Cracked apex seal, what's the cause?
 

engine is pulled apart and everything is new (yes everything), one alex seal has a tiny crack at the edge. Running 13psi on octane 91. I was told by one person that it was due to having super cold plugs (11) and an ignition employer, another one is telling me that it's the tune. Car has a fcon vpro for emanage, T04S turbine

cracked seal = detonation/preignition, so its the fuel/tune

My thoughts on why seals brake, (but especially on harder stock seals).
Barry

https://www.rx7club.com/showthread.p...t=barry+bordes

I'm having a hard time believing it's the tune, yes I know that it's the most common culprit of a broken seal, but this car has been tuned by an HKS dealer in Japan and ran 20psi on Japanese gas when it was used for drag racing. I also know people using petro 91 without problems here in Canada... Would driving the car with a really hardcore silencer create backpressure and cause this? I remember when I got the car It wouldn't even make 0 bar until I took out the silencer..

Can I get anymore input?

Wouldn't the combination of type 11 plugs, one iffy coil and crusty ignition wires cause ignition to be out of wack?

Would having a silencer that doesn't let you spool AT ALL contribute?

The gas is the problem.

91 was most likely not enough for the tune.