious day. After a brake job and a lot of laptop time I could finally drive my little Mazda truck again. 

Since then I have upgraded the headlights to RX Lights FC headlamps. Amazing! Going to work with him on a custom set of taillights for the truck here soon. Did a whole video on that install and review of the lights on youtube.

 

Daily Driver once again!

Installed electronic ⅚ port actuators to make those work. The install was super easy and anyone could do it on their FC Rx7 or Rotary swapped automobiles very easily. I purchased a kit from JAFA Engineering through Facebook. Now we are daily driving again and taking to shows and all over the place! 

end point

Infini REPU

I envision a REPU that's just as fast as a stock FC T2, and look like a 1990s sports truck.

Example of a Infini Fc Rx7

Rare Bird

In 1990 Mazda released a Japanese-Only Market Rx-7 Infini IV. A special edition high performance package for the FC RX7. It is stripped down Turbo2 model with twin-turbochargers and a performance exhaust, suspension upgrades including strut bars front and rear, Ground FX kit and BBS wheels. The interior was also special with a Momo steering wheel, Special bucket seats.

The Latest

Side Quest

As part of the period correct build, I thought a cab spolier would be fitting for my Infini REPU Aero Package. This LUND Cab spoiler is going to get restored and modified to add to the vibe 1990s vibe.

Adventures with my REPU

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