Project FD RX7 Restomod: Part 12 – Rotor Lightening, WPC and CTP Cryo Treatment

13B Rotary RX-7 Apex Seals CTP Cryogenics and WPC TreatmentPiston rings are one of the best components of a piston engine to WPC Treat to reduce friction.  For our rotary engine, that means WPC and CTP Cryogenically treating our apex seals, corner seals, and our rotors.  We treat the rotors themselves to reduce the friction and binding between the apex/corner/side seals and the rotor itself.  This allows the apex seals to move freely in and out of the rotor tip to follow the trichoid shape of the rotor housing.

13B Rotary FD RX-7 side seals WPC Treatment CTP Cryogenically treatedSide seals are just as important to WPC and Cryogenically treat as the apex seals.

Atkins Rotary solid corner seals WPC Treated 13B RX7We are using the Atkins Rotary solid corner seals in our build.  These seals are stronger and will not crack at power and durability levels that break factory seals.  The Atkins solid seals also features a ‘dish’ to reduce surface area contact and friction with the side irons.  After WPC Treatment, these corner seals will greatly cut down the friction and wear on the side irons.

13B REW Rotary FD RX-7 Stationery Gear WPC Treatment CTP CryogenicsWe also WPC and CTP Cryogenically treated the stationary gears of our engine.

13B REW FD RX-7 e-shaft, apex seals, stationary gears WPC Treated CTP Cryogenics treatedWith all of our internals treated, they were ready to be assembled.

13B REW FD RX-7 WPC Treated Rotor CTP Cryogenically TreatedNow that our rotors were lightened by an impressive 0.638lbs each, cryogenically treated by CTP Cryogenics to uniform the crystalline structure of the metal to improve durability, and WPC treated to reduce friction and wear, we were ready to send them off to Mazdatrix to be balanced.  Stay tuned for the next segment where we go further into our engine build.








        1. The video with Rob was around Part 9, then a standalone ECU was put in the car with a datalogger to get some baseline data on a relatively stock engine. Unfortunately the heater hose that was used as a fuel line by the shop who installed this engine was loose and caught the engine on fire. So between Part 11 and Part 12 is over a year of work upgrading the suspension and drivetrain that will be rolled out here shortly.

  1. Billy, this series is amazing! I keep looking at importing a later JDM model RX7 and part of that research is reading this FD series over and over again. I am scared at the bill for buying and building a rotary, but this series will show everyone how to do it right!

    1. Thanks for the feedback! Just do some safety and reliability-related modifications and enjoy the car! We will be doing articles on those items like the fuel and cooling systems which are crucial for rotaries – also to prevent fires like what happened to my car.

    1. That would make no difference in anything. except for possibly reducing heat transfer out of the rotor which is not good.

    2. I believe Racing Beat went a step further and removed material and weight from inside the rotor. FWIW, Mazdatrix does not do this and removes weight from the outer side face of the rotor like most shops do. I’m sure removing material from inside the rotor has its merits/advantages; possibly driven by rulebooks in racing.

  2. Following from Japan.
    Its great to see a serious build where the focus is on building a highly efficient rx7. I wish we had WPC in NZ… im taking my rotary parts to Japan to get them done.

    Thank you Mike and Billy.

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