this is from an 89 with about 110k on it. so I pulled my motor from a bad coolant seal and began to take everything apart and clean the sonovabitch and to my surprise the front rotor appears to be scalloped but very lightly. I've held a scalloped rotor before so this confused me.

the texture looks too uniform to not be machine done, it feels like the bathtub texture on the rotor, but all over it.

here are some shots, they are a bit blurry but you can kinda see the one on the left is the textured one and the one on the right is the smooth one. neither of the rotors are completely cleaned (yet) and neither show any signs of damage.






I need a better camera or a steadier hand the flash kept ******* up the shots so yeah lol.


this gave me the hunch that his has been taken apart before, that and the giant F on the front rotor housing.

is this scalloped lightly or what?

 

I dunno, if someone actually tried to scallop them. That is the most baby scallop ever. Probably not even worth it. It would actually make me skeptical of the rotor.

Edit: pfft, I was about to show you a real scalloped rotor. But now I remember which set of scalloped rotors you saw!

 

that is not a scalloped rotor. A scalloped rotor gets some material removed from the side that closes and opens up the intake ports(close to the side seal area right at the edge of the rotor)in order to open up the intake earlier like on a bridgeported application but without cutting the eyebrowns on the plates and the motor will run and idle like a bridge if the cuts on the rotors are well cutted.

 

The scallop/bevel varies in size. My set was cut very deep into the face of the rotor, but the scallops on the Renesis rotors are quite small.

 

The rotor on the left if from a S5, Mazda used a machining process to make those. The one one the right is a S4, those were casted. I'm surprised the engine ran ok considering they are different compression ratios.

 

exactly my thought and yeah I had seen yours

that makes sense because the rotors have (1 3 5) (2 4 6) labeled on both of them. shouldnt there be a (7 9 11) and a (8 10 12) on the other rotor? it ran fine for a month or two after I got it...until it overheated then I knew it was downhill from there so I proceeded to beat the snot out of it for the remainder of its life.
it still ran great (when it didnt flood on startup) when I pulled it but it was a little down on power...

I didnt notice any excessive vibration because I have solid motor and trans mounts

I wanna slap the person who rebuilt this motor, not to mention not using 3rd gen corner seal springs...

this is the first S5 i've torn down

now I need to find a second rotor because I do not want to use s4 rotors.



to the max

 

Those look like two S5 rotors to me.

I think the carbon left in the pocket is confusing and makes it look like a non machined surface. Look closely at the third pic and notice the spots that are shiny clean.

You would know if it was 1 S4 and 1 S5 rotor, it would shake horribly. I mean horribly. I mean you would have gone WTF ZOMG!!!!

Regarding the 1-12 stamps, I have no clue but the Mazda seal case has two 1-6 designations. http://www.pineappleracing.com/mazdasealcase.aspx

 

okay well Im an idiot but it still looks funny. and if there was an s5 and s4 rotor at high rpm that much imbalance would likely snap the eccentric shaft.

and I guess I was wrong about the seal case.

I'll have them cleaned next wed and maybe take a better photo but the two surfaces are distinctly different.

 

no, rotors are interchangable front and rear...

ive seen a few s5+ rotors machined like that, even NEW ones its like the bit was a little dull that day or something.

 

can anyone help confirm if I have an S4 and an S5 rotor or both S5 rotors before I go out and buy an S5 rotor like an idiot?

 

Both rotors look to be S5

Put them on the scale and get the weight..

 

yeah that was what I was thinking of doing, I have access to a nice scale in the same place where I have access to a nice hot parts washer too but I cant get there till wed...

clean parts soon to come

 

the bathtubs still look different tho.

 

^ Look closer.