Bearing Clearance On 13b
07-20-2003, 08:06 PM
#1
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Thread Starter
Join Date: Jun 2003
Location: Helena, AL
Posts: 96
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?
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?
07-20-2003, 11:38 PM
#3
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Join Date: Jun 2003
Location: Helena, AL
Posts: 96
Originally Posted by rxseven' date='Jul 20 2003, 06:47 PM
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.
07-21-2003, 12:25 PM
#4
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Join Date: May 2002
Location: California
Posts: 22,465
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
mike
07-24-2003, 03:24 PM
#6
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Join Date: Sep 2002
Posts: 2,550
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 
) 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
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
07-24-2003, 05:06 PM
#7
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Join Date: Jun 2003
Location: Helena, AL
Posts: 96
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?
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?
Originally Posted by Dragon' date='Jul 24 2003, 12:24 PM
Stationary Gear Bearings
T=1.980mm yellow NF01-10-E04
T=1.983mm green NF01-10-E05
{ SNIP }
T=1.997mm black NF01-10-E25
T=2.000mm blue NF01-10-E26
T=1.980mm yellow NF01-10-E04
T=1.983mm green NF01-10-E05
{ SNIP }
T=1.997mm black NF01-10-E25
T=2.000mm blue NF01-10-E26
07-25-2003, 01:11 AM
#10
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Join Date: Sep 2002
Posts: 2,550
Originally Posted by KorovaKharne' date='Jul 24 2003, 02:06 PM
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?
[quote name='Dragon' date='Jul 24 2003, 12:24 PM']
Stationary Gear Bearings
T=1.980mm yellow NF01-10-E04
T=1.983mm green NF01-10-E05
{ SNIP }
T=1.997mm black NF01-10-E25
T=2.000mm blue NF01-10-E26
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?
[quote name='Dragon' date='Jul 24 2003, 12:24 PM']
Stationary Gear Bearings
T=1.980mm yellow NF01-10-E04
T=1.983mm green NF01-10-E05
{ SNIP }
T=1.997mm black NF01-10-E25
T=2.000mm blue NF01-10-E26
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 *** okinawa sun..