I'm not going to even attempt to "run with the big dogs" on this
discussion.
My two cents I got from Robert Williams at Lancair. He said they
remove the padding in the firewall blanket at the engine mount points by picking
it out with needle nose pliers before mounting the blanket to the
firewall. They don't damage the face or the back of the blanket that
way. The padding has a tendency to compress, loosening the engine mount
bolts.
Of course I heard this from Robert AFTER I had my engine installed.
Consequently, I check the torque on my engine mount bolts at each condition
inspection. The first year they were slightly loose, a quarter turn on the
bolt or so to reestablish torque. Since the first year (two more years) no
additional tightening needed.
Mike Easley
Colorado Springs
Super ES