wrankin

Pardon if this is a FAQ. I searched but could not find an answer.

As we all know there are several different rotors available for 13B's. S4-NA, S5-NA and TII's all have different compression ratios. So my question is if you are holding a single rotor in your hand without another to compare it to, how could you tell if it is an S4, S5 or TII rotor?

Thanks,

-bill

RotaryEvolution

iTrader: (30)

isn't much info available that i could find either, the only way i could tell them apart was by the depth of the relief pockets in the rotors. i have S4 both T2 and n/a rotors that i can measure if you want to find out if you have either of those. i always mark my rotors when i put them on the shelf, keeps from having a problem like this.

alexdimen

iTrader: (13)

you can tell s5 from s4 by the surface texture of the pockets on the three sides of the rotor. on a s4 it will have a rough, cast look to it and on a s5 the pockets look machined and have little machining lines.

s4 rotors also weight more than s5 rotors by about 1/2 lb to 1 lb. (i forget) so you can tell if you have a really accurate scale.

make sure you also match weight stamps. i've only done NA work so i don't know about tII ... but karack seems like hes got it down.

alexdimen

iTrader: (13)

comparison chart

http://www.mazdatrix.com/faq/rotorwgt.htm

RotaryEvolution

iTrader: (30)

thanks, i forgot about the machined reliefs in the S5 rotors. i just don't have the pocket depths written down because i never needed to verify rotors before.

wrankin

Thanks guys, the weights are a good giveaway. Also the machine lines.

One thing that I noticed is that when I was searching through a pile of rotors - I found a couple with a machined pockket, but I also found a couple where the entire faces had machined lines, rather than the smooth face of the other S5 rotors.

The plot thickens.

Thanks for the info.

-bill

RotaryEvolution

iTrader: (30)

i have seen some rough machined rotor faces also, i don't think that means much just that the machining bits were worn when they were making the rotors. my mazda reman had one smooth finish rotor in and one rough machined rotor, the engine runs fine with one of each in it.