Does anybody have anything else to add? There's several Japanese symbols and characters on these rotors that I cannot read. I wonder if the answers lie there in being able to spot a definitive marker to know "what kind of rotor I've got".



I have many more pictures at the link http://bdc.cyberosity.com/pictures/RotorIdentification/ I can post for reference' sake.



B

 

Some of us at one time or another may be forced to violate that rule just to get a motor in our personal car. For instance, I currently have an A and C weight rotor in my car.



I was told that I shouldn't worry about it, but I do.



Could some of you more experienced guys reply concerning some precautionary measures that I should take when I disassemble the motor? What should I be extra concerned about? E-shaft wear & tear, uneven or excessive bearing wear, etc?



Any info or elaboration on what BDC has said so far would be much appreciated.



Great thread.



TIA,

 

https://www.nopistons.com/forums/ind...howtopic=34787



someday i'll take pictures

 

Brian,



In the 2nd picture you posted, the katakana symbol next to the "B" means "TA".



If you have any others, take pics and I can read them or get my wife to read them if I don't know the symbol myself.

 

I think that a lot of people label them front/rear because of the bearings and not the rotors themselves. For instance, if you have an engine that messed up a coolant seal, and you don't want to change anything internal, you would label the front rotor so that it would correspond to the part of the e-shaft that it already wore down to.

 

The Japanese symbols are all katakana symbols, and you easily get a "katakana chart" to read all of them. They don't denote anything except for seal position. You'll see three of them per side to keep track of side seal position.







-Ted

 

the 12a rotors are front and rear, the chamber shape actually differs between them. the 13b rotors are all the same part number front and rear, except for the renisis; because of the cut on the side of the rotor (miter?)

 

pics!



70-73 12a rotor, note the dual side seals and huge apex slot







83-85 rotor, you can tell because its got the N in addition to the R or F,

i dont have any 74-82 rotors to photo







can you spot the difference in chamber shape? d'oh i just noticed its 2 rears! i'm fired!







12a vs 13b, the 13b rotor is an 86-88 na one. the 70-73 rotors are the same front and rear

 

70-73 12a, note the rounded part where it doesnt say mazda. these are the carbon seal engines







heres a 76-80 rotor housing also 12a, notice it now says mazda on it. it can be id'ed by the ribs on the top







comparison of exhaust ports, the 70-73 is the big one







heres an 81-85 housing, notice the eyebrows on the spark plug holes

 

I really like the look of '73 and older 12A housings. Works of art.