new to this forum... but thinking of converting my 65 spit (http://mygaspedal.com/members/member.aspx?jwolff) to rotary power. Any advice as to where to start, best engine choice... mods needed to chassis and firewall. anyone local to northern VA (ashburn) that has been through this willing to mentor a bit? thanks

 

Hi and welcome,
I'm not converting a triumph, but I am converting another small british roadster-- namely, a '59 bugeye sprite. The engine I'm trying to cram into my little car is a JDM S5 13b turbo. I'm running into all kinds of fitment issues, primarily all related to just how friggin' wide the engine is when you add the turbo. It almost doubles the overall width of the engine... But then I knew it would be challenging when I started.

For your spitfire, I'd strongly recommend getting the back issues from Grassroots Motorsports magazine on their "Ro-Spit" project. They did exactly what your'e planning on doing, but they documented it all in a ~10-part magazine piece. Like most mag articles, it's a little short on specifics, but it does give a good overview. They also have some of the pieces online on their website.

As far as engine choices go, I'd suggest staying away from 12a engines and concentrating instead on the 13b variants... for just a little size and weight penalty, you can get a big improvement in power and availability. Plus, most 13bs are fuel injected, which IMHO is the only way to go.

Good luck...
-Bug

 

Thanks for the advice Bug! love the bugeye sprites.... going to be pretty insane I image when complete. Can I ask where you got the engine and gearbox?

 

Yes, the bugeye should be pretty crazy when I'm done. I going to keep the internals pretty much stock, but open up the exhaust and turn up the boost a little. I'm figuring on 250hp or so in a 1500 pound car. Good thing I have a roll cage, huh? lol.

Anyway, I got my engine, tranny, ECU, and harness from an importer out of Texas. The price was good and delivery fast, but some of the ancillary parts were damaged and/or missing. I wouldn't necessarily recommend that same importer again. FWIW, I found them through eBay. You can also find lots of stuff here in the classifieds section.

Cheers,
-Bug

 

Welcome to the forum.

I hope you can get the info you need.

Let me start by saying the 12A is a good choice because it is not complicated like the EFI 13B engines. I'd recommend a good 12A and 1st gen RX-7 tranny with a light steel or aluminum flywheel and a stock disc and pressure plate. You won't need anything that grips harder than stock because the car is so small and light.

When I had a stock flywheel in my MG Midget, I could do a burn out at 2k RPM and 2nd gear scoots were too easy. Then I switched to a light steel flywheel and the improvement in driveability was very noticeable. The previous owner also used a stock flywheel and actually destroyed several stock rearends. Since I don't want to upgrade this latest rearend to something stronger any time soon, I'll stick with the light aftermarket flywheel. The diff gearing is 3.7 so I felt the light steel was more appropriate than aluminum, plus it was a little cheaper. Still using the stock 215mm disc and pressure plate from the stock 30 pound flywheel (it's more than enough). The next upgrade will be to swap in an FC master and slave because the current MG master is too small and I walk funny for a couple days after driving the MG. The FC master cylinder is similar in shape and only a couple mods are needed to make it fit. The greater mechanical advantage will be perfect for the Mazda pressure plate. I'd think your car would be somewhat similar but I could be wrong.

Be sure to check out Eric Tischer's web page. I don't agree with some of his mods, but his car did run in the end. Look for the shifter mod. It moves the 1st gen shifter about 4" forward and fits the MG better. Your car may not need this. I got lucky and had an old style 4 speed from a REPU available which barely fits. I have access to a '79 4 speed which already has the shifter in the forward location, which you may want to consider for your car.

Check out this thread from last year detailing my MG Midget project. Maybe it will help you in some way. https://www.rx7club.com/forum/showthread.php?t=515846

 

Thanks for the links and advice... I'm looking to definitely go with a 5-speed gearbox, do you recommend 1st generation ones and will 1st gen mate up with later engines (yeah, this is all very new to me)

 

Yeah, 1st generation trannies are fine and will fit better than my earlier ribcase REPU tranny. They shift faster too. You will just need to move the shifter forward I suspect.

'74-'92 NA trannies are all compatible with '74-'92 NA engines plus the 12A turbo. The '87-'92 turbo II trannies are not compatible unless you know which flywheel, disc, pressure plate and starter to use. Also the turbo starter is further out and harder to fit in other vehicles. Stick with the NA trannies.

I won't necessarily need a 5 speed in my MG because of its 3.7 rearend.