How much clearance is there between the damper hub and the timing cover? If the front main bearing has gotten worn at some time in the past and let the damper rub the cover, it's possible that the clearance is a lot more than it once was. There should be no more than a few thousandths between the cover and the damper hub, and a close tolerance on the front main bearing. If the spiral groove in the damper isn't fairly deep, it's likely that the damper hub is worn. It would probably be possible to machine the hub down slightly, press a repair sleeve with the right clearance onto it, and re-cut the oil groove.
Jerry