https://www.rotarycompressiontester.com

 

I assume these work pretty well. Its been awhile since I have had any FD issues or time to dedicate to the FD. I remember the twisted rotor ones were just coming out. Theses seem a little better though.

 

Look into it. Its more accurate than the mazda tester as it automatically compensates the results for altitude and different cranking rpm. No need to use the correction chart manually. It's the new standard for compression testing a rotary

 

^Get it, it's definitely worth the coin, I have one and love it.