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In September 2007, I was driving past a local wrecking yard on the way to a customers place when I noticed what at first appared to be an old Datsun sitting out front, ready to be crushed. As I circled around I realized that it wasn't a Datsun at all, as in the trunk I could see a distinct baby blue "Mazda Rotary Engine" air cleaner. What was it? An RX-3? An RX-4? No, not quite. It was an RX-5 Cosmo!
Immediately I went into the office and started asking about the car. They were amazed that someone was interested in "that old Mazda", and were happy to sell it to me as long as I understood the sale was "as is". "As is" was an apt description becuase the car appeared to be halfway through an a paint job, in primer, with much of the trim and exterior components removed. It took about a week for them to track down the registration but soon enough the car was in my posession. At the time I had several other projects on the go (not the least of which was Project Tina) so the car sat in storage, waiting.
Almost exactly three years later, in September 2010, it was towed to my shop and I begain work. My vision for the car is both restoration and modernization, known to some as "restomodding". The idea is modernize and modify the car, but at the same time, not destroy the originality and feel of the vehicle. To accomplish that, my goals are to smooth out the body lines, remove the excessive trim (and there is a lot of it), fix any of the mechanical issues, convert many of the manual functions to power and upgrade the 13B 4 port rotary to a 13B 6 port fuel injected and turbocharged rotary. The paint decision has not quite been finalized though I am looking towards a dark metallic blue with a complimentary dark marron interior, and of course a nice set of wheels in the 18" to 19" range. Additionally, I'll be improving both the ride and handling with an air suspension.
While this is far from my first automotive project, it is my first restoration project involving everything from mechanicals, to sheet metal, to upholstry. Additionally it has become a bit of a scavenger hunt as there were very few of these vehicles sold in North America. Some estimates are as low as about 60 Cosmos from 1976-1978, but more realistically it is probably a few hundred.
I have decided that instead of creating lengthy writeups full of pictures like I did with my RX-7, I will document this project by making a series of videos covering the process. I am releasing these videos and posting them to YouTube regularily as the project progresses. If you want to follow the project you can subscribe to my YouTube channel or check back here often to view new videos as they are posted below.
| The Restoration Videos |
| Monday, September 20, 2010 | Part 1: My 76 Mazda RX-5 Cosmo Restoration - Initial Cleanup | ||
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This is part 1 of a series of videos detailing the resto-modding of my 1976 Mazda RX-5 Cosmo project car. Purchased from a local wrecking yard in Sept. 2007 and stored until Sept. 2010, the car was someone else's abandoned project. I got it with body work half complete and in primer, with much of the interior and exterior disassembled. I'm resto-modding the car with some modern touches while remaining true to the original car. In this video, the car is cleaned out after being brought to my shop (yeah, there's like 5 minutes of vacuuming, but it's entertaining). There were approximately 60 of these cars sold in North America! | ||
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| Monday, September 27, 2010 | Part 2: My 76 Mazda RX-5 Cosmo Restoration - Engine Removal | ||
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This is the 2nd set in a series of videos covering the restomodding of my 1976 Mazda Cosmo. In this video, the engine is stripped down and removed from the car along with the transmission. There isn't really anything wrong with this 4 port 13B, but the car needs a little more power (stock is about 120HP) so I will be using this engine to build a 6 port 13B turbo using the Cosmo housings and GSL-SE end plates. | ||
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| Tuesday, October 05, 2010 | Part 3: My 76 RX-5 Cosmo Restoration - Rotary Engine Disassembly And Cleaning | ||
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Part 3 of my Cosmo restoration shows disassembly of the 4 port 13B rotary engine and the beginning of the long process of cleaning the internal engine parts. At first I was quite worried about the condition of the engine after looking through the exhaust ports, but as soon as I opened it up I was pleasantly surprised. | ||
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| Monday, October 11, 2010 | Part 4: My 76 Mazda RX-5 Cosmo Restoration - Engine Cleaning Continued | ||
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In part 4 of my Cosmo restoration, I continue cleaning the engine components, a task which was started in the last video. It is actually quite involved to clean and inspect the internal engine parts and it can easily take more time then it does to disassemble and build the engine. While I did clean all the parts from the 4 port Cosmo 13B, I will only be using the housings, oil pan and a few other components. The rest of the engine will be the irons and rotating assembly from a GSL-SE 13B. | ||
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| Sunday, October 24, 2010 | Part 5: My 76 Mazda RX-5 Cosmo Restoration - Shaving Holes and Minor Floor Repair | ||
