Hi,



I am what you would consider a noob. I've been silently surfing nopistons.com for about four months now. Anyways, here is what I am building.



Project: 1986 n/a fc rebuild



Scope: to build a quality street car that can/will be used on the track in the future. full rebuild from ground up - suspension, body, engine, all systems



Engine solution:



S4 irons streetported with Pineapple Racing large streetport template

T2 rotor housings ported with Pineapple Racing template

S5 Rotors with Mazda Comp race bearings

ITB set-up (have to research more before I know the specs)

Eccentric shaft out of the S4

RX-8 front/rear stationary gears and bearings

T2 oil pump

FD rear oil pressure regulator / shimmed front regulator

Fuel cell with upgraded fuel system (have to research more before I know the specs)

OMP removal including gear shaft (set screw in the front iron will block off the oil feed to the OMP)



I have read the post and done the research and know that I won't be pushing crazy horsepower. I'm in it for the build, and like knowing there aren't many with a strong built 2 rotor n/a.



My question right now is I bought two used S5 rotors from a credible source. I received them and have begun to inspect them. (i am waiting for my micrometers to come in so i can't check the clearances yet). Just at initial glance;



One rotor's faces are smooth and the others has a machined feel to it, why do they have a different finish?

There are a few tiny nicks in some of the edges of the rotors. (they appear to be casting imperfections). One small nick is on the edge where the apex seal sits and the others are minute along the edge between the rotor land and the faces. Are these small "nicks" normal or is this something that i should be concerned about?



On one of the rotor gears, there is a tiny groove in one of the teeth. It almost looks like a screwdriver nicked the tooth. Is this a problem and could it cause gear failure? If yes, how do I replace the rotor gears? I have my S4 rotors (very low mileage and in great condition) that i could use as a donor.



Thanks in advance for your reply's.



Regards,



Greg B

Gardner, MA

 

You need to post some pictures up. Some imperfections are acceptable and others are not. It is really hard to tell without seeing what exactly you have.

 

Makes sense. Clarity isn't perfect but...



[attachment=45947:Picture3.jpg][attachment=45946:Picture2.jpg][attachment=45945:

rotor_1.jpg]

 

*Note: the picture with no red circle shows a small chip in the edge where the apex seal sits.

 

thoughs are fine and usable. i wouldnt worry too much about the chips . the chips shouldnt affect anything as far as compression or runabulity of the engine.

 

yep little stuff like that is fine. id smooth it out, you dont want it collecting carbon and being a hot spot, or something dumb



rotor finish; it seems as though mazda has two machines. one spits out a really nice smooth faced rotor, and the other a really grooved looking rotor face.



its weird but normal, new rotors are like that too

 

Thanks guys, that's reassuring. When you say smooth them out. What would i use to do so? 600 grit wet/dry sandpaper?



Also, I've seen that some people like to "polish" their rotors before assembling. If i wanted to do this what is the correct procedure? is it worth the effort meaning does it affect anything other than looking beautiful?

 

600 is fine, file might be a bit quicker for the "damage"



ive polished em with 600 grit paper, i only do the faces. i haven't really noticed a difference with the polished vs non polished. but its only 2 engines worth

 

I would use a small file on them and then maybe hit it with some sandpaper to smooth it out....

 

be sure apples are apples

2mm apex rotors with cast finish in the bath are s4 rotors,, turbo ones have a cast mark in the bath like a struck 'I'



2mm apex rotors with a machined finish apex to apex through the bath are s5 or s6 rotors