The bearing doesn't control vertical movement, although a thrust washer or a flat needle bearing could be added at the top during the machining process pretty easily. This one is a Torrington needle bearing pressed into a counterbore in the top of the housing that will control lateral movement of the shaft. I lube the upper bearing by inserting a grease fitting in place of the cup, spring and disc. In the process of "blueprinting" the distributor, I also use a dial indicator through the hole for the wiring connector to check the lift of each cam lobe once the lateral play of the shaft is removed, and use a diamond dust needle file to match up the lobes. It's pretty impressive how much error there is in cam lift from lobe to lobe.
Jerry
