How hard is it to rebuild a Mazda RX-7 FD engine yourself?

Rebuilding a Mazda RX-7 engine yourself is a Moderate to Hard task. While the physical teardown and assembly is considered "really not that hard," the precision required means that any mistakes can quickly become an expensive lesson, especially since you won't have a warranty to fall back on ¹.

If you are considering tackling the engine in your FD, here is the best way to evaluate the job:

1. Review the Factory Service Manual (FSM): Get a copy of the FSM and read through the engine overhaul section. Seeing the required procedures, tolerances, and specialized tools is the best way to judge if it matches your current abilities ¹.
2. Watch Walkthroughs: Search for Aaron Cake's rotary rebuild videos on YouTube to get a visual feel for what the process entails before you commit ¹.
3. Price Out the Options: You will absolutely save on labor by doing it yourself, but you should price out seals, rebuild kits, and any potential machining to understand your budget constraints. Compare that material cost against the cost of sending the engine off to a professional to weigh your options accurately ¹.

Ultimately, there is no shame in having it built for you if you decide the risk outweighs the labor savings. Read through the manual first, and if you feel confident in your mechanical skills, it is a highly rewarding project.