1973 RX-3 Wagon - An epitrochoidal descent into madness

Introduction:

I’ve sadly put a bit more thought into how I’d like to introduce and structure this project than a lot of other things I’ve done in my life. Any of you familiar with my meandering writing style on the forum know I have a tendency to repetitively edit posts after hitting the submit button. This isn’t out of fear of being wrong on the internet, but rather an attempt to clean up fragmented thoughts and clarify things after I smash the submit button. Every now and again the thought that I should really put some effort into attempting to become competent writer floats top of my list of priorities. So here’s my initial attempt at it.

The subject of this project is a 1973 RX-3 Rotary Wagon. The RX-3 “Savanna Sports Wagon” was only brought into the US for one year from 1972 to 1973. This is an S124A chassis which means it’s a real deal Savanna Sports Wagon, not an 808 converted to look like one. Since it’s a Series I RX-3 variant, it once played host to a 12A good for about 110 HP in North America. That engine is long gone which left me with a blank slate. More on that in a bit.

I posted a bit about the car when I was looking to buy it, then again shortly after I bought it, but the project has run into roadblocks as my life has been in flux for some time.

The primary issue is that my previous career was a field technician for a DoD contractor. While it was a great job, I spent between 8 and 10 months a year out on the road. The handful of months I was home never really lined up with my friends schedule, from whom I agreed to buy the car, and a severe restriction on project time as I was renovating a house and spending time with my family.

The second reason is that I left aerospace to work in the ERP space just before my son (backup child) was born. So, in addition to moving across the country and a paycut, my spouse and I now have an additional child, another house which needs some work, and the seemingly endless process of settling our first child into the new home.

All that for a forewarning that this build is going to be slow. The car isn’t going to be returned to stock but instead an OEM+ type configuration. I can poach, refurbish, or fabricate-to-fit the vast majority of the parts that are missing but certain items, like all the door seal rubber, appear to only be available from sources located overseas. That drastically increases the price of components so I’ll have to see exactly how inventive I need to get.

So with that out of the way, here’s the story of how this came to be.

Background and Purchase:

Several years ago I was working 3rd shift and, while on the flightline performing some servicing and preflight checks, I was shooting the E36 M3 with a coworker from our other flight test facility who I knew also had an interest in cars. Eventually the subject of who owned the heavily modified Mazdaspeed3 in the parking lot came up and I admitted it was mine.

It turns out that he is a serious rotary fanatic. He owned a number of 60’s and 70’s rotary cars including an RX-2 and an R100. So we started talking rotary cars. He had some stories about what his family had built and we hit it off. I had played with a friends FB in high school, nothing real serious, and was kicking around the idea of buying an FD. I joked that what I really wanted though, was an RX-3 wagon. Someone here on GRM had posted a craigslist ad to a pretty rust eaten one a few months earlier and, for some reason, I was smitten with the idea of owning something which represents that level of automotive absurdity.

He comes back with “I have one in my barn. My brother and I painted it a few years ago but never really did anything with it. It’s missing the engine but are you interested in looking at it and potentially buying it?”

“What? No way.”

He then proceeds to show me a picture of it.

Yea, I’m interested.

Several years go by and we finally meet up to look at it. It’s as described, doesn’t have any rot or crazy bondo slabs, and the interior is pretty much intact. So I agree to buy it but I since I was leaving for a trip either the next day or a few days from then I didn’t have time to arrange transportation.

Fast forward another year or so and I’ve sold the California house and moved to Pennsylvania. My friend gets back from a trip and we line up a truck to bring the car across the country. I insisted it be hauled enclosed as front glass is unobtanium and finally I was able to find a transporter who didn’t just laugh at me. I wish I had the pictures of this but the transporter had the RX-3 in the front of an enclosed trailer with a couple Lamborghinis and a heavily modified Ford GT he was dropping off in Chicago. On delivery, he pulled out some sort of chopped and bagged 50’s Chevy on the way from West Coast Customs to a new buyer here in PA. I’m fairly certain the Mazda wagon was the most worthless thing he ever transported but he was nice enough to laugh and tell me no when I asked.

Anyway, I got it home and it’s sat there for the last year waiting to get started. We’re now something like five years into this and all I’ve accomplished is the receipt of the car and changing the title to my name.

