rotor questions...
10-03-2008, 03:42 AM
#1
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Thread Starter
Join Date: Feb 2005
Location: Kissimmee FL.
Posts: 1,579
i have a few spare rotors and wanted to see if there usable. at first glance theres no digs, scrathes, or any scarring on them. but how would i check further to make sure the rotor is in good enough shape to use? like clearences where seals and springs go.
does anyone have a complete list of what rotor weights (the letters) go with eachother?
and how would i tell the difference between the rotors? s4 na - s5 turbo ect...
does anyone have a complete list of what rotor weights (the letters) go with eachother?
and how would i tell the difference between the rotors? s4 na - s5 turbo ect...
10-04-2008, 06:47 AM
#2
Junior Member
Join Date: Apr 2005
Location: ar
Posts: 19
Originally Posted by sen2two' post='909088' date='Oct 3 2008, 03:42 AM
i have a few spare rotors and wanted to see if there usable. at first glance theres no digs, scrathes, or any scarring on them. but how would i check further to make sure the rotor is in good enough shape to use? like clearences where seals and springs go.
does anyone have a complete list of what rotor weights (the letters) go with eachother?
and how would i tell the difference between the rotors? s4 na - s5 turbo ect...
does anyone have a complete list of what rotor weights (the letters) go with eachother?
and how would i tell the difference between the rotors? s4 na - s5 turbo ect...
any FSM should have the clearances your looking for, minimum tools feeler gauge for apex/oil seal clearances. as far as weights that go together its one letter apart up or down (B can go with A or C). i cant remember how to tell exactly which rotors you have but mazdatrix.com has a link on thier page that tells rotor weights for the different years models. i know that like the s6 rotors are milled faces but like the 8.5 s4 rotor faces are cast not sure on s5. as far as compression for NA vs turbo dish depth maybe????
z
10-06-2008, 07:02 PM
#7
Senior Member
Join Date: May 2002
Location: California
Posts: 22,465
there might be a rotor spotting guide somewhere in the FAQ's, but heres the quickie version.
74-85 13B, cant miss these, 12lbs, 3mm apex seal gooves, 1mm side seal groove, cast combustion chamber.
86-88 N/A 10.5lbs, 2mm apex and .7mm side seal grooves. cast combustion chamber 1/2" deepish
86-88 TURBO like the na but the combustion chamber is deeper, like 1.5" (the other thread has actual measurements from real, free range grass fed rotors)
89-91 NA 9.5lbs, machined combustion recess
89-91 TURBO 13bt and cosmo, machined combustion recess (in the sae paper they say the cast ones vary by half a point of compression, the machining is +/- .1ish, so if the older 8.5 rotors vary between 8:1 and 9:1, they made the new rotors 9:1, the upper end of the tolerance). again the turbo is deeper, than the NA.
93-2003 FD, the same as the previous turbo rotors, except they have some chrome plated grooves for wear resistance, not really visible.
New ROTORS. if you have rotors that were made AFTER 2005ish, they have additional side clearance like the rx8, or like racing beat will do for high rpm operation.
they letter weghting system only applies to that BATCH of rotors. so unless you're dealing with a factory matched pair, its BS. and i've looked, all the rotors i have out of engines (about 8) are stamped C. you're better off cleaning em really well and using a gram scale. or better yet, have the assembly balanced
74-85 13B, cant miss these, 12lbs, 3mm apex seal gooves, 1mm side seal groove, cast combustion chamber.
86-88 N/A 10.5lbs, 2mm apex and .7mm side seal grooves. cast combustion chamber 1/2" deepish
86-88 TURBO like the na but the combustion chamber is deeper, like 1.5" (the other thread has actual measurements from real, free range grass fed rotors)
89-91 NA 9.5lbs, machined combustion recess
89-91 TURBO 13bt and cosmo, machined combustion recess (in the sae paper they say the cast ones vary by half a point of compression, the machining is +/- .1ish, so if the older 8.5 rotors vary between 8:1 and 9:1, they made the new rotors 9:1, the upper end of the tolerance). again the turbo is deeper, than the NA.
93-2003 FD, the same as the previous turbo rotors, except they have some chrome plated grooves for wear resistance, not really visible.
New ROTORS. if you have rotors that were made AFTER 2005ish, they have additional side clearance like the rx8, or like racing beat will do for high rpm operation.
they letter weghting system only applies to that BATCH of rotors. so unless you're dealing with a factory matched pair, its BS. and i've looked, all the rotors i have out of engines (about 8) are stamped C. you're better off cleaning em really well and using a gram scale. or better yet, have the assembly balanced
10-07-2008, 03:15 PM
#8
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Thread Starter
Join Date: Feb 2005
Location: Kissimmee FL.
Posts: 1,579
the reason i asked was cause when i built my motor a while back. i had two C weight rotors. i thought i was just looking at the wrong area for the weight. so i just tryed putting them back the way i thought i took them out. but i am always thinking i put them backwards...
oh, and it was a JDM TII motor. when i opened it up, it had FD corner seal springs and everything looked new. the rotors barely had any carbon on them. it looked like the rotors had been balanced cause there was some material removed from one of the faces on the rotors that isnt there on other rotors i have had. im pretty sure i got a rebuilt motor with very low miles and some decent upgrades in there... pretty sweet deal. but i can never be sure of it...
oh, and it was a JDM TII motor. when i opened it up, it had FD corner seal springs and everything looked new. the rotors barely had any carbon on them. it looked like the rotors had been balanced cause there was some material removed from one of the faces on the rotors that isnt there on other rotors i have had. im pretty sure i got a rebuilt motor with very low miles and some decent upgrades in there... pretty sweet deal. but i can never be sure of it...
10-10-2008, 07:43 PM
#10
Senior Member
Join Date: Jun 2004
Posts: 524
I'm **** retentive, when I pull an OEM engine apart, I mark the rotors as to their orientation in the engine... which tip was down on one rotor and which one was up on the other rotor, as well as which was was front and rear. That way I'm super special sure that it will go back together the way Mazda did.
I even do it for previously screwed with engines, only because that way I keep the habit. Kinda like using the turn signal even though it's 3am and there's nobody around for miles. And I'm in a parking lot.
I even do it for previously screwed with engines, only because that way I keep the habit. Kinda like using the turn signal even though it's 3am and there's nobody around for miles. And I'm in a parking lot.