Another idea; years ago we had the same problem on a 1000 FPM car in Seattle. Drove us nuts, we did everything you guys mentioned above to no avail. Finally one of the Brighter Bulbs among us (you know a guy that doesn't have that blank look on his face typical of most elevator men) Guess the word he used was "Harmonics" It was combination of several things. His fix was to bolt a flame cut cwt filler on angles attached to the bottom of the Xhead. To give you an idea of the set-up. You could sit on the filler and operate the permit ally mounted car top inspection station. He moved the filler in and out until the vibration disappeared. Know it sounds kinda hokey but it worked.
Work Safe All
CC, is this an air dampener( to fix buffeting from wind resistance) or to adjust the hang of the car within the rails slightly different?
Maybe the last resort is to de-rate the load if the heavier weight fixes the problem?