The history of a plan:

When I initially started thinking about how I wanted to put this project together I was pretty well set on a S6 13B-REW. The swap into RX-3’s is pretty straight forward it just typically requires a  turbo II transmission to overcome the weird rear transmission mounts used by the FD RX-7. Seems easy enough, at least as far as engine swaps go.

Unfortunately, my plans for grabbing a cheap Japanese S6 motor online were rudely ruined by a gaggle of eBay sellers who are having some sort of pricing competition listing motors 2x to 3x times over what they were just two years ago. That took the secondary market with it and prices have become stupidly high for used motors of unknown condition. At $1800 I could make a case for the risk as I was going to tear the motor down anyway. At $3600 or $4000 that risk becomes a project killer.

That caused to me to reconsider the path I was on. I was thinking I was going to build a 400 HP turbocharged monster when I bought the car. After looking at it for a bit, considering how I’d actually transfer that power to the ground, and the interior, this was the wrong platform for that application. My personal style is an OEM+ type of look and feel. Improve the handling and mechanicals of the car while only putting forth some subtle cues that things aren’t what they seem. To get the level of grip I think I’d need, the rear tubs would have to be extensively modified to fit wheels larger than the GSL-SE wheels currently on it. That means I’d have to pull the rear seats, which isn’t  an option. I also likely can’t flare outward easily due to how the arch overlaps the rear door.

At that point it seemed like the right thing to do would be to fit a less expensive NA motor into the car which would simplify the plumbing and still offer reasonable gains over the 12A it was initially fitted with. As if the internet read my mind, SpeedHunters posted this at about the same time running on a heavily modified NA 13b. Unfortunately it seems like cheap NA S4’s and S5’s have basically vanished off the face of the planet, or I’m looking in the wrong spots, so onto Plan C.

So onto the backup plan. NA RX-8 motors are still cheap. They suffer from a stigma related to an oiling issue in the first generation but it seems like if you actually take care of them they don’t have too many issues. It was also still possible to pick them up for $1200 to $1800. The bonus was that PAC Performance has been documenting the progress of their 13b-MSP build. In its final naturally aspirated form PAC coaxed 200 whp out of the MSP without any kind of crazy modifications, rebalancing, or lightening. The shop then moved onto building, and giving some consideration to putting together, a 400 whp turbo kit that would have given the 200 whp NA motor enough headroom that I could mess with it further if I ever wanted to.

Link if you want to learn about Project 500.

While I’m fishing around for the quirks of the 13B-MSP and considering pulling the trigger, Andy Neuman chimes in that he’ll sell me a S4 motor, harness, and ECU out of his challenge RX-7 to zero the car out. Apparently he knew where to look for a cheap one... That pretty much cinched the engine choice as it significantly lowers the risk and barrier of entry allowing me to build something fun to drive without breaking the bank. It also allows me to use the stock RX-3 rear end instead of going the cut down Ford 8.8 or Volvo 240 routes I was originally looking into.

The Current Plan:

The goal isn’t to create a track monster. I want a toy that I can drive around on nice days or drive the kids to school to annoy other parents but isn’t going to get me killed merging. Eventually I’d like to take it to the Classic Motorsports Smokey Mountain Tour, so I also want it to be livable for long periods of time. My daughter already loves cars and she appears to be developing the same taste in cars I have. I’m not sure which one of us is in trouble due to that development, but it will be fun to cart her around in something absurd to nurture that interest.

With the drivetrain nailed down, that leaves… well basically everything.

• Everything else that goes in the engine bay. (That’s an exhaustive list and the vast majority of the work)
• Potentially rebuild a motor
• I need a 12A to 13B conversion kit. Calling Racing Beat to see if their RX-7 mount will fit an RX-3. If not PAC Performance sells one.
• All the brake lines have been open for who knows how long. They’re all getting replaced.
• Rear brakes.
• Every weather seal on the car is shot. It appears the only place to get replacements, like basically every other part, is to order them from Australia.
• The rear hatch trim is missing. It appears I can get some off Ebay for about $300. I don’t want the trim that badly so I’ll probably fill the holes and match the paint.
• Dashboard is cracked and need of some love.
• Drivers seat is pretty rough but the rest of the seats are in good shape. There’s a few companies in the area that repair seat covers. I’ll likely ask for a quote to fix it and a quote to put in new centers. The headrest contains some cool embossing so I don’t want to get rid of it if possible.
• Carpet
• Headliner
• Build a center console.
• Run down all the electrical gremlins in a 45 year old car with an engine swap.

