Yeah, that thing you though was an "E" is actually a japanese symbol/letter/something.

 

Stupid Question ---------> How do you get them balanced? Just weigh them or what?

 

send them to a balancer...

 

There is with-in spec and there is dead on spec. Dead on is best, but hard to obtain.

There are shops that have these custom built shafts/scales to make sure that the assembly components are as close to 'dead on' as possible.

The take material out of inocuous places on the rotors/e-shaft/flywheel/etc in order to get them closer to balance.

It makes a huge difference in the way the motor runs, and makes a great difference in high rpm

 

So if I were to rebuild my motor I should do it? Motor has 150k miles. Using all same parts... Hopefully (except for the seals and stuff)

 

rotors look great!

 

it will make your motor more reliable, and run smoother
Its not neccisary, obviously is your motor ran well for 150k, but if you plan on keeping your car for a long time, it is def worth it.

 

Alright Thanks for your help.

 

they are sooo clean you can see the lines in the one rotor and there is non in the otherin the picture. By the way why do they have the lines?

 

Yep, each side seal groove has a Katakana symbol from one of their phoenetic alphabets (letter) stamped on the side. The "E" is actally "Yo" symbol.

On the assembly line they can just grab a "Yo" sized sideseal and plop it into the groove without grinding and get the clearance within Mazda spec.

Since the stamping is always closer to one side of the side seal I always put the apex seal and corner seal over there in the same envelope when keeping track of seals.

When using new seals or used seals in different locations you can use the Katakana stampings to your advantage as well. Keeps you from sticking the seal in every groove trying to find if it is too long or short.



These are written w/ a little brush flair font but you should be able to match the stampings.