ok is kind of hard to explain. but here we go. my S5 n/a engine blew a apex seal and it damage the rotor, im planning to buy a used rotor but my friend said that they have to match the letter with the other rotor. what he means about matching the letter and were that letter located on the rotor? thanks

eddie

 

http://www.rebuildingrotaryengines.c...ight_balancing

 

Flip the rotor so the bearing TAB is facing up and at 12 o'clock. Look on the face of the rotor @ 2 o'clock. There is the letter. Ignore all of the japanese characters. The numbers are used when loading seals into the rotor, not for balancing.

You want to buy a rotor that is the same as the one you have. If you have a C, buy a C. You can go up one letter or down one letter so B, C, D could be used with a C. But not an A or E. Don't skip a letter - I think that video says you can skip a letter.

Most used rotors have some sort of problem and are not usable. Especially if you can't see it first in person before buying. There's an amazing number of people selling used ROTARY JUNK that they'll say "ran fine" or I don't know.

Good luck. Oh, Mazda has some 3 piece 2mm apex seals that popped up in inventory somehow lately. If you get some, exchange them for two piece.

 

thanks guys

 

But what if I changed both Rotors new from Mazda?

 

somehow magically every new rotor is a C weight.

 

So there's no problem if I buy 2 new matched Rotors?
If my old Rotors were A and I replaced them with new C Rotors, is it okay?

Nevertheless i was also told that Mazda has stopped the letter system on the Rotors, they are all from now on matched. So I guess it's only C.

 

so i went to look for the part in the service manual that explains this letter balancing thing, and the NEWEST english manual to explain it is the 1974 Rx4 manual, if you look in anything newer, this section isn't there, but there are still letters on the rotors.

so the pertinent info, from the 1974 Rx4 service manual "if it becomes necessary to replace a rotor, use the rotor marked C in all cases"

if we look in the 1974 Rx4 parts book, it says rotor "C"...

so why do the rotors still have the letter stamp but its not in the manual? simple, if every replacement is a C, and its ok to use a C with any other letter combo, then it doesn't need to be in the book.

if you're using used parts, you're on your own anyways

 

I see, so there's no problem to get both new Rotors with the letter C too, even if my old Rotors were A or B or D or E, because in my case I need to change both rotors not 1, it's no problem to replace them as long as you get the new ones with matched letters, unless if you wanna replace 1 rotor, then you should match the used or new replacement rotor with your old rotor. Ummm Right? (^｡^)

But what about What DriveFast7 said? You cannot skip a letter twice, meaning if you're B you can go one up which is C or one down which is A, but I can't jump up or down twice????

 

And that's why one of the guys told me that Mazda is no longer following the lettering system on the Rotors, they're all now sold with the letter C, which means C will work with all other letters?

 

the pertinent info, from the 1974 Rx4 service manual "if it becomes necessary to replace a rotor, use the rotor marked C in all cases"

ALL new rotors are C, so you can ALWAYS buy a new rotor, or two

 

fairly sure the rule is 2 letters, which is why mazda settled on a C weight standard, which can be used with all others BUT for the best balance the letters should match.

 

Great... Thanks a lot guys (^O^)