i think hes refering to chamfing, or maybe it is spelled champhering. whatever. its pronounced the same. meaning to bevel the edges of the rotor like the rx8 rotors.



this drops weight off the rotor significantly, and gives the effect of earlier and later port timing.

 

oh yep got ya,thats the trubble with automotive, to many bloody terms which mean the same thing, i would have called it beveling but never mind.

 

I was under the impression that chamfering was machining the sides/corners to prevent the rotors from hitting the side housings when the eccentric shaft flexes.



Just like why you open up the bearing tolerances. You can't prevent it from happening so you have to accomodate it.

 

if you buy NEW rotors they have this done already. mazda even sells em in a kit with all the seals and housings, they call it a reman engine, but its cheaper than buying seperate