My new car!

chickenwafer · Postby **chickenwafer** » Thu Oct 13, 2011 9:14

Remind me to kick you with one of my wussy legs when you get back! haha.

Going to do some work on the car today. Getting carbon off the rotors and getting them cleaned up, and then painting my LIM and UIM. Still need to polish my alternator but I really don't want to LOL

speedjunkie · Postby **speedjunkie** » Thu Oct 13, 2011 9:14

LOL.

Man I can't wait to work on my car again. But I'm glad I'm not polishing the alternator LOL.

chickenwafer · Postby **chickenwafer** » Sat Oct 15, 2011 9:14

I took up the most fun task any rotary owner can today- cleaning old engine rotors....

Luckily my rotors weren't as carbon'ed up as some I've seen, but they did have their fair share. Here is what I started with:

One face done:

And done, only 2 1/2 hours later:

As I removed the carbon, however, the rotor revealed it had some *minor* nicks and "damage". Wanted to post these up and see if anyone has any concerns about these:

First if this nick in-between the bathtub and apex seal slot, you can see it centered in the picture. Then, if you move your eyes slightly down and to the right you can see a very clear #7 stamped into the rotor. I've never seen Mazda actually stamp rotor faces before (only the sides) so this was odd to me:

Another angle and closer to the #7 stamp:

Another issue: on a different rotor face, again about halfway in-between the bathtub and the apex seal slot, some heavy scratching. This was not caused by me in an effort to remove carbon, they are kind of deep so I have no way of damaging the rotor like that. Due to the reflection of light it looks dented almost and I thought it was at first as well but I can't tell in person, it feels straight:

Last is the only one that really concerned me. It's on another face and right up against the apex seal slot. It doesn't appear to compromise the apex seal slot, but it is very close. Some pictures:

This is from the opposing face of the nick near the apex seal slot pictured above. This is why I don't feel it compromises the apex seal because the chip isn't visible from the opposing face:

Last one, head one:

So what do you guys think? I know the other nicks and minor chips are nothing, I'm only marginally concerned with the chip near the apex seal groove.

iani1.1 · Postby **iani1.1** » Sat Oct 15, 2011 9:14

im anal about nicks and scratches on rebuilds. to me its trashed.

speedjunkie · Postby **speedjunkie** » Sat Oct 15, 2011 9:14

I had a good size dent on the face of a rotor one time and I didn't use it. I've had nicks where they bent over a corner of the apex seal groove and I didn't use that rotor either. Other than that, I wouldn't worry too much about it. I can't see the pics right now due to the computer I'm on, but as long as it's not a serious dent/anything that could eventually be a hole in the face, and as long as it's not a nick on the edge of the apex seal groove or on the edge of the rotor to where it would sit abnormally on the face of the iron and cause damage, I think you'd be fine.

chickenwafer · Postby **chickenwafer** » Sat Oct 15, 2011 9:14

iani1.1 wrote:im anal about nicks and scratches on rebuilds. to me its trashed.

I'm anal, too, but how does a small nick or scratch on a rotor somehow question it's performance? It's cast iron, I'm no metallurgy specialist but I can't see a small nick or scratch compromising the rotors structural integrity.

Other than that, I have no clue how a small scratch could somehow damage an engine?

speedjunkie wrote:I had a good size dent on the face of a rotor one time and I didn't use it. I've had nicks where they bent over a corner of the apex seal groove and I didn't use that rotor either. Other than that, I wouldn't worry too much about it. I can't see the pics right now due to the computer I'm on, but as long as it's not a serious dent/anything that could eventually be a hole in the face, and as long as it's not a nick on the edge of the apex seal groove or on the edge of the rotor to where it would sit abnormally on the face of the iron and cause damage, I think you'd be fine.

No dents whatsoever, but it does have a small chip very close/on the apex seal slot, but it doesn't look to bad.

I can't just replace one rotor without re-balancing the entire rotating assembly, which is something I'd have to ship the rotors, e-shaft, flywheel and potentially the clutch and pressure plate out for, which I really, really, don't want to do. The alternative would be to buy two new matching weight rotors, but again, more $$$ for something I don't think is a problem.