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I'm taking a little break from engine work, so part 5 of my 76 RX-5 Cosmo restoration deals with some minor body work. In this video I shave the antenna and sill trim holes, then repair a small hole in the floor. At the end, there is a rather unpleasant surprise... | ||
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| Monday, November 08, 2010 | Part 6: My 76 Mazda RX-5 Cosmo Restoration - Floor Repair Prep and Blasting | ||
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After discovery of the large hole in the drivers side floor, it became clear that the sheet metal needed some major repairs. So part 6 deals with stripping down the floor to get a clear view of what needs to be repaired and to prep for the actual repairs. In this episode I strip out the sound deadening tar using dry ice, clean up the residue, and then sand blast the floor pan. | ||
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| Saturday, December 04, 2010 | Part 7: My 76 Mazda RX-5 Cosmo Restoration - Intake and Exhaust Porting | ||
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Has it been nearly a month since my last episode? Wow, time does indeed fly. I've been quite busy preparing to build the engine. So in part 7, I cover the intake and exhaust porting. The engine is being built with GSL-SE 6 port plates and the Cosmo rotor housings as the basis for a 6 port turbo setup. This port job is fairly conservative, only opening up the primary ports a little and bringing the exhaust ports close to 2nd gen RX-7 specs. The goal is to maintain fuel economy, low and midrange torque, and idle quality. This episode covers everything involved in porting including: marking out the new ports, grinding the port shape, smoothing the bowls, smoothing port to runner transitions, smoothing the runners, grinding and blending the exhaust ports. | ||
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| Thursday, December 23, 2010 | Part 8: My 76 Mazda RX-5 Cosmo Restoration - Engine Hole Tapping and Painting | ||
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It's a Festivus miracle that I now present Episode 8 of my Cosmo restoration. Now that the engine is fully ported, episode 8 deals with the final prep of those engine parts before engine assembly. In this episode the rear iron and water pump housing are tapped for sensors and fittings, and then all the engine parts are glass bead blasted and then painted with POR-15's engine enamel. Also included: adapting S4 water pump housing to older 13B, tapping rear iron for turbo coolant feed, masking the parts for blasting and painting, final soap and water wash, watching paint dry. | ||
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| Friday, January 14, 2011 | Part 9: My 76 Mazda RX-5 Cosmo Restoration - Shaving The Door Handles | ||
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I've been doing a lot of engine work lately, so for episode 9 I change gears a little and move onto a random task: shaving the door handles. This involves installing a solenoid into the door which will now electrically activate the door latch, and then removing the exterior handle holes from the door. What I thought was a quick task turned out to be more time consuming than I thought due to the difficulty of working inside the door and my lack of sheet metal talent. Included in this episode: installing AutoLoc 50LBs shaved door solenoids, modifying solenoid bracket to fit doors, setting up a pulley mechanism, modifying stock door latches for shaved doors, door window removal, wiring the solenoids, cutting out sheet metal patches for the door handle holes. | ||
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| Wednesday, February 02, 2011 | Part 10: My 76 Mazda RX-5 Cosmo Restoration - Shaved Door Sheet Metal | ||
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In part 10 of my 1976 Mazda Cosmo restoration, I continue the surprisingly long task of shaving the door handles. Last episode I left off after cutting the patch panel to fill the hole in the passenger door. This time I weld the panel in, fix the huge amount of warpage my improper welding technique caused, then do the same on the passenger side. Shaving the door handles took a lot more time than I thought it would and it feels nice to have it all finally done. Included in this episode: patching door handle holes, welding sheet metal, grinding down welds, hammering out warp caused by welding, learning how to not screw it up next time. | ||
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| Tuesday, February 22, 2011 | Part 11: Power Windows Installation - My 76 Mazda RX-5 Cosmo Restoration | ||
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I now present episode 11 of my '76 Mazda RX-5 Cosmo restoration. This episode deals with the task of installing the AutoLoc PW4650 universal power window kit. This kit includes motorized actuators which rotate the existing manual window cranks, driving the manual regulator and thus converting it to power without the need to fit an entirely new window regulator. Additionally it includes all wiring and switches (not installed yet), and mounting brackets. As it is a universal kit, it is universally wrong for every application and must be customized to fit. The installation was straightforward though time consuming. I have to admit, this episode is a monstrosity and quite a bit longer than normal. But for good reason, because I didn't want to do a "To be continued" as the next episode will be quite special. Included in this part: custom fitting AutoLoc universal power window actuators, making cutting channels into the inner door for space, patching and finishing off the channels with welding and sheet metal, cutting sheet metal from templates, media blasting before painting, making brackets for actuators, a surprise at the end. | ||
