Identify These Rotors
#3
I hate drum brakes
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^They're LDR rotors, not the standard MDR that the 13B uses.
Soak them in a bucket of 50:50 water and Zep industrial purple cleaner for a day, and wipe with a brush to get all the crap off of the metal, then spray with compressed air, WD40 and more compressed air, then post more pics.
Soak them in a bucket of 50:50 water and Zep industrial purple cleaner for a day, and wipe with a brush to get all the crap off of the metal, then spray with compressed air, WD40 and more compressed air, then post more pics.
#5
I hate drum brakes
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Rotors are cast iron, and yes. I threw an old aluminum piston in the bucket for the hell of it, and it became porous and black, like pavement. My rotors looked brand new with no carbon/brown/varnish on them. Even though my bearings looked perfect after the cleaning, I changed them anyway.
#6
Rotoholic Moderookie
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Well I'll throw one thing out there : They should be 12a rotors So that will eliminate a great many choices of what they could be.
I'm going to be acquiring these from alexdimen and was wondering if there was a way to find out if they were from an S1, S2 or S3 motor just by looking at them. I'm hoping they're 84-85 rotors because that's what I already have the rotating assembly for.
And yeah, these will be home to a set of "Race Rotor Bearings" from either Mazdatrix, RacingBeat or Atkins, so alex if you've got some cleaner, soak away!
Jon
Edit: I bet if we got Jeff20b in here he could figure them out.. he's really good at identifying engine bits.
I'm going to be acquiring these from alexdimen and was wondering if there was a way to find out if they were from an S1, S2 or S3 motor just by looking at them. I'm hoping they're 84-85 rotors because that's what I already have the rotating assembly for.
And yeah, these will be home to a set of "Race Rotor Bearings" from either Mazdatrix, RacingBeat or Atkins, so alex if you've got some cleaner, soak away!
Jon
Edit: I bet if we got Jeff20b in here he could figure them out.. he's really good at identifying engine bits.
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#12
Apathy Isn't Laziness
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Should be 3mm if it's from any 12a engine 79-85.
#13
Rotoholic Moderookie
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Yeah, all 12a rotors were 3mm. They only went to 2mm in the FC 13b.
That's perfect though because those pics look 3mm, and that's what 12a rotors should be, so everything's on track.
I guess it's not a huge deal if it's 81-82... just means I'll need a different set of counterweights. I'm getting the rotating assembly rebalanced for high-rpm anyway, so no biggie.
I still want to see those pics this weekend though!
Jon
That's perfect though because those pics look 3mm, and that's what 12a rotors should be, so everything's on track.
I guess it's not a huge deal if it's 81-82... just means I'll need a different set of counterweights. I'm getting the rotating assembly rebalanced for high-rpm anyway, so no biggie.
I still want to see those pics this weekend though!
Jon
#15
Super Moderator
iTrader: (3)
That's true, T.
Also, besides the width of the rotor, you can tell 12A vs 13B as the 12A has an asymetric combustion dish (F rotor, R rotor), while the 13B has a symetric dish (interchangeable).
Jon is such a n00b. Actually, I just remembered that recent thread that waysrx7 posted a link to. I didn't search. In the pic waysrx7 shows in that thread, at first it is hard to see the N and the R. But if you look hard enough, you'll see them.
Also, besides the width of the rotor, you can tell 12A vs 13B as the 12A has an asymetric combustion dish (F rotor, R rotor), while the 13B has a symetric dish (interchangeable).
Jon is such a n00b. Actually, I just remembered that recent thread that waysrx7 posted a link to. I didn't search. In the pic waysrx7 shows in that thread, at first it is hard to see the N and the R. But if you look hard enough, you'll see them.
#20
Apathy Isn't Laziness
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#21
Yeah, all 12a rotors were 3mm. They only went to 2mm in the FC 13b.
That's perfect though because those pics look 3mm, and that's what 12a rotors should be, so everything's on track.
I guess it's not a huge deal if it's 81-82... just means I'll need a different set of counterweights. I'm getting the rotating assembly rebalanced for high-rpm anyway, so no biggie.
I still want to see those pics this weekend though!
Jon
That's perfect though because those pics look 3mm, and that's what 12a rotors should be, so everything's on track.
I guess it's not a huge deal if it's 81-82... just means I'll need a different set of counterweights. I'm getting the rotating assembly rebalanced for high-rpm anyway, so no biggie.
I still want to see those pics this weekend though!
Jon
I know these are 12A rotors for a fact. I personally pulled this engine from a car in the lot at chesterfield auto parts.
I've got the rotors in front of me. They have F and R stamped in the dishes. There is no N. So, that makes the 81-82?
#22
Lapping = Fapping
iTrader: (13)
Yeah, or '78 to '80. What does the front counterweight look like? Half circle or less than half circle?
'78-'82 had the same weight rotors but the front counterweight was different. When Mazda went to a lighter flywheel in '81'-82, they had to use a lighter front counterweight (the pone that looks like less than a half circle). The rotors themselves remained unchanged from '76-'82.
'83'-85 front counterweights are more of a quarter circle.
'78-'82 had the same weight rotors but the front counterweight was different. When Mazda went to a lighter flywheel in '81'-82, they had to use a lighter front counterweight (the pone that looks like less than a half circle). The rotors themselves remained unchanged from '76-'82.
'83'-85 front counterweights are more of a quarter circle.
#23
Eats, Sleeps, Dreams Rotary
iTrader: (1)
Here's a chart to identify what rotors you have.
http://www.mazdatrix.com/faq/rotorwgt.htm
You have to take all the springs and seals out of the rotor, clean it, and then weight it and use the chart to identify what 12a rotor you have. I just pulled my engine apart and I had no idea what was inside. My rotors came out at 9.5lbs each so I have the 83-85 rotors. My rear flywheel was out of an 80-82 12a. So there was probably a balance issue with my motor.
http://www.mazdatrix.com/faq/rotorwgt.htm
You have to take all the springs and seals out of the rotor, clean it, and then weight it and use the chart to identify what 12a rotor you have. I just pulled my engine apart and I had no idea what was inside. My rotors came out at 9.5lbs each so I have the 83-85 rotors. My rear flywheel was out of an 80-82 12a. So there was probably a balance issue with my motor.