The big undecided item right at the moment is the suspension.  

There’s three ways this could go:

1. Stock: It appears that it’s possible to still get new struts and the rest of the wear bits for the suspension and steering.
2. Modified: Techno Toy Tuning offers a pretty nice front end kit with coilovers, a bigger front sway bar, and bump steer correction. The kit appears to be aimed at the track crowd though so I’m not sure it would meet my “livable” requirement.
3. Air: At this point I’m pretty drawn to the idea of air. My driveway is 600 odd feet of gravel up a steep hill. Keeping the nose off the ground is a priority but I like my cars low. I only know a bit about air ride setups, and no one makes a drop in kit, so some fab work and serious research is going to need to happen.

Work Starts

Again, just a warning, the pace on this is going to be glacial. Hopefully this thread gets me off my ass and into the garage at night.

The first thing I do when I buy a car is grab the factory service manuals. I’m not super picky about digital or paper but locating a digital copy of a 1973 RX-3 and it’s electrical diagrams… yea. Off to eBay. 35 dollars later I have an engine manual, REAPS manual, and wiring diagram.

(picture of manuals)

Andy was cool enough to brave dropping off the RX-7 at my house so I could try to test the engine before I pull it.

Things are a bit… shall we say tight, at the top of my driveway. Eventually we were able to get it into the garage by pushing it in most of the way with the Vibe then straight human power. Considering how many non-running cars I bring (or limp) home I should probably just bolt a winch and snatch block to the floor.

Anyway it’s in and I am starting to investigate the motor before pulling it after a pretty significant delay. Which is where I’ll start with updates.

I had my home AC serviced a couple weeks ago. I asked the company that did that to de-service the AC on the RX-7 while they were on site as the RX-7 appears to have an R22 system. They seemed a bit surprised by the request but did it anyway. Doing my part I suppose.

Investigating the RX-7 a couple of things stood out. First off the interior of the car is fantastically well kept and the top of the engine is pretty clean. That was a major factor in purchasing it.

Second when you look a bit closer the front cover has RTV on it. Which means it’s been off at some point. Not uncommon but if it’s just that, there was probably an oil leak at some point.

Third the neck where the water which goes into the housings has RTV and other goo on it. So probably also water leak then. I was half planning on tearing it down anyway so probably not a huge deal since most of that can be hot tanked off.

Pulled the shroud and radiator fan off so I could get at the front of the motor to ensure it turned.

The engine turned ok and seems to have compression so that’s a good thing. So I set to work pulling the radiator and cutting zip ties to liberate the various components I’ll need.

The radiator hoses are held on with worm drive clamps, rather than spring clamps, (or both in this case) and the radiator hoses all appear to be new-ish. So obviously someone did some work to this trying to isolate a leak or other problem.

Coolant was green in the expansion tank, nothing appears to be out of the ordinary there besides being a bit full.

Unfortunately when I pulled the petcock out of the radiator the water was brown and smelled like…. Water. Crap. Looks like it was a cooling problem which adds up based on the work done on that side of the house. Hopefully nothing is cooked but a teardown appears inevitable.

Finished pulling the hoses off the the radiator and neck to find some sort of white waxy goo in the motor with no sign of coolant. If I wasn’t going to rebuild the engine it’s sure as hell getting done now as I'm willing to bet this is some sort of stop leak.

The oil metering pump is also a gigantic mess but it’s the mechanical which was important to me. I'm hoping I can rebuild it because Rotary Aviation makes an add-on which allows users to run two stroke oil in place of the engine oil through the pump. That should clean things up a bit and avoid having to premix when I fuel up.

Goal for tonight is to finish freeing the engine loom and computer as well as uninstalling a few other components.

Oh man I really love these. In for more. 

Side note about wrenching for fun rather than frantic necessity like it’s been over the last two years. I love working on mechanical things in the quiet by myself when there's no pressing timeline. Sometimes I forget that and it takes me a night like last night to remind me.