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| Thursday, March 10, 2011 | Part 12: 13B Rotary Engine Rebuild - My 76 Mazda RX-5 Cosmo Restoration | ||
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Just as I promised last episode, it is finally time to build the engine! Part 12 of my RX-5 Cosmo restoration covers the entire process of building the 6 port 13B Mazda rotary engine. While this engine is a hybrid of GSL-SE RX-7 and Cosmo parts, the process is the same for any rotary from a 12A to a 13B NA, 13B Turbo, 13B-REW or any other variant of the 13B. This video shows the whole process of the engine build, starting from measuring the rotors and covering everything else including clearancing the side seals, assembling the rotors, complete assembly the short block, setting the eccentric shaft end play and installing the front cover and everything underneath it. It's probably the most complete engine build video outside of what you can buy from the vendors, and as such, is an hour long. After this one, I'm going back to videos under 20 minutes. But for now, grab a beverage of your choice, sit back, and enjoy. | ||
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| Monday, April 04, 2011 | Part 13: Clearing The Engine Bay - My 76 Mazda RX-5 Cosmo Restoration | ||
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With the engine built, it seemed logical to focus a bit on where that engine is to live: under the hood. Episode 13 has me stripping all the remaining mechanical components out of the engine bay in preparation for it to be blasted, repaired and painted. This is dirty grunt work, not particularly stimulating but at least it isn't sheet metal. It's been a while since my last update and rest assured, what you see here is only a small fraction of what has been done. I have plenty more footage ready to edit. Included in this episode: removing all engine bay mechanical components, removing brake lines and cylinders, labelling and removing wiring harnesses, removal of the steering gear, orderly disassembly of an engine bay. | ||
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| Monday, April 18, 2011 | Part 14: Oil Pan! Engine Bay! Floor! - My 76 Mazda RX-5 Cosmo Restoration | ||
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Part 14 of my '76 RX-5 Cosmo restoration is a collection of three random tasks. First, I add a -10 AN fitting to the oil pan to serve as a turbo oil drain. Next, I continue stripping down the engine bay by scraping off the undercoating and then cleaning off the residue with kerosene. Finally, I begin some of the work on the floor by patching a small area on the drivers side of the transmission tunnel. Included in this episode: drilling a turbo oil drain hole in the oil pan, TIG welding a -10 AN flare to the pan, scraping engine bay undercoating, trying to clean it with Castrol Super Clean, cleaning the residue with kerosene, finding a few rust holes, cutting out a rusted area of the transmission tunnel, fabricating a patch panel, welding it in place, grinding the welds. | ||
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| Friday, May 13, 2011 | Part 15: Repairing The Transmission Tunnel - My 76 Mazda RX-5 Cosmo Restoration | ||
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Happy Friday everyone! It's been a little while since my last video as I've been busy with beginning-of-season related activities: built a new air compressor for the shop, put a new diff in my RX-7 and helped someone else with an engine installation. It's taken a while to edit episode 15 (the actual work was completed in March) but it's finally here! In part 15, I repair the rust damaged areas of the transmission tunnel discovered during blasting. The sheet metal surrounding the shifter hole and parking brake handle area is cut out, patch panels are made and then welded into place. Also a cracked driver side seat mount is repaired. Sheet metal work is time consuming though not necessarily difficult and this is only a little work of much to come. Included in this episode: cutting out rusted metal, making templates, cutting patch panels, forming patch panels, welding in patch panels, blasting rusty parts, repairing damaged brackets, removing spot welds and replacing, lots of grinding. | ||
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| Sunday, June 19, 2011 | Part 16: Front End Disassembly, Wheel Well Un-Gooing, Dash Removal - My 76 Cosmo RX-5 Restoration | ||
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I finally present part 16 of my Cosmo restoration! Has it really been over a month since the last update? I guess I've been busier than I thought and haven't had as much time to work on the car as I would have liked. Regardless, work has been slow and steady when I could find a few minutes here and there to spend in the shop. The work that has been accomplished lately has mainly been grunt work, as shown. In this episode I disassemble the front end, revealing the need for more rust repairs. The front subframe is removed before the wheel wells are cleaned up in preparation for media blasting. Then since I've been putting it off for months, the dashboard is removed as well as under dash components. Included in this episode: front fender removal, nose cone removal, front subframe removal, stabilizer bar removal, scraping wheel well undercoating, undercoating removal with kerosene, rust, dash board removal, heater core removal, heater components disassembly. | ||
