Kicking off a thread for my rotary swap Spitfire project. After feeling burnt out and very unmotivated with my fleet of projects, I cleared out the yard this summer and decided that I would go all in on a new endeavor. The goal is to use some cash I've saved up from a few years of working to build a car with a clear vision for the end product, instead of random futzing around with cheap and convenient stuff that I could afford on a college student budget.
The first step was acquiring the donors:
Chassis donor, 1978 Spitfire 1500. This late model example has been off the road since the 90s and passed around a few garages best I can tell. It's pretty rough, but all one color and minimal body rust, should come back to life nicely.
Drivetrain donor, 1988 RX7. I tossed around a few ideas here like miata, RX8, or mazda/ford ecoboost family, but ended up grabbing an NA series 4 13b. Running and (barely) driving, just down the road from a friend's house in Atlanta.
JB welding a crack in the radiator and road trip back to Nashville, top down with some beautiful fall weather. Front passenger wheel bearing was holding on for dear life, but made it home safely with all four wheels still attached.
Pulling drivetrain and full wiring harness on the RX7
Disassembly begins on the Triumph as well. Firewalls made of fiberboard make this part a breeze.
Nice! Factory hardtop too. Does the rotary engine have much torque? There is a bike engine swapped Spitfire on another forum and they kept the stock diff. due to the low torque of the engine.
Hey, we did a rotary Spitfire project in the long-ago times–like in the ’90s. A few updates can be found online.
In reply to NermalSnert (Forum Supporter) :
I'm kind of hoping that will be the case, since I don't plan on further modifying the rotary any time soon.
Been doing a lot of bench racing trying to come up with a line in the sand to draw for this initial pass at getting it roadworthy. The rear end and brake system need full rebuilds, and obviously a custom driveshaft for the swap. I'm weary to throw a ton of work and new parts at the stock set up, only to redo everything and go to a custom rear shortly after, but I also don't want to bite off too much and never get the project on the road.
Most research leads me to dead links or parts combos involving very difficult to source components in the current year and in the US, so open to any recommended reading or harebrained schemes that anyone has before I start throwing money at the current setup.
In reply to David S. Wallens :
I found that project shortly after acquiring these two platforms. Seems like there was a decent rotary spitfire community back then from some threads I've stumbled on.
No such thing as an original idea!
In reply to BigDaddyDeek :
Getting it on the road sounds like a good idea. A little mechanical empathy goes a long way and you can upgrade at your leisure.
You've probably seen this already:
http://auskellian.com/paul/links_files/performance_enhancements.htm
Yes, great resource for compiling some basic chassis tuning info and clearing up some of the parts interchangeability with the TR/GT models.
If I can get my hands on the parts, hoping to use some of the GT6 upgrades mentioned in there as a starting point for my suspension rebuilds.
You will want/need to do something for the rear suspension. Easy button is to convert to a Triumph GT6 rotoflex style rear suspension and use a subaru R160 rear and custom CV axles. That can all be a bolt in kit, but it will cost you. Or you can build something custom, but I can tell you the RX7 rear suspension is about 8 inches too wide and there is not much room to mount it. Lots of cutting to try to fit alternative suspensions like a Miata, etc....
In reply to dherr (Forum Supporter) :
RX7 rear trailing arm suspension would be too difficult to narrow and adapt to the frame setup, so I agree that's a no go.
GT6 rotoflex would be the easiest option relative and keep the Triumph spirit. But the cost of a full setup has me thinking some real scope creep thoughts (at least cost piecing it together from what I can find currently listed on Ebay/forums, that's before I get into axle and hub converisons).
The current prevailing thought is a custom Miata rear adaptation. Initial measurements look promising, cutting out the stock rear upright crossmember seems like it would give me enough room to CAD a laser cut tab-and-slot assembly that could interface with the stock rails and pickup control arm and diff mounting. This route would surely delay getting the car on the road compared to Triumph-lego approach, but the availability of cheap roadworthy Miata rear subframe assemblies and getting a permanent solution the first time around makes me consider taking the plunge.
PS Dherr, your build thread has been great reading, appreciate you popping in here. If you've got a line on anyone who may have some cheaper GT6 takeoff parts I would love to make some connections. I've put a few feelers out there, but I haven't been able to get plugged into the LBC forum parts network that seems to hold all these hard to procure pieces.
Is there a huge downside to simply restoring the Spitfire rear suspension? Other than it will handle like a stock Spitfire...but maybe that would still be fun and relatively cheap for now.
In reply to maschinenbau :
That was my original plan, to rock the swing axle and stock diff until I found a bigger problem, and that's probably what I should still do. I started down this rabbit hole because of how crusty the current rear end is, with the car being off the road so long I'd probably rebuild the stock axles and upright assemblies before I dared driving it, and I still need a custom drivesahft made up to whatever diff I'm using. I'd like to avoid having to spend the same money twice, which lead me to consider going straight for Rotoflex conversion, which lead me to consider going straight for a custom setup.
I've still got a few boxes of parts left to pickup from the previous holder of the Spit which have some brake and suspension rebuild components, so I'm committing to keep busy on other tasks in the meantime until I can assess what I already have there. If I can bring down the cost of rebuilding the current setup closer to just a custom driveshaft and some cans of heavy rust penetrant, then I'll probably run with what I've got for an initial pass. There's still plenty of time while I figure out the rest of the swap, hard to keep a lid on the impatience when the prospect of a never ending project is on the table :)
This should be a fun project to follow. I do like some RoSpit.
My rotary spitfire uses a modified rear frame section holding a Mazda LSD diff out of an FC IIRC, built arms, Miata uprights, brakes and hubs, and shortened axle shafts. The shocks are R1 motorcycle rear shocks with heavier springs.
Bad picture but it's all I have.
The front suspension is similar. Modified Spitfire arms with Miata ball joints, uprights, and brakes. It also rides on R1 rear shocks. I don't have any good pictures of the front suspension.
It's a hoot. I have considered buying a street legal body and moving all the parts over but I already have too many projects.
I'm looking forward to which direction you go.
BigDaddyDeek said:
In reply to David S. Wallens :
Seems like there was a decent rotary spitfire community back then from some threads I've stumbled on.
No such thing as an original idea!
Not surprised. Seems like it would basically be a Cosmo.
