Rpeck

Here is the post I had earlier;
https://www.rx7club.com/forum/showth...ighlight=press

These look pretty worn out to me, I think I should replace them, and what do you think?
Can I get these popped in and out at any place with a good arbor press? Or do I need a certain type of machine to do it? I really don’t want to put my engine together like this, and especially since I already have the bearings I just need them pressed out & in.

Thx

Rpeck

Rpeck

Picture of the new bearing for the old man;

hypntyz7

I reuse those all the time with no problems, but its your engine. In fact, I have not had a set so bad I needed to replace them yet...except one or 2 that were oil starved, which I did not reuse much from.

Rotortuner

No, those bearing look great. used bearings are better than new ones since they have already been broken in adn are harder than when they are stock. They way to tell is if you can see any copper, and you cant at all in those. when you can see the copper which looks like a bronze color or almost redish then its time for new ones. Also on replacing and pressing the new ones thats kinda hard on the rotors. Just use those and youll be good until next time you blow it.

CJG

Rpeck

You don't think that looks like copper showing through on the main bearings? I'ts kinda hard to tell with the flash on the camera.. but they look worse to me in person.

Rpeck

Damnit, I want to do this right! But im not sure what right is I know the break in period goes way up when you replace the bearings .. and I know I risk some sort of problem, or breakage popping them in and and out.. but i'm such a perfectionist it really bugs me to have the parts and not just go all out.

If you guys really think they are fine I will leave them, what if I replace the main bearings and leave the rotor bearing in (they don't look as bad) whats the down side to that?

SilverT2

uh remind me not to buy one of your engines when the time comes..

DaleClark

iTrader: (55)

It's MUCH better to re-use the bearings than to try and install new bearings - remember, this isn't a piston engine, the bearings don't work hard at all.

The "line" you see in the bearing is where the bearing is folded over and joined.

The probability that you will BIG TIME screw up your motor with an install of new bearings is VERY high. Send those bearings you got back for a refund. They look great in the pictures.

Dale

DaleClark

iTrader: (55)

Heh, try and replace 'em yourself - that's one thing that's best left to Mazda to do!

If it ain't broke, don't fix it.

Dale

HAILERS

I made a tool out of a trailer hitch. The ball part in the picture. Had to grind the ball down to a dia small enough to go thru the housing bore. The flange was the perfect size for pressing the bearing out. Fit like a glove.

But you should be able to take these rotors and stationary gears to a auto machine shop and have them press the old out and new in. The tricky part is making sure the TAB is in alignment when you start pressing the bearing in.

Frankly, the bearing do not look bad in the picture. To quote Racing Beat from their *catalog* (which is much more than just a parts catalog by the way)

*All rotor bearings, stock or Mazda Factory Racing, are made from a flat piece of steel which is stamped, rolled, and then hooked together at the joint with a puzzle lock design. This bearing is then coated with copper and plated with .0015 inch of babbit bearing material. The inside surface of the puzzle lock joint area is ground off to eliminate high spots usually resulting a portion of the copper coating being exposed. This appears *to the untrained eye*, to be a worn spot in the bearing, but is in fact normal.*

I highly recommend buying the Mazdatrix and RAcing BEat catalogs. They have valuable tips on racing, building motors, engine swaps, transmission ideas etc.

HAILERS

The bearing tool jpg:

Roy James

Im no engine expert, but just from what i hear on this thread, i personally wouldnt think those bearings are too good. It seems to me in just about every picture there i see a lil wornt/copper spot, but.. it may just be the camera. I dont know, i too, am on my first engine rebuild so im still learning alot. Just my opinion though.

Rpeck

Well the engine is together now ... I did'nt end up changing the bearings. I will let you all know how it goes when I fire it up .. very soon.

Rotortuner

Trust me those bearing were fine. Copper is a totally different color. Its like red, its not even close to that color and you would have noticed. And ya as was already said that one part on there is the "seam". Also as far as replacing your own bearings. The best way to do it is to cut the old ones out and then pry them with a screw driver. A problem with pressing them is that a lot of times it actualy pulls part of the rotor material with the bearing since its such close tolerance. So any ways your good for a long time.

CJG

hypntyz7

That wont be a problem, as I dont sell engines to ******** anyway...

Rotary Racer

Did the you measure the inner dia of the bearings and the outer dia of the e-shaft? If so did is pass Mazda's recommended tolerance? Sight inspection is important but I can’t stress enough to check those tolerances.

Roy James

Yep, that is pretty much the onlyway to know for sure if its good or not, reguardless of the color, if its within specs, its within specs. And, to me, those pics do look kinda like coper, just like a penny or the copper tubing i work with at work... maybe my monitor is messed up.

rxseven

The mazdamotorsports website clearly mentions if wear is seen in less than half the total area, use the old ones.