12A Rotary Engine Builds | Having grown up around the 12A and doing what young men do with their cars, then turning to road racing as I got older, the proof of the 12A is undeniable. I have beat the hell out of these motors and they have stood tall as a reliable powerplant over the years.I'm talking about being a crew member of a racing team as a teenager (we raced an Rx2 in B sedan up until it became GT3). Driving them hard on the street for me was a weekly event. Then getting to watch a 12a with a full length exhaust exiting via a megaphone out the back, the 120db+ screaming sounds down those long straights was music while being painful for others.
Why does that matter? Because I broke them, blew them up and over-reved them a lot on the street. Then I had to rebuild them, ask questions and find out what others did to make them reliable. Every hear an apex seal break? Ever have the throttle stick wide open in-between shifts and have the motor hit at lease 14k and not break anything?
That was before we had the money for hardened stationary gears, proper lapping, the right tools for assemble, etc. We did what we had to so we could make hp and get on with our lives. I was a kid, doing dumb stuff from time to time, and it was a lot of fun. The teenager years were full of many stories and fun times spending weekends at road races, crewing and learning how to build proper race motors, transmissions, suspensions, etc.
As time moved forward, I was able to move up to higher quality vehicles of course and landing a low mileage '78 Mazda Rx3SP and off to college to tame many of my thoughts & desires and get a real career in the corporate world, and eventually get into racing. That is where the true skills and experience are put to the test.
Building 12A's is an art, taking it apart is just as important as when you get to put it back together, every piece has a place / function and understanding the ins and outs as well as why it takes a lot longer to prep the rotors, grind the side seals, match the apex seal grooves to the apex seals with proper clearances than it does to put the stack together.I was fortunate to make excellent connections with the guys that made serious power / reliability at the race track and learn from their experience. Listening skills lead to better outcomes when you are with the right company.
I still talk frequently with the pro race team engineers that build / race the rotary engine from those years, the stuff that gives us the edge isn't going to be always found or shared in the open.
We made very impressive power with the bridgeport 12A with a weber carb and MSD ignition (that still sits in the back of the shop and ran when I pulled it). With multiple finishes up front with the fast guys at the SCCA Runoffs and a motor that lasted 12 years as a full race prepped 12A, it is something to be proud of when rebuilding them for customers of today. Details matter.
Ask a lot of questions when talking to a builder of rotary engines, anyone can put one together. It is the prep, details and knowledge that leads to a motor that lasts years, makes solid power and fun to rev.
Topics: 12A, mazda rx7, Rotary Engine REbuild