When I worked as a maintainer I loved working in the quiet of the larger hangars overseas all alone. A lot of other mechanics liked to put music on and perform maintenance, which is fine as I don’t really hear the music anyway when I’m working, but there’s just something about the quiet that really helps with my mood and motivation when I'm facing a long job. Towards the end of my employment I actually used to send my junior guys away and change the Rotax 914’s (the TPE-331’s were too labor intensive to do that) either by myself or with one of my other senior mechanics that also liked the quiet just to get away from my desk.

Right at the moment, since I have a couple of very young kids, any quiet time where someone isn’t grabbing my tools, trying to drink spent fluids, or spilling my “oil-dry” on the floor to make a sand castle, is really appreciated.

Sweet!

The0retical said:The subject of this project is a 1973 RX-3 Rotary Wagon.

Gorgeous looking wagon. The blue looks great on the form. Interesting road up to this point. I LOL'd about the delivery guy and Lamborghini comments. I'll be following along

I love wagons so I'm in to follow along. I'm also making slow progress so I can understand that. 

Disappointing to see the poor work on the RX7 considering the overall condition of the car. 

I cant get over how clean the car is. So, what is the story with the original engine?

Pete

In reply to NOHOME :

Wouldn't doubt it if it failed after 30-40k and the car got forgotten about.  The twin dizzy engines were not very long lived.  Mazda made a point of having a super long warranty post-73 after they fixed the coolant seal and housing chrome issues.

(They used to chrome directly to the aluminum, which is not a good idea...)
 

That weird white goo is dried out coolant.  You should have seen the inside of an engine I got from a GSL-SE that sat in a barn in Texas for 20 years.  The water jackets were full of translucent jelly.  Took forever to clean those things out.

The "white goo" is from Calcium and magnesium, minerals found in hard water, reacting with the coolant's additives (to protect metal surfaces) which forms calcium or magnesium phosphate.    It drops out of old coolant in a gelatin where it's low flow/high heat.   

Change your coolant regularly and use distilled water with quality coolant.....

In reply to Knurled. :

I guess the reason I ask is because I perceive that this was a "Cherished" car to someone, and even if broke,I don't see where the drivetrain would have been binned or lost by accident?

As to it having failed?! I am with Hitler on this one.https://www.youtube.com/watch?v=zxsY4lEGRBI

Andy Neuman said:

Disappointing to see the poor work on the RX7 considering the overall condition of the car. 

Yea the car is in fantastic shape otherwise. I'm not super worried about it as the important part was that the motor didn't lose the apex seals at some point and trash the rotors and housings. Most of the gunk will come off as I'm going to break it completely down and rebuild it. I ran a quick risk analysis when you offered it up.

What it came down to was that I could still likely use the side housings even if the rotor housings and rotors were trashed. If I were to buy a JDM engine for 5x the cost I'd still be running that risk, as no one will warranty one of them, and have even less money to rebuild should I hit the problem.

The alternative was that I buy a rebuilt known good motor for $4500 to $6000 then have to wire it, adapt a transmission, get accessories etc. Which was an even more expensive option.

So even if I come out of the tear down and find it's a catastrophic loss, I'll come out ahead of the other two options.

Sorry it took so long for me to get started, life kind of got in my way. I'll have it ready to pick up in a couple weeks or whenever your busy season ends.

In reply to bOttOmfeeder and Knurled :

Well that makes me feel better that I should be able to get most of it out anyway. It worried me a little when I found the gunk at the highest point of the system. I've torn down more reciprocating aircraft engines than I can count, both water cooled and air cooled but automotive engines, while semi equivalent, tend go a lot longer without the care that I put into my engines. As such I'll probably see some new and interesting things on this journey. Glad you're both following along.

NOHOME said:

I cant get over how clean the car is. So, what is the story with the original engine?

 

Pete

I'm not 100% sure what the story is, I should ask my buddy to chime in here. I know his he, his brother, and father were big into the SoCal rotary scene with the early 70's cars (R100's, RX2's, RX3's and recip 808's). I suspect Knurled is correct that there was a motor failure as the chassis only has 33k and change miles on it.

The California title was dated from 1998, my understanding was that they bought it like that with the intent to restore, they actually did a nice job laying paint on it, but had a bunch of other projects and it was put on the back burner until they decided to downsize the collection a bit and it was offered to me.

