I am in the middle of doing a TII conversion on my Na Rx7. and while the motor is out i am having it rebuilt and having a stage III street port done on it. i am also doing a T66 turbo upgrade and thats all i can tell you without letting the cat out of the bag. i am in the middle of a debate that has me baffeled. I need to decide if i wanna go with 2mm cryo-hardened seals or 3mm cryo-hardened seals. or should i go for the aviation seals. i am plannin on pushing 15-20 psi.



As far as the seals go i am clueless. i have heard that the 3mm seals dont seal as well as the 2mm seals, and the 3mm arnt good for daily drivng.



Any and all advice or comments welcome. i would like to hear what jim has to say.



TurboSmoke

go for the 2mm seals, they work better

Ive always been told and read that 2mm is better as well. Keep it factory with the apex seals (meaning 2mm https://www.nopistons.com/forums/pub...IR ).



-Marc

apparently the aviation seal can withstand 3 pings. i'd go with them

I also read on rx7club people were having problems with premature wear with the RA seals.



http://www.rx7club.com/showthread.php?s=&t...rotary+aviation

so can the stock ones, just depends on when you ping

So are you going to cryo everything else in the motor?

I had a bad knock in mine with the 2mm seals drove it several times that way before I figured it out, it didn't kill them.



As far as the cryo treating I am just not sold on it yet, only time will tell.

Damn, someone elso cyroing thier engine.

i have 3 mm seals on mine, not sure of the material, just know it added to the cost of my rebuild two summers ago. since then, i've put 2 hard years on my car, complete with drag racing and some autox runs. they work fine, and i haven't had any complaints. i make good power, and the car runs strong and reliably.

i am not going to cryo the whole motor, i am just going with the cryo hardened seals. i am still debating on if i should go with 2mm or 3mm. my mechanic thinks very highly of the 3mm seals and i value his opinion. i also value the people who have had to deal with this kind of stuff before. its just a agravating process.



TurboSmoke

A fairly good friend of mine owns cryo shop and I have seen somethings that impress me. What I would worry about with just cryoing the apex seals is that is going to be harder to break in and it is going to be very hard on the rotor housings.



Only way I would cryo an apex seal is if I was going to cryo the rotor housings.



FWIW cryo treating works awesome on parts that wear. I don't know if it will help much with keeping a seal from breaking. But if you do the seals and rotor housings it will help greatly on long term wear.

Same here.