Federal Mogul 6-7120CH-1

[Ttype6]

Looking for the printing on the back side of the bearing. Mine have 001os. I wonder if a set of 6-7120CH-10 would show 010os.

 

[Squid4life]

Yes, 10s are usually .010 over.


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[David Husek]

A .010 bearing would be undersize. The bearing reads .010US.
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[Ttype6]

Yes, 10s are usually .010 over.


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I know that some call a bearing,designed to work on a .010" undersized journal,an oversized bearing.I'm trying to figure out what I have. Two sources tell me that an oversized bearing has extra meat on the outside of the bearing which means it fits into an oversized bore and maintains standard clearance.I'm thinking that the os that federal writes on their bearings means oversized/meat added to the inside diameter of the bearing making for tighter clearances. 99% of the hot rodders in the world would call this an undersized bearing and I think this is technically true. I also have only seen the 7120CH offered as standard,-1,or-10 which leads me to believe that they only come in sizes that would be tighter than the standard clearance. The last thing I discovered was a Federal Mogul bearing through Summit that is sized for a .010" undersized journal/smaller inside diameter and sized to fit into a .002" larger bore. Perhaps you are now as confused as I am.

I need someone to look at a -1 or -10 federal bearing and see if 001os or 010os is written on the back of the bearing.

 

[Ttype6]

A .010 bearing would be undersize. The bearing reads .010US.
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View attachment 189344

This is what I needed to see. These bearings I have,have 001os which must mean oversized. I called federal mogul today and talked to a tech. He told me that this bearing is what I would use if I wanted to tighten up the clearance between the bearing and rod journal. He has to be wrong. However,I don't think it means the same as the Clevite X designation which means .001" extra clearance between the bearing and journal/.001" larger inside bearing diameter. The word oversized,as it relates to engine bearings,means the outside diameter of the bearing is larger/fits in a larger bore. According to what I've read,you would have to enlarge the big bore of a rod by .001" to allow this bearing to fit. The clearance between the bearing and stock rod journal would remain the same. I'll call them tomorrow and see if I can get a better answer.

 

[David Husek]

I had those bearings. When I installed them, to my surprise, I gained another .001 in clearance. I ordered 30 sets from Rock Auto because they were under 2 bucks a set. Too good to be true.....

 

[Ttype6]

I had those bearings. When I installed them, to my surprise, I gained another .001 in clearance. I ordered 30 sets from Rock Auto because they were under 2 bucks a set. Too good to be true.....

I don't see why the inside diameter couldn't come in a larger than stock diameter and be designated oversized as well as the larger outside diameter being called oversized,but there's no definite information to designate which diameter is oversized,none at all on the box and I never found one oversized bearing,on line that referred to a larger inside diameter. I found several undersized/smaller inside diameter bearings referred to as oversized. Some people do refer to bearings for undercut cranks,as oversized because material is added to a bearing to make up the clearance that the undercutting creates. Since you measured it,these must be the same as a clevite x bearing,.001" larger inside diameter. Hey,how about a oid or a ood in the part number or some letters such as X and Y to designate one or the other. ALL THE PARTS YOUR CAR WILL EVER NEED,NOT MINE,ROCK AUTO!

 

[Squid4life]

Okay, i may have misspoke and misguided answering quickly and not thinking it out.

The .001 is usually used on a STD crank to tighten up the clearances and help with oil pressure, as in .001 over. Every .010 bearing i have seen is for when the crank it turned .010 under. Is this making sense?


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[Ttype6]

The .001 is usually used on a STD crank to tighten up the clearances and help with oil pressure, as in .001 over.

Some do call bearings with .001",.010",.020",and .030" smaller IDs oversized,but the correct term for a bearing with a smaller than stock ID. is undersized. The writing on the backs of my bearings is 001os. Since Dave measured these bearings,we now know that these bearings have a larger than stock ID so it stands to reason that the os stands for oversized. The picture of a .010" smaller ID bearing,that Dave provided,shows 010us. This means that Federal Mogul calls a smaller ID bearing ,used to tighten clearances,undersized.