Vibration #1 was contact of the left front valve cover with the cowling.  The fix was reducing the height of the valve cover and removing the inner skin and core from the cowl as indicated in the photos.  I verified rocker arm/cover clearance before and after the “fix”.  And nope, the stock Continental cover would not have solved the clearance problem.

 

Vibration #2 was much more interesting.  At about 25 hours, I was over the Cascade Mountains near Redmond when the control stick started vibrating.  At first I thought the engine had gone on Auto-rough due to mountain/night/big water affecting my imagination.  I let go of the stick, still vibrating , so I did not change anything thinking it could be the engine coming apart.  Within easy glide of Redmond I reduced power and it slowly went away.  Fortunately, I had Mark Mahnke available to help trouble shoot.  He suspected the nose gear doors and he was right.  They were just a little too low and when the angle of attack was high enough it would shake.  Leighton Mangels and John Halle have another fix for this by glassing up a little ramp forward of the leading edge of the doors.

 

How many hours were on your isolation mounts when they were “compressed, tilted and cracked“?