13B Family

Cross-section of a 13B engine
Cross-section of a 13B engine – photo by Softeis

13B Family

This page is still under construction, and may not have complete information.

All Engines


  • Apex seals, corner seals, and side seals – carbon deposits will eventually wear out the seals and cause the engine to lose compression. Rotaries should go to the redline at least once per drive to blow out carbon deposits. A compression test at a Mazda dealership or rotary specialist is a necessity as part of a PPI. This cannot be performed like a normal compression test, as the rotary engine has a variable compression ratio unlike a regular internal combustion engine.
  • The cooling system should be closely monitored, as overheating can warp the rotary housing and cause the engine to lose compression. Common upgrades include bigger radiators and lower-temperature thermostats.
  • Engine repairs can generally only be performed at rotary specialist shops (which are few and far between) and Mazda dealerships.



  • Mazda RX-7 (FC)

13B-MSP Renesis

Additional Problems

A typical engine will generally only last 50-70k miles before it loses compression and requires rebuild. Frequent oil changes, regular seafoam treatments, 2-stroke premix, and lots of high revs can prolong it up to 100k miles, but this is unusual. MY2009+ vehicles’ engines seem to live longer thanks to the addition of a third oil injector, but they will still require a rebuild much earlier than the average internal combustion engine.

Worn apex seals can damage housings and rotors (among other things), so it is not unusual to require these items as part of a rebuild – especially if the seals are allowed to wear to the point where the vehicle no longer starts even when cold.

A reputable independent shop can rebuild the engine for as little as $1600, depending on what is required for a specific engine. Mazda also directly sells remanufactured engines for $3000.

Certain Vehicles

  • MY04-08: The ignition coils in these vehicles allegedly require replacement every 30k miles. There are kits that allow you to use ignition coils from a number of GM LS engines which last longer.




  • Mazda RX-7 GSL-SE (FB)



  • Mazda RX-7 (FD)



  • Mazda B-Series Rotary-Engined Pickup (Gen 2)
  • Mazda Cosmo (Series CD)
  • Mazda RX-4 (LA2)