Superblend .. FAG reply

I recently wrote to FAG Bearings Technical department as regards the "Superblend" Bearing....Mr Neil Wright very kindly replied (shown below)...I will contact him further as regards to obtainfurther clarifications...

Hello Les

With reference to FAG cylindrical roller bearing NU306-E-M1,,, I assume your application is on the crank and brgs are set into an aluminium hosing, for this reason I am expecting the bearing that was originally specified was âC3â increased radial internal clearance (refer to as attached drg).

Due to confidentiality reasons I am unable to supply a detailed drawing of the rolling element used in this bearing, refer to the following drawing snippet that details the roller diameter profile;

Essentially all rolling bearings have a rolling element with a profiled form, this is so as to prevent âedge loadingâ during high load or misalignment. As you will see from the sketch above this profile is determined by measuring the drop-off at various âgaging pointsâ .

I suspect that during the early to mid 1970âs FAG would have supplied a version of this bearing with a slightly crowned inner ring raceway (identified with the additional suffix; â?BL), this allowed slightly more misalignment capability hence preventing damage by crankshaft flexing during high load. Norton coined the term â Superblendâ even so this was never recognised by FAG locally when Norton or respected spares supplier ordered the bearing.

Superblend (FAG suffix â?-BL ) was never the standard bearing, to achieve the same specification we now use the suffix; QP51 in place of BL, however you do really need to check for current availabilities or MOQâs of NU306-E-M1 (or M1A â outer ring guided cage) âQP51â? from one of our suppliers.

I hope this will be of help to you, are you experiencing failures with using the standard part (i.e. with-out suffix BL or QP51)? if you can supply additional details of your application and possibly failed brgs (or even detailed photos of rolling marks on raceways / rolling elements) I my be able to advise further.

Best regards

Neil Wright

Product Engineer

INA FAG

......................................

My understanding of what Neil is saying is that all NJ306 bearings are standard....and one should buy a C3 clearance version...BUT should you experience mechanical problems you should try to obtain the NJ305 with BL or QP51 variants as these are profiled a little more ....I guess not many of these are currently installed in most peoples engines?

PS...Sorry about the mix up with the NJ and NU prefix....that was my fault....but the bearings are the same apart from the end flange on the inner race of the NJ....all other details are the same...