Quote Originally Posted by pat mccarthy View Post
sorry not stepping on any ones toes.. but take it any way you will the bearing are dull out of the box and that finsh is the best to keep hands off
They are babbitt dull (tin/lead/antimony, etc) but are very smooth. The way it was explained to me by an old time engine builder is that they were too smooth - like a non-honed cylinder wall and that they needed some texture to maintain an oil film. I don't buy that explanation and have never done it. The bearings are manufactured to maintain a certain oil film thickness at a certain crank to bearing clearance and with a certain oil feed wedge. While it doesn't hurt to Scotch-Brite, there is no really good reason to do it.

For a short while I worked in a bearing manufacturing area at GE for a while where we actually cast and machined bearings from a couple inches in diameter to over 24 inches. These bearings were finished on a lathe to a particular finish - and that finish was not really smooth. Many years later, I don't recall what that finish was (125 maybe) and these bearings mostly went into constant speed motors and turbines with minimum speeds of 3000 rpm up to over 6000, usually with 25psig oil pressure and operating continuously for years between inspections. As far as assembly in the field - most service engineers used ordinary STPQuarts of that stuff!!

Do it or not, caution plus a good cleaning afterwards is the best way if Scotch-Brite is used.