I am now in the "measuring" stage of my rebuild. I have all the hard parts cleaned and ready to assemble (still waiting on delivery of 2nd rotor).



Today I spent a few hours with a set of micrometers and a pad of paper. Everything is within specifications except my front stationary gear bearing.

Here is an example of measurments I have taken from it.

1.6960'' <-- too large

1.6955'' <-- too large

1.6934'' <-- too small

1.6926'' <-- too small



I have probably taken 20 measurments on this bearing and out of those maybe 4 of them were within range.



According to the Haynes Manual the limits for this bearing is:

1.6939 to 1.6949



BTW: I cannot find the range of allowable size for this bearing in the FSM. Only the clearance between the bearing and the e-shaft journal. Which is: 0.0016" to 0.0039"



And with the measurments taken from the front bearing journal (all in spec) I only have .0005" clearance between the smallest measurment of the bearing and the largest measurment from the e-shaft journal. This is 0.0011 short from being within spec.



Now to my questions.

Based on these numbers is this bearing garbage?

What does it cost to have a machine shop press in a new bearing?

Is there a "BEST" clearance for power between the journal and the bearing?

Is there a "BEST" clearance for reliablity between the journal and the bearing?

you are getting an error somewhere. the used bearing should usually have excess clearance due to wear. How does the bearing look? Is it showing any discoloration?

The bearing looks great, the only discoloration is on the joint seam as it is supposed to.



If all of my measurments were to the high side that I would just write it off as high mileage. With it having some below and some above the specs it makes be believe the bearing is more egg shaped and not round. What would cause this?



If it the number I am getting was just user error with the micrometer I would probably have the same problems on every bearing and journal I measured this weekend.

well the 2 rotors fire a chamber every 180 degrees so maybe it is egg shaped. its easy to change the bearings if you have the right press tool, they pretty much come right out. or you could try cleaning that bearing up



mike

Just curious, did you check the eshaft roundness with a dial indicator?

the front bearing always wears egg shapped. This is caused 1. by the tension of the belt running the a/c, ps, altenator and water pump pulling up on the front of the e-shaft and 2. because the power stroke of the engine always push's the bearing in the same direction.. It also requires a special tool sold my mazda to press them out (I have one https://www.nopistons.com/forums/pub...) to swap them out. if you look on the side of the bearing you will see a color painted on the side, blue, black, yellow etc.. the problem is their are 2 sizes in each color.. I'm pasting the bearing sizes and colors that are in the parts book I have.. I'm also putting down the part # for the set screw as well since they somtimes get damaged when you try to remove them. If you see any brass showing on the bearing you definitly need to replace it.. Hope this helps you out..



Stationary Gear Bearings

T=1.980mm yellow NF01-10-E04

T=1.983mm green NF01-10-E05

T=1.986mm brown NF01-10-E06

T=1.989mm black NF01-10-E07

T=1.992mm blue NF01-10-E08

T=1.988mm yellow NF01-10-E22

T=1.991mm green NF01-10-E23

T=1.994mm brown NF01-10-E24

T=1.997mm black NF01-10-E25

T=2.000mm blue NF01-10-E26



Station Brng Lock Screw NF01-10-E09

Dragon,

Great information. That explains a lot. I did not know that brass showing was a definate indicator of a bad bearing.



I have a question about the bearing sizes you gave the 1.980mm is that 1.980mm Oversized? 1.980mm thick? How do you know what size to order from the size of the e-shaft journal?



Do you have the bearing sizes for the rotor bearings?

i though it was general consensus to leave the bearings unless they are more then 50% brass color?

Rotor Bearings

3.000 (-0,005 - -0.010) N3A1-11-B11

3.000 ( 0.000 - -0.005) N3A2-11-B11

3.000 (+0.005 - 0.000) N3A3-11-B11



there are only 3 types of rotor bearings..

[/quote]

we beleve the T= the thickness of the bearing, but we haven't gotten a definit answer from mazda.. we usually go with a larger clearanced bearing since we bump up the oil pressure a bit and since we don't expect our engines to last more than 6 months to a year with the power we push them to in the hot ass okinawa sun..

Nope, brass = bad, lots or brass = really fucken bad

The only brass he sees is at the seam which is what is done by mazda to even out the seam. And yes, the mazdamotorsports tech section does say to leave the main bearings alone if they show wear in 50% area or less as they would already have an additional clearance for oil flow. Now egg shaped is a different story.

a new stationary gear bearing is around $35 or so, the rotor bearing is about $30. If your pumping a couple of grand in to a overhaul it's always a good Idea to spring the extra $130's for all new bearings. your only problem is finding the special press tools to pop them out and put the new ones in. If you not in a hurry and you pay the shipping I will do it for you. At the least do the stationary gear bearings as they see the most stress... If you want I'll even order the bearings for you here if you send me the $ for them, you just tell me the ones you want.. PM me if you need help..

Looks like somebody has found a new business niche. https://www.nopistons.com/forums/pub...#>/biggrin.png

I appreaciate the offer but I think I could buy the press tools for less than what it would cost to ship the rotors to Japan.

yah thats the problem with the fd bearings is that they dont list the orginal size ANYWHERE. the pre fd bearings only come in one size



mike

They are around a $100 for each set, one for the rotors and one for the stationary gears.. It took ours about a month and a 1/2 to get here after we ordered them.. https://www.nopistons.com/forums/pub...DIR#>/wink.png If you want I have extra stationary gears that I can put bearings in and send them to you... I also have rotors, but I don't really want to sell those..

do u have pics of any egg shaped bearings?

It would be pointless for me to post a picture of my front stationary gear. It is out of round in the thousandths of an inch. It is not apparent visually, I only noticed it when I measured it with micrometers.