This is the problem.The mirror finish is on the roller is not there because the chemicals i use in the tank puts a protective coating on parts until wiped off or washed off with oil or fuel.
It was mirror when i put it into the tank, the chemicals are harmless to metal its just optical.
When i first checked this it rolled smooth with normal resistance from oil in the bearing, the second time also.
It really looked and felt like all the others, i didn't look at an closer as it had a bad lifter (not on that cyl though).
Even after i got them clean and oil free it still felt okay until i put pressure on it and rolled it on a paper towel. That's when i felt something move.
Then i realized one or more of the needles has a flat spot!
When it moved it was quiet but if it stopped on these needles against the flat spot it would resist moving and knock. The heavier oil also created additional resistance.
The rest are all fine i checked them the same way, the cam thankfully didn't get damaged, the lobe height is within spec.
This one almost beat me.