80RX7LS

I have a 1980 Rx7 with the original 12A engine. This summer it's been running rough so I took it to my mechanic for a general "tune up". What we found wasn't pretty. Long story short the front combustion chamber had very low compression and was leaking coolant from the chamber when we removed the plugs to perform the test. The rear chamber however was giving a good compression reading. Plus the front bank plugs were very dirty while the rear were a nice golden brown. So after 41 years I believe it's time for a rebuild. Having read online that 12A parts were no longer available (specifically housings) I thought I was doomed. However after talking with a few rotary shops (my mechanic does not perform rotary rebuilds) they said the solution to the problem was to machine down 13B parts to 12A specs and they do it all the time. Two of the shops that impresses me the most were Atkins Rotary and Chips Motorsport, has any dealt with either of these two companies? Anyt comment on your experience would be appreciated.

Banzai

iTrader: (13)

Atkins has been around forever and I would't hesitate to trust them. Is the motor torn down and you're sure the housings need replacement? Could just need new seals. If you do need housings I'd post an a wanted add and maybe PM some longtime members to see what might be out there. Although scarce, (and expensive) 12A housings are still around.

Maxwedge

iTrader: (1)

Bonzai has MUCH more experience than me, but here's my amateur take on it...

12A housings are "around" but none are new. Buying used ones you are really gambling unless you are an expert with lots of rotary experience and a lot of parts laying around your shop.

If I wanted to rebuild my 12A I would love to buy new 12 A housings. Everything else in the motor is usually reusable. But if your surface / "chrome" is shot, um, get out your pocket book and cross your fingers.

What your shops are quoting to you is getting NEW Mazda '84-'85 GSL-SE 13B housings, which are still available new from Mazda (strangely) and milling them down 20mm so they fit exactly like the original 12A housings. They will replace the 12A housings perfectly and are the closest thing you will find to factory-original 12A housings.

If you are a 12A purist or are trying to do a 100% correct restoration, then this might not be right for you. But if you want a "new" 12A at a reasonable cost with original compression, performance and longevity then I feel it's your best option. And Atkins is a VERY reputable long-time rotary shop.

Also, this shop is close to you/us, and has a very good reputation with the FD guys I know (including my Brother's 8 second 1/4 mile car)....
Unique Precision Rotary | Rotatory Engine Repair Westminster

Banzai

iTrader: (13)

A thread earlier this year on shops that still do rebuilds:

https://www.rx7club.com/1st-gen-gene...021-a-1149576/

tommyeflight89

iTrader: (4)

In my opinion, the only place to go is Chips Motorsports. I would say best in the business. I had him rebuild my Streetport 12A. Not many shops out there, from what I have seen, have the equipment and skills he does.

For example, he has an in house surface grinder, to deck your irons perfectly flat and smooth, after which they are sent out for Nitriding.