VRx8 · Postby **VRx8** » Sat Oct 15, 2011 9:14

I think you should be fine, if it doesn't affect the apex from going up and down and you get the proper clearance it should be fine.
Good job on the rotors BTW blinging.

speedjunkie · Postby **speedjunkie** » Sat Oct 15, 2011 9:14

Actually I believe you'd be alright as long as you found another rotor in the same weight class. A, B, C, whatever. But it doesn't look too bad as far as damage. The nick right on the apex groove looks like the worst, but like Eduardo said, if it doesn't affect the movement of the seal, you should be fine. How deep is that dent?

Also, now that I can see pics, Eduardo is right. BLINGING man. Holy crap it looks new.

Oh I've never seen them stamp the numbers on the face either. That's weird.

chickenwafer · Postby **chickenwafer** » Sun Oct 16, 2011 9:14

Thanks Eduardo! I don't think it compromises apex seal movement at all. I only have the factory 3-piece seals right now so once I get my Atkins 2-piece seals I will test out movement and fitment/clearances with the springs.

And Eric, I thought about being able to buy a new/used same weight order, but I would feel better about balancing the rotating assembly or getting two new matching weight rotors. I guess it could work since I don't plan on revving past 8000rpm anyways.

speedjunkie · Postby **speedjunkie** » Sun Oct 16, 2011 9:14

What I mean is I don't think engines normally have a balanced rotating assembly anyway other than having two matching weight rotors. Unless someone pays for it. Otherwise you wouldn't see people buying just one rotor all the time on the forums. I doubt all those people are getting their engine balanced, that's why they're looking for whatever rotor matches the one they have already. Know what I mean?

chickenwafer · Postby **chickenwafer** » Mon Oct 17, 2011 9:14

Yeah I get you now Eric, I had to think about it initially haha.

The rear rotor I completely cleaned looks to be a "C" weight rotor, but the front rotor which I started cleaning last night doesn't appear to have a clear weight stamp on it? Most consistent letter I can find is "F", I think, which means they are mis-matched anyways if that's the case LOL.

I check with Mazdatrix and Atkins and they recommend ordering rotors in pairs as they usually can't guarantee which weight rotors they have in stock so it's a crap shoot getting the weight rotor you need.

Of course they recommend balancing the rotating assembly, and this is a service they provide and charge for. So I wonder if they just say that to get your business? Mmmmm. I'd probably try to find a used rotor anyways, but I don't think that rotor needs replacing.

VRx8 · Postby **VRx8** » Mon Oct 17, 2011 9:14

I saw 2 fd rotors on ebay "great condition" for 400
http://www.ebay.com/itm/1993-1995-Mazda-Rx7-Engine-Rotors-FD3S-FD-Wankel-/170713700622?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item27bf54590e

chickenwafer · Postby **chickenwafer** » Mon Oct 17, 2011 9:14

Thanks Eduardo! I wish the seller had posted better pictures, you can't see anything relevant as to condition from those side-face shots.

iani1.1 · Postby **iani1.1** » Mon Oct 17, 2011 9:14

idk, any nick or scratch to me i think messes with the structural integrity. i mean, some times it may look like a scratch but its really a crack. ya know? also heat which makes the metals expand and contract also plays a part in further damage. in short i need it in perfect or near perfect condition before i put it together. thats just me. also measurements and crap dont get me started LOL

speedjunkie · Postby **speedjunkie** » Mon Oct 17, 2011 9:14

I don't understand why they can't tell what weight rotors they have, unless they are like yours and don't have a stamp. I sure hope you haven't been using an F with a C lol. They are probably pushing their balancing job, that's what I was thinking when you first mentioned it haha.

Man, if I was home I would see if I could get it x-rayed at our NDI (Non-Destructive Inspection) shop on base. When I was changing my suspension bushings I bent one of the rear lower control arms and NDI did an x-ray on it for me and I even kept the "picture" lol. But I'm guessing you want to have this thing finished before January huh? lol

$400 is a pretty good price on rotors, as long as they aren't messed up anyway. I paid $600 back in 08 for two practically brand new rotors, they had only been used to break in a reman, but usually they're about $600 each.

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