If its damper you will have a pretty significant vib level at blade passing frequency and also at 2R.
I have emailed you, if you haven't got it pm me, I have a bunch of ideas. If I am reading your post right, you have 1R Vert reading of 1.6 i.p.s.?? or is it 0.16 i.p.s.? If 1R is 0.16 then my supporting questions and other data requests will make sense.