Just put on EBC pads & my rotors turned purple!!
07-28-2003, 08:36 AM
#3
Re: Just put on EBC pads & my rotors turned purple!! It depends....
If cast iron is heated excessively (somwhere aro0und 1300 degrees or so) a transformation can take place. The grain structure of the iron can change into something called "cementite". The thermal properties of cementite are somewhat different than that of iron. Cementite is slightly more resistant to wear and also handles heat a little bit differently. Many tests for cememtite formation require "destructive" testing (the part is destroyed), there are also methods that are "non-destructive" but I'm not sure where you'd find a person who has access to the correct test equipment....who will also help you. I'd inspect the rotor for hairline cracking, some small surface cracks are "normal" after track use (or a thermal cycle such as yours) and are not a huge problem. If there are any radial cracks that run clear out to the edge of the rotor (most of it's width), I'd discard the rotors and replace them with a new set. If there are no cracks, the pedal dosen't vibrate (warped rotor) and the car seems to stop normally, my opinion is that they would be ok to use.
Just my thoughts,
Good luck!
If cast iron is heated excessively (somwhere aro0und 1300 degrees or so) a transformation can take place. The grain structure of the iron can change into something called "cementite". The thermal properties of cementite are somewhat different than that of iron. Cementite is slightly more resistant to wear and also handles heat a little bit differently. Many tests for cememtite formation require "destructive" testing (the part is destroyed), there are also methods that are "non-destructive" but I'm not sure where you'd find a person who has access to the correct test equipment....who will also help you. I'd inspect the rotor for hairline cracking, some small surface cracks are "normal" after track use (or a thermal cycle such as yours) and are not a huge problem. If there are any radial cracks that run clear out to the edge of the rotor (most of it's width), I'd discard the rotors and replace them with a new set. If there are no cracks, the pedal dosen't vibrate (warped rotor) and the car seems to stop normally, my opinion is that they would be ok to use.
Just my thoughts,
Good luck!
