1980 Mazda RX-7 FB Engine Conversion?

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1980 Mazda RX-7 FB Engine Conversion?

Post by Zuez » Sun Jun 12, 2016 5:47 am

Hello, I'm new to this page and I'm hoping someone could lend me a hand. Recently I found a 1980 RX-7 FB/SA in really good condition, and by good condition I mean it has little to no rust. Just a bad interior and paint. Body is in good condition, engine still there with no leaks. Didn't get to start her up as the owner removed the wheel lock cylinder, but it looked like it could run without much hassle, and the owner is selling it for 700. Now this seems like a really good deal and all but there's one problem; I don't want the 12A that's in it nor do I want to swap a 13B into it. I was hoping to find a suitable 4 cylinder swap for the car, maybe a miata engine, but people say those are too heavy, or an SR20, but all the research I've done has led to hearing that its stupid and that I'm stupid for swapping out the rotary.

If I can't find a good swap then I'll just restore the car and sell it, but I want to be able to keep it for myself. Thing is, I want good mpg, don't really care much for power, just enough to still have fun with. I'm really hoping that I can find a swap or a solution to this because I really want the car for myself. Otherwise I'll just restore it, sell it and buy an FC to do an engine swap with or look for a BMW E30.

So I'll ask the question again; is there a good engine conversion for this car that would get me good mpg?


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Re: 1980 Mazda RX-7 FB Engine Conversion?

Post by DKWW2000 » Sun Jun 12, 2016 10:39 am

Hi & welcome to the Forum. With regards to your question, there are several Topics on Piston engine swaps, but those that have done them do not tend keep the cars for long, & once changed it is difficult to go back to original.
In my opinion the whole essence of the car is the Rotary engine, compact lightweight sporty & if driven carefully a reasonable MPG can be achieved. If you work out the cost of the Swap in relation to better MPG I would wager it would not cover 5 years + motoring :o The weight of a piston engine also changes the handling of the car as it is roughly a 49/51% balance.
I would suggest stick with the Rotary first, as you will probably get addicted (as most of us do) to the characteristics of these unique rare little cars.
Regards Pete
RX7 FB S3 - RX7 FC TII Vert
Rotaries Previously Owned:-
2 x NSU Ro 80s - 2 x S2 RX7s - Suzuki RE 5 - DKW(Hercules) W2000 - Norton (Krauser) Commander

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Re: 1980 Mazda RX-7 FB Engine Conversion?

Post by ian65 » Sun Jun 12, 2016 11:20 am

Welcome to the forum h:

These cars are a 40 year old design with old technology now and there are much better options out there if you want a piston engined car.
The thing that makes FB RX7's so much fun to drive is the complete package but it relies heavily on the rotary engine... remove that and it's lost it's soul.
Sure, you can put a Miata engine into the RX7 but it will take away the car's main positive feature, you will never see any money again that you spend doing the swap and when it's all complete the car will have become practically worthless.
Back in the day, people used to drop Ford engines into these cars if the rotary engine died.....there were quite a few of these conversions about.... where are they now? All scrapped because they had ruined the car and no one wanted them.

My advice is buy the RX7, recommision it then sell it on and make a few bucks and buy a Miata.
You'll then have a nice, well engineered piston engined car that gives good mpg and the RX7 will live to fight another day.
1986 Series 3 13B Turbo II
1992 Peugeot 205 1.9 GTI
1975 Honda SL125 Street Scrambler

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Re: 1980 Mazda RX-7 FB Engine Conversion?

Post by Zuez » Sun Jun 12, 2016 4:23 pm

Wow thank you all for the replies and thanks for the welcome. After thinking about it, I guess I will restore the RX-7 seeing as its the best way to go. Its in good condition for its age and if swapping the engine only ruins the car then I'll keep the engine along with the cars soul. It also saves me the headaches and my wallet :lol:

Again thanks for the replies. I'll be sure to start a thread of the restoration sometime after I purchase the car.

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