I just recieved two new rotors from M-comp, and to my surprise there was a slight shoulder on the rotor sides where it appears Mazda now mills the rotors down by ~.002" to reduce the width. I've never seen this on any of the original rotors I've inspected.

This is interesting to me because I had planned on having the rotors milled down ~.004" on each side to increase the clearance, so now I'm tempted to just have the milling start at that shoulder vs: all the way at the outter oil control ring journal.

Anyhow, just wanted to pass on my findings. Any input is welcome.
Eric.

 

pics?

 

Pic






Whew, that was tough! You can see the ridge in these pics.

 

pic

 

Dial-up ownz you!

 

Very cool...

Brian

 

Interesting, I wonder why they didn't go all the way down to the oil control ring...

 

Yep, that's what I'm wondering. I was planning on having them milled down a little further anyhow, so I'm wonding if I should leave that ring there or take it all the way into the outter ring...

 

Maybe the oil control ring wouldnt seat or seal properly

Interesting, I wonder why Mazda started doing this??? Maybe insead of them being truley "new" they are remanufactored and cut down to get rid of wear signs or something. lol

Of course I guess if that was the case the apex seal grove wouldnt meet spec.

STEPHEN

 

I doubt if they are re-manned! This increases the clearance, & imitates what is commonly called "race clearance" here on the forum.

 

Well, since you're so upset with them I'll give you tree-fiddy for both. heh

Seriously though. I took a look at them in person it is a very noticeable step. You ought to measure the thickness of these rotor's vs a set without the stepping.

I'm speculating that the area my the oil ring is the standard thickness and they are slightly "clearanced" towards the sides seals. Either way, I'll still give you treee-fiddy.

 

I did measure them, that's where I got the ~.002"

 

I missed that.

 

That's alright, it's early...

 

its prolly to keep a full heat dam for the outer oil control ring, and then the tips of the rotor are clearenced,.. arnt the tips the only things that hit anyhow?