Preserving Coolant Seals on Rotary Engines (1974-2012)
The 13B and Renesis rotary engines used in the Mazda RX-7 FB, FC, FD, and RX-8 all share a common issue that encourages coolant seal failures. This means it's not unusual for rotary engines to start consuming coolant; sometimes just out of the blue, but more commonly after being overheated. At our shop, we often check the tension bolts while replacing clutches and transmissions, and nearly all of them have lost some holding force. This is further evidenced by oil seepage and wetness around the base of the engine and just above the oil pan.
We theorized that repeated heat cycles of dissimilar metals (each having different rates of expansion, as in the case of aluminum and cast iron held together with steel bolts), internal stress loads from normal use (or heavy use during street driving / track racing), together with combustion-generated vibrations causing minute movements between the segments, all results in a gradual relaxation of tension--the force holding the engine together. Then as a hot engine cools, even more force is lost... eventually allowing coolant to leak by the seal into the combustion chamber.
This issue is most common in any rotary engine being repeatedly overheated, engines with a higher power output, and all Series 6-8 / Renesis engine assemblies 10+ years old regardless of mileage. Historically, the only solution available was to rebuild the engine and replace all the coolant seals, typically costing thousands of dollars.
That's why for years, we've experimented with a few different methods in an effort to more easily resolve this chronic flaw and extend the usable lifespan of the engines still running. The good news is that after applying our solution to over 100 rotary-powered vehicles presenting coolant consumption-related symptoms (such as cold start misfire and white exhaust smoke), 90% of them completely resolved and provided many more years of driving enjoyment.
Introducing our CPR Kit (Coolant-seal Preserve / Revamp Kit); a product to help prevent coolant seal failures as well as correct early stages of coolant consumption, typically evidenced by the symptoms mentioned above. The CPR Kit can restore the integrity to your rotary engine holding it tightly together again like new.
The kit includes everything needed to help prevent coolant seal failures as well as correct early stages of coolant consumption: vibration dampener / positioners, sealing washers, low-friction thread lubricant, sequence template, SPK, system treatment, and our step-by-step installation guide. Installing the CPR Kit requires removing the transmission, clutch, and flywheel. This is also an ideal time to replace worn parts and / or add upgrades, like a new flywheel, clutch kit, and short shifter, as doing so will save additional labor down the road.
Product no longer available for purchase. This article has been uploaded for posterity.