I brought it out to the rust belt from it's cush life in Southern California but this thing is only sort of likely to see rain but it'll never see snow or salt. So I expect it to out live me.

NOHOME said:

As to it having failed?! I am with Hitler on this one.https://www.youtube.com/watch?v=zxsY4lEGRBI

Okay that was funny as hell. Lost it at "Not enough torque to pull the panties off your drunken sister."

Awesome project! I love old weird wagons, I'll be following along.

I didn't accomplish anything the night before last as I fell asleep with my daughter. I keep hearing I should try to get as much affection as I can while she's young as eventually she'll grow up a bit and I won't be unquestionably awesome anymore…

Last night I found out why you remove the engine loom as part of the engine assembly rather than independent of the motor. The routing makes it such that you'd have to pull the vast majority of the power steering, fuel, brake, and AC hoses to get to the sensors on the backside. Newer cars are quite a bit better thought out in my opinion. I'll rethink the routing when I install it into the RX3.

Tonight's plan is to the RX7 on jackstands and get the exhaust and prop shaft disconnected. Then I'll need to borrow an engine hoist and  figure out hoist points. I'm doing this an hour or two at a time but progress is progress.

All of 3% of the way done (maybe)

So this thread was supposed to keep me motivated, but it’s just made me realize what a mess my life is with two small children, a “move in ready” house that had some pretty basic stuff neglected, and a job that often requires more mental energy than I can muster some days.

Shortly after my last post, my 1.5 year old decided carrying groceries inside was boring and yanked the hoses connected to the coolant overflow tank, that were tucked into the front of the car, out and siphoned himself off a big old mouthful of coolant. Wife calls me at work, wanting to know what type was coolant was in the car, as she was on the phone with poison control. She wasn't real thrilled when my reply was flatly “Not Dexcool, likely some 50/50 Ethylene Glycol equivalent. The MSDS says to take him to the hospital I'll meet you there to entertain our daughter.” Not real severe poisoning just a couple bags of IV fluid and they held him overnight just to make sure.

Interesting poison control and medical staff side note: Pretty much all involved remarked, more than a few times, about how quickly we got my son to the ER. It took about 35 minutes from ingestion to admittance to the ER with a pediatric unit (hospital is 15 to 20 mins away.) Apparently it's pretty common for people for wait to see if there's any effects before taking the kids in. The staff all seemed a bit surprised when my response was "Well the MSDS does say to seek medical attention immediately. So here we are." That’s kind of horrifying.

Two weeks later my wife ended up having some surprise surgery. She’s alright now but was hurting pretty bad for a while.

All that basically means that the rubber kit from Australia I was eyeing and the rebuild kit for the engine are going on the back burner for a while. There’s plenty of low cost stuff to do on the RX-3 while I try to build up the bank accounts again.

I pulled the wiring loom, computer, prop shaft, and exhaust out of the RX-7 about three weeks ago after everyone was feeling a bit better.

Side Note: If you’re pulling the computer from a 1987 RX-7 the internet says it’s behind the passenger side kick panel. It isn’t. It’s in front of the feet of the passenger up against the firewall.

Pulled the shifter out and disconnected all the rest of the lines required to get the engine out. I couldn’t go any further though because I needed another person on the hoist to help me get the engine out and SWMBO was feeling pretty crappy.

Last week my wife's cousin came over to help me close up the pool and drop a tree which was starting to encroach on the pool. The corner before my house he burst hardline on his 90’s Tahoe. No big deal there’s plenty of places worse to break down than my house and he made it up the driveway safely.

While he closed up the pool I went out, grabbed some new tube, and made him a new hardline. Unfortunately, when we went to bleed the brakes, one of the bleeders was a triangle and the other, well I sheared it off. Even judicious amounts of penetrant couldn’t save us. Since it was 7pm on a Sunday I loaned him the Vibe so he could get to work for the week while new calipers were shipped to my house.

What does this have to do with anything? Well, since he was here this week, I convinced him to help me pull out the engine of the RX-7, along with some help from one of my wife’s brothers, after producing enough beer to have the two of them also help me move a new to me pellet furnace into the basement and replace the Tahoe's front calipers. It was a pretty entertaining day.

Anyway the engine and transmission are now in the corner of my detached garage, the RX-7 is de-engined right after the challenge for Andy, and I can actually start on the RX-3 now.