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| Tuesday, July 26, 2011 | Part 17: My 76 Mazda RX-5 Cosmo Restoration - Rear Passenger Floor Sheet Metal Repair | ||
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Episode 17 of my '76 Mazda RX-5 Cosmo restoration moves from the destruction of the last episode to construction as I focus mainly on one task: repairing the floor in the rear passenger seat area. This was some of the surprise damage I found while sand blasting way back in part 6. I've been neglecting the floor for more interesting tasks and because rust is depressing but after uncovering far more tin-worm damage in part 16, I decided it was time to do a little more sheet metal work. This turned out to take longer than I thought and was a rather tedious area to work in. Included in this episode: cutting out rusty sheet metal, cleaning up rust, prepping the areas for repair, fabricating patch panels, media blasting, hand forming patch panels, welding in new metal patch panels, recreating factory beads without a bead roller, corpse removal. | ||
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| Monday, September 05, 2011 | Part 18: Floor, Frame, Firewall - My 76 Mazda RX-5 Cosmo Restoration | ||
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It's time finally for part 18 of my Mazda RX-5 Cosmo restoration. In episode 19 I continue repairing the rear floor pan, this time dealing with the drivers rear seat area as well as some of the bulkhead and frame below it. Once tired of messing about with floor pans, I move onto some easy sheet metal work involving filling some of the unnecessary holes in the firewall. Included in this episode: cutting out rusty sheet metal, cleaning up rust, prepping the areas for repair, fabricating patch panels, hand forming patch panels, welding in new metal patch panels, smoothing a firewall, fixing sheet metal weld distortion, a tornado. | ||
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| Monday, December 05, 2011 | Part 19: Front Inner Fender Removal, POR-15, Rear Sill Repair - My 76 Mazda RX-5 Cosmo Restoration | ||
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Part 19 of my '76 RX-5 Cosmo restoration continues with sheet metal repairs, but hopefully in a less boring format. First off I totally remove the rotted out front inner fenders by drilling out about a billion spot welds. Then we move onto the very complicated rear inner sill repair. This brings the introduction of POR-15, the first time I have used it on this project and by far, not the last. Included are many tips on working with this product. I promised less sheet metal, but wanted to show the rear inner sill repair because it was by far the most complicated sheet metal repair I have yet done on this car, and likely will remain as such. Included in this episode: drilling out spot welds, air hammering off panels, using MetalReady to prep for POR-15, applying POR-15, POR-15 usage tips, cutting out floor to access rear inner sill, fabricating a new rear inner sill panel, welding it all back into place, nudity of me. | ||
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| Sunday, December 25, 2011 | Part 20: Media Blasting The Front End - My 76 Mazda RX-5 Cosmo Restoration | ||
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Merry Christmas everyone! It's about that time in the day where one starts to get tired of their crazy extended family, so to brighten the mood with a distraction, here's Episode 20 of my '76 Cosmo Restoration. In part 20, I media blast the front end and engine bay, removing 35 years of rust, gunk and dirt. Then POR-15's MetalReady is used to preserve the freshly blasted sheet metal and prevent surface rust from forming while the repairs are performed. So grab that new tablet or laptop, sit down with an adult beverage and enjoy. Included in this episode: making a blasting tent to contain the mess, info about media blasting, blasting the front end including inner fenders, wheel wells, frame and engine bay, and using MetalReady to prevent flash rust on the fresh metal. | ||
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| Thursday, April 05, 2012 | Part 21: Front Sheet Metal Extravaganza 1 - My 76 Mazda RX-5 Cosmo Restoration | ||
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Part 21 is finally here! It's been quite a while since the last episode, and a lot has been accomplished. Not quite as much as I would have expected due to a busy time of year. After a trip to Jamaica at the beginning of February kept me out of the shop for two weeks, we entered auto show season with an auto show every weekend until mid March. Now that's over with, I've been able to get back down to the oh-so-fun sheet metal work. This episode focuses on the mass amount of front end sheet metal repairs in the fender and passenger foot well/sill area. Episode 21 is actually only the first part to this set of repairs, which we will finish off in part 22. And after that, no more sheet metal for a while! I promise! Included in this episode: cutting out rusted metal, drilling spot welds, loads of patch panel fabrication, welding it all together, weld through primer, POR-15, grinding. | ||
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| Monday, June 04, 2012 | Part 22 - Front Sheet Metal Extravaganza 2 - My 76 Mazda RX-5 Cosmo Restoration | ||
