One method of prevention that I have contemplated is to form an aluminum
(.015 thick?) sheet to match the shape of the cowl in area of concern.  Then
attach it with small studs embedded in 1/4 inch blocks of phenolic and
bonded to the cowl.  These will space the aluminum away from the plastic to
give an air gap.  The advantage would be that the aluminum shield is
protected from engine vibration and it is impervious to oil and other
contaminates.  It can be removed for cleaning, etc.  Anyone done it this
way?

Gary Casey
ES #157, no engine, no heat, no problem