I am rebuilding my s4na. I have 2 spare s5's for parts. I took apart all 3 motors, the s4 had 2 bad iron housings and 1 bad rotor housing, both s5's had 1 bad rotor and rotor housing. I was wondering, is there a way to visually tell the differance between a s4 and s5 rotors? Also is there a differance between a front and rear rotor and rotor housing? (the s5's had the same bad rotor)
thanks.

 

You can easily tell the difference between rotors. The S5 rotors have a machined bowl, while the S4 are cast.

No difference between front and rear rotor housings in an NA application. The only thing is that you want to keep the apex corner tracing mark toward the rear of the engine as it is stock.

 

apex corner tracing mark??? what dose that look like?

 

Nevermind. I don't know what I was thinking with that post, but the housings only fit one way. Regardless of whether you use a housing on the front or back, the apex tracing mark will always point towards the rear of the engine.

This tracing mark is made by the corner piece of the apex seal. If you look at the rear edge of the chromed surface of each housing, you will see a mark about 2MM wide that traces around the housing. That's the mark made by the pointed end of the apex seal corner.

 

I can only speak for series four rotor housings. There is a difference in rotor housings. At first glance you don't see the difference. But close inspection will show the PORT AIR passage for the ACV air WILL NOT pass into the exaust ports if you put the front in the rear and the rear in the front. So on a series four you will disable the emissions design if you swap the rotor housings.

I don't deal with series five.....but if you look at MAZDATRIX.COM and look for rotor housings, you will see they are seperate part numbers. THERE IS A REASON THERE ARE SEPERATE PART NUMBERS.

On a series four , the rotor housings have a F and a R to designate the housings.

 

Interesting...Is this for turbo or NA? I would swear that my NA S4 housings are exactly the same, but I could be wrong. They do, however, have the F and R stamp. Also, one has the "Produced under license..." stamp.

 

Series four N/A. I can assure you that what I wrote above about series four N/A is accurate to a tee. If one does not give a hoot about ACV and emissions.....then it matters not where the housings go.

There are far tooooooo many people on this forum that have the conception that the Split Air and its pipe are the major players in emissions. Ain't so. Never been so. Ain't never gonna be so. So. humor

 

with the rotors, is there a way to tell the differance between the frount and the rear? is there a differance?

also after giveing inspecting the surfaces of the irons i notaced on one of them a line that i can catch my thingernail in that looks to be on the eadge of the rotor when the combustion sparkplugs are fireing. do i need to get this housing lapped? or is it good or junk.

 

bump