Main bearings

bryan_woods said:

I noted that the SKF bearing has 11 rollers and the FAG 12

Click to expand...

The SKF bearing shown is the gearbox layshaft bearing ( I did mention *layshaft* bearing). I was only pointing out that both SKF bearing parts were marked differently, so the FAG could be marked up the same way (and not an old NJ inner track used with a new NU outer bearing).

My apologies L.A.B need to read more closely.

Main Bearing Part Numbers and Main Bearing Clearances

It appears that FAG and SKF assemble different bearings (NJ, NU, NUP, HJ, etc.) with parts common to various bearings.
I also have the NU306E outer race and the NJ306E inner race and I am sure that my motor has not been opened previously. The NU306E outer race is exactly the same as the NJ306E outer race, so if you have either there is not cause for concern.
Also, the picture on CNW's web site supports this, the NU outer race is the same as a NJ outer race.
Asking for a replacement bearing can be a little tricky as you need to write down all the markings lest you end up with the wrong bearing - better yet, just take them the whole old bearing.

As we can't imagine the accuracy that all the components are made to (and the fact that all manufactured parts from quality bearing companies are 'exactly' the same - DAMHIKTBIKT) it isn't worth concern.

I do have a question about the clearance in the main bearings.
Some posts state the main bearings should have a clearance of C2 (which is 0 to 25 microns - and tighter than the C0 clearance of 20 to 45 microns), but others state C3 (35 to 60 microns).
NJ306E.M1.C2 or NJ306E.M1 or NJ306.M1.C3
Which is it? :?

I looked up SKF versus FAG.
The FAG is rated at Cdynamic=51000N and Cstatic=48000N.
The SKF is rated at Cdynamic=51200N and Cstatic=48000N.
If the FAG bearing has a different number of rollers than the SKF, the catalogs don't suggest a capacity difference.

Hi there. Interesting posting, as I have always insisted on my bearing supply dealer to give me FAG and not SKF , and I don't know why, I had got both in my hand and they are little bit different about the bronze cage, not riveted identical........I have seen too on other forum that BDM
( miss this one..) advise C2 clearances , but it was about Atlas and he said the crank was pretty much stiffy to turn when cold , but everything was OK when hot , it was supposed to help the vibes on the low side, while reducing top end and bottom end play, seems clever.....