I cannot decide if i should use new bearings. The rotor bearing surface is in great shape but the front main bearing shows a scratch or 2 and there is a patch where the grey coating (whatever it is) has worn off and a bronze area is exposed. About 1/4" x 1/2" area. I have been reading the mazdamotorsports.com tech section in which it says "if the flaking is less than 1/2 the total bearing surface, reuse the bearing as an old one is prefered to a new one"

WTF?? That seems like a lot of wear to me!



Gurus, please confirm this for me so that I may get some peace of mind when I slap everything together. :unsure: :unsure: :unsure:

If you replace the bearings make sure to extend the break-in period.

I noticed similar wear on the bearing of my front rotor. Is this common? I was debating on replacing them also.

I can check some spare stationary gear bearings tomorrow, but I don't think I've ever noticed it.

That would be cool man but if you haven't seen it, it must not be common https://www.nopistons.com/forums/pub...#>/biggrin.png (Isamu bows to the infinite wisdom of 13Bace).

If I can get a good pic tomorrow I will post one of the wear on the bearing.

Yeah, a picture would be a good idea.

Here are a couple of pics I just took.

This one is better

That looks pretty bad to me. It doesn't look like normal wear to me. How do the stationary gear bearings look?

Ok, i did some research into this, looked up some sleeve/journal bearing books. The sleeve would be an alloy of bronze, tin and is "highly leaded". I am assuming the top coat would be the leaded part being an excellent anti-friction material (so don't lick the bearing surface!). Theoretically, there should be no wear because the oil prevents metal to metal contact but since them funky mazda guys put an oil bypass, I am sure that's the main reason for the wear you see. I have similar wear but not to that extent. The only reason i see as to why mazdaspeed recommends using old one even if only half the surface is intact is because this outer layer is thin enough so that the worn bearing is still within tolerance. The std clearance is 0.002". If this made it 0.0025", it may be preferred. Really for race applications don't they have additional clearanced bearings anyway? Damn it, I wish I had an inside micrometer.

I am surprised 13BACE has not seen this before! He seemed to know it all https://www.nopistons.com/forums/pub...IR#>/smile.png

That kind of damage could be from over revving or oil starvation. That's usually what kills bearings.

Interesting point is mazdaspeed tolerances on bearing clearance is more lax than the factory manual. It also says to allow an additional 0.013mm clearance at the rear portion of the rear gear for eshaft flex. It also says for over 8500 rpm operation your clearance should be atleast 0.001" higher. Point is the only way to be sure is actually get a darn inside micrometer. But it does seem that the flaking you see will not put the bearing out of tolerance.

I'm sure they know what they're talking about. Besides the flaking is anything else wrong with it?

thats not too good just redo it .it will be worth it when your turning 10,000 RPMS

To run 10K RPM you should also upgrade the stationary gears and bearings.

Personally, i'm thinking u would be better off replacing the bearing, and wearing the extended breakin period. Far better option than finding out in a few months that u need to pull the engine down again, or having some high rpm failure.

besides the flaking, there is nothing wrong with it. I think i will stick with conventional wisdom and just get another used gear or a new bearing. By the way, is the mazda tool necessary to press the new sleeves in or can any machine shop do it?

Totally replace anything when your engine is in pieces I say. I mean, if you know it's dodgy, or even possibly dodgy, replace it. Saves another rebuild before it's due. And as for replacing rotor bearings, if you get a shop to do it for you, stay and watch the whole time. Took ours in to be done, vise marks all over the surface, corners all bent in, no gap for an apex seal. Major setback.

damn bro, what a waste of a rotor. I am planning on sending it to a rotory shop like mazdatrix and have them install the new bearings. I would gladly pay shipping and get it done right.

Waste of a rotor? Try waste of two rotors, and two new bearings. Think the dude thought I wouldn't notice, myself being female.

Waste of a rotor? Try waste of two rotors, and two new bearings. Think the dude thought I wouldn't notice, myself being female.[/quote]

How could anybody mess up installing rotor bearings?

True, aren't they just pressed in like a regular bearing? Couldn't you do it without putting the rotor in a vice? I should probably change mine.

**** knows how anyone could mess it up. It wasn't so much he messed up putting in the bearing, because he got it in, just that whatever he did before he got it in absolutely wrecked them. I don't know what actually happened, I wasn't there. You'd think you can trust taking something to a shop to be done, but apparently not. https://www.nopistons.com/forums/pub...IR#>/angry.png

Did they reimburse you at all?

And how did you get the title "rotor humper" below your avatar?

Maybe she PM'd vosko to change it, or maybe she's from rx7scene.com?

hey, i want something cool other than F.N.G or whatever it is.

Send vosko a PM. He craves attention.

Send vosko a PM. He craves attention.[/quote]

Just make a few more posts, and you won't be a F.N.G. After 50 posts it will change.

Send vosko a PM. He craves attention.[/quote]

Just make a few more posts, and you won't be a F.N.G. After 50 posts it will change.[/quote]

Hmm.. What does F.N.G mean? I might have to make many more posts to qualify for "rotor humper". https://www.nopistons.com/forums/pub...#>/biggrin.png

Send vosko a PM. He craves attention.[/quote]

Just make a few more posts, and you won't be a F.N.G. After 50 posts it will change.[/quote]

Hmm.. What does F.N.G mean? I might have to make many more posts to qualify for "rotor humper". https://www.nopistons.com/forums/pub...#>/biggrin.png[/quote]

F.N.G.=F*&kin New Guy.

nothing says welcome to nopistons better than putting F.N.G below an avatar of a new member. (as you can tell from the content of this post, I am just trying to cross 50)

Well you're still only at 48. https://www.nopistons.com/forums/pub...1047683785.gif

How the hell did I wind up with so many posts?

https://www.nopistons.com/forums/pub...DIR#>/wink.png ??? https://www.nopistons.com/forums/pub...DIR#>/wink.png

Well I bought a couple of new bearings for my rotors to be on the safe side. I also picked up a new corner seal. They should be here pretty soon, thank you Mazdatrix :bigok:

isamu,

do you need the mazda bearing puller/installer for it or will any machine shop press them in without it?

I don't know. I was thinking you did not need anything special but I could be wrong. Maybe 13Bace better enlighten us. In the manual it just says to use a large vice or press.

You can't go wrong following the manual. a press will work fine, but you have to set it up so that you don't damage the rotor.

Well I replaced the bearings in my rotors a couple of weeks ago. After I looked around a bit more I noticed similar wear on one of the stationary gear bearings, so I replaced those as well. The bearings were actually pretty cheap, and I am glad I changed them