CaseyJones955

Good afternoon all.

I have recently picked up a 79 MG Midget and I love it, in spite of its anemic, crude engine and clunky transmission geared for a roller skating rink rather than open roadway (which I have a lot of around here).

After some consideration I have decided to install a rotary engine w/ a matching 5 speed trans. Size, weight, output are the determining factors, but its unique and has character, hence it would be more fitting of such an oddball car like this one.

The car will not be a race car, only a daily driver and for road trips. The engine will NOT be modified. I figure anything on the other side of 100 hp will make this thing plenty fast for its intended purpose. I am hoping for some experienced rotary users to chime in and enlighten me.

1. Years/model specific info desirable (or not desirable) I should look for in a donor car, I will be using the engine/5speed trans as a unit. Carb is preferred for simplicity unless keeping injection is pretty simple (like the stand alone ford EFI systems).

2. I understand some rotary engines are prone to overheating and catastrophic case failure, If true, which years/engines to I want to stay clear of. Reliability is priority.

3. When assessing the suitability of a donor car, what signs/symptoms should I look for to determine an engine w/some life left in it or something that needs repair?

Sorry for the long post but getting this info from a bunch of Ford and BMW nuts is nothing more than subjective Mazda bashing at best. Hoping for some serious experience and thanks very much for enduring the long post. Any info on any of these Q will be greatly helpful in the completion of this project.

Thanks,

Sincerely, Tony

Jeff20B

iTrader: (13)

Welcome.

You should start by using the search feature of this forum. I just tried it and found an old post of mine detailing some history and recent work I did on my MG.

https://www.rx7club.com/forum/showthread.php?t=515846

CaseyJones955

That is a great outline, I saw these pics somewhere else on the net also. Very cool job. So the 13B is the engine to use?

I have been given so much conflicting information recently over the best and worst engines/years and how to pick one out w/some life still in it. I figure intsalling it will be easier than finding/buying a donor car.

Its almost as if there is a state law here in SD that prohibits the sale or use of anything outside the ordinary. I havnt seen a single RX-7 on the road or in a yard since I have started looking for an engine. Its like Ill be lucky to find ANY donor car much less being picky over year/engine model.

Thanks. Tony

Jeff20B

iTrader: (13)

Since you are just starting out, I'd say a 12A is the best choice as carbed 13Bs are ridiculously hard to come by. Don't try to use a Ford system on your rotary. I'd use stock EFI over Ford. *shudder*

CaseyJones955

I slapped a 94 5.0 EFI from a wrecked Cobra into a 78 Fairmont and the EFI wiring harness is pretty much stand alone. For this reason retrofitting the EFI was a straight forward operation.

If I couldnt use the Mazda EFI I would be satisfied w/the carb. I am not yet aware if retaining the Mazda EFI system is that simple or not.

Thanks for the info on the 12a, I am seeing a few on Ebay but still nothing local, I hear buying a used rotary, especially sight unseen, is a roll of the dice at best.

Is the 12a smaller in size/weight than the 13b?

I would also still love to hear how to tell if its tired or not w/o a teardown.

Thanks for the response, It is helpful as I know NOTHING about rotary engines yet.

Tony

Jeff20B

iTrader: (13)

I built a 12A this spring that would be perfect for your MG. It runs well in a 1st gen RX-7. All it needs is a carb rebuild.

You can see and read about the 12A here.
https://www.rx7club.com/forum/showthread.php?t=539579

I could build you an identical engine if you're interested. I also have trannies.

We would need to take this conversation off-board to keep within the rules here. Send me a PM (private message) and we can talk further.