Crank Thrusting Foreward Issues

OK, was wondering if the thick washer was there. It is important for clamping force to lock the damper to the crank. Were you able to get the full torque on the long bolt into the crank snout? How long is the long bolt and how much threading is into the crank snout?

I'd take this stack up apart and look for evidence of movement and in the damper key way. And make sure this long bolt is not too long and bottoming in the hole in the crank. You may well find nothing wrong, but it is easy compared to pulling the pan! If nothing bad, then off with the pan.....

Just as an aside: The one problem that I think you could have with this stack up is that the clamping force has to be transmitted through a whole series of metal to metal interfaces, rather than just 2 (bolt head to washer and washer to damper). These all give the chance for movement, and if they are plated washers, that is even more likely. That stack of washers should be replaced with a solid steel sleeve. Understand that the damper is being locked to the crank with the bolt and thick washer; this is what actually transmits the high frequency crank vibrations that the damper is designed to counter. So, if you have even a miniscule amount of movement in the bolt clamping setup, it can interfere with the damper action.