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Part 22 of my '76 Mazda RX-7 Cosmo restoration finishes up the passenger side front sheet metal. In this episode I reconstruct the passenger front inner and outer sill, floor and kick panel. And the great thing is that as promised, this is the last sheet metal episode for a long, long time! While I have the same set of repairs to do on the driver side, that will all be done off camera so that the next episode gets to the good stuff. Included in this episode: making templates, fabricating patch panels, POR-15, cutting, grinding, welding, floor pan repair. | ||
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| Wednesday, November 21, 2012 | Part 22.5: Updates, Q and A, Misc - My 76 Mazda RX-5 Cosmo Restoration | ||
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June, July, August, September, October and November; Hey, I wasn't kidding when I said in episode 22 that it would be a bit of a wait for the next one! In that time I've been as hard at work on the Cosmo as I could manage, which unfortunately is not as much as I would have liked. It's been a busy summer with plenty taking me out of the shop. Even still, I've been working as much as I can and have picked up the pace over the last two months to the point where the driver side sheet metal is almost done. So what's in this episode, strangely titled as "Part 22.5"? Well, with the help of my special guest Rose Cora Perry, I answer some of the most common questions about the project. And along the way, there are a few tips and tricks thrown in, as well as a little bit of why the driver side repairs have taken so long. This episode is a little different, so I hope you enjoy... | ||
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| Sunday, February 03, 2013 | Part 23: Middle Intake Manifold Fabrication - My 76 Mazda RX-5 Cosmo Restoration | ||
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After part 22.5 was posted, it took the remainder of November and December to finish the driver side sheet metal. I worked my butt off to get it done before January 1st, and indeed, accomplished that task so I was able to start the new year sheet metal free! So I am happy to say that episode 23 is sheet metal free! In this episode I fabricate the parts necessary for my unique combination of intake manifolds, combining an FD RX-7 upper intake with an GSL-SE RX-7 lower intake. Doing so requires the fabrication of a custom middle intake manifold out of aluminium, complete with provisions for secondary fuel injectors. You'll see me build flanges from scratch (using my new drill press), measure and cut intake runners, TIG weld it all together, port match the flanges to the gaskets and runners, install injector bungs, curse at the difficult welding I caused, add -6 AN bungs to a stock RX-7 primary fuel rail, and build a fuel rail for the newly fabricated manifold. I'd like to thank DIYAutoTune for supporting this project and providing some of the parts used in this episode. | ||
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| Sunday, March 17, 2013 | Part 24: MegaSquirt MS3-Pro Installation - My 76 Mazda RX-5 Cosmo Restoration | ||
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Part 24 of my '76 Cosmo restoration is here! And I'm going to come right out and warn you; this is a long one. There is a lot of detail here, for you see, this episode covers in it's entirety the installation of the MegaSquirt MS3-Pro EFI system. Like the engine build in part 12, I decided to cover the entire process in a way that would help anyone performing a similar installation. And while this specifically covers the MS3-Pro, all the information is valid for any MegaSquirt installation and indeed, any other brand of standalone as well. In this episode you'll see from scratch the MS3-Pro installation from bare engine bay to fully wired and functional EFI system. Included is detailed coverage of making an ECU mounting panel, wiring in all the injectors and sensors, wiring up the 2nd gen RX-7 CAS and coils, boost solenoid, e-fan relays and other EFI related accessories. So pour yourself a big drink, get comfortable, and enjoy. A huge thanks goes out to DIYAutoTune for providing the MS3-Pro and other parts used in this installation. | ||
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| Saturday, April 20, 2013 | Part 25: Turbo Manifold Fabrication - My 76 Mazda RX-5 Cosmo Restoration | ||
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Episode 25 of my '76 Mazda RX-5 Cosmo restoration is another long one, covering in its entirety the fabrication of the turbocharger manifold. Suddenly the engine bay started to look a little cramped when I began to position the GT3076R, so it took some plumbing to build the required manifold. Constructed out of 1.5" SCH40 304 stainless steel pipe, it was fully TIG welded with an argon back purge. Yes, this is another long episode because I wanted to show the manifold fabrication process in glorious detail so that this video would be a useful resource for anyone wanting to build a custom turbo manifold. So as I say, grab your favourite adult beverage, sit back, and enjoy. Included in this episode: fabricating a 13B exhaust flange, fabbing a merge collector, positioning a turbo in the engine bay, measuring, cutting and fitting stainless pipe and els, tacking in position, setting up a back purge, final welding, port matching, custom heat shields. A huge thank you to ATP Turbo for helping out with some of the parts used in this episode. | ||
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