We have an MG Midget that we have decided to swap a rotary into. The ultimate goal is getting a little better than 200hp. Since I'm new to rotaries, please feel free to educate me. Would we be better off starting with a 12a or 13b. Our budget is small. We plan to drive her on the street regularly, so reliability is paramount. Thanks, Jeff

 

13B.

It isn't straightforward to make 200HP from a NA 13B. On the cheap end you can get an intake manifold to mount up a Weber and with a nice exhaust, you should be close. But you will sacrifice all of the advantages of EFI, end up with less of a midrange and have to deal with carb tuning.

A little more expensive would be to set it up with a proper EFI system. You should be able to hit 200HP after some tuning and maintain all the drivability.

Or, just use a 13B turbo. Might be an issue fitting the plumbing for it though.

 

Thanks, Yep, that kind of mirrors what I've been reading. The compact size of the rotary and it's cool design is very appealing, but the cost of the parts is pretty scary. It must be a real shocker to buy a rebuild kit for close to a grand, and be able to put most of the parts in your pocket .

 

The cost of a rebuild "kit" can vary widely depending on what you require. The big ticket items are the oil o-ring carriers, which often don't nee to be replaced. If side seals spec out, it is more advisable to re-use the existing ones in a first rebuild as it means there won't be any mistakes made clearancing the new ones.

Sadly, rotary parts are low production compared to, say, rebuild kits for a Chevy 350. But you make up a lot of that money when you consider that in most cases there is no machining necessary during a rotary build.

 

So, for a 12a, what kind of kit would I need just to open it up to check it out? Any idea how much locally (London) for parts? Thanks

 

i would run a streetport 12A, but run a IDF weber or IDA weber carb.
manageable for the street, even if you run a real monster street port.
And you'll make good power, even over 200hp.
or a 13b streetport would be good.
just going to sacrifice quickness of revs, and maybe not going to be able to rev quite as hii.

 

You'll notice I am in London as well.

Far as I know, 12A gasket sets are still available from the dealer. Call up Probart Mazda, tell them I sent you, and ask. You can get the part number from the parts catalog here:
http://www.mazdaspeeddevelopment.com...s/rx7pubs.html

If they can't get it (I have not bought a 12A gasket set in a long time) then Atkins Rotary can ship you one. Tell Dan that I sent you when you order (not that I think it would matter or anything).

If you just want to open it up, a gasket set is all you need. But there is still a considerable amount of labor in just opening it up. Many hours of cleaning, mostly.

 

i hear that..cleaning up all the stuff is one big pain..rotor's especially, if you dont have a bench grinder with a wire wheel..

:AA:

 

I hope that was a joke, because a wire wheel on a bench grinder is NOT the way to clean a rotor. Maybe the cast face, but that's about it. Just a bit of a soak in carb cleaner will remove the carbon. Stubborn deposits can be removed with a Scotch Brite pad or razor blade.