Re: Acoustic Insulation for engine room?
I've seen a commercial lead/foam sheet that has a fairly dense black "polyfoam" type of foam with a sheet of lead sandwiched to it and a foil backing on the lead side. How does the group think this might work if you first lined your engine compartment with sheet lead then attached the foam product with the lead side "in" - this way you'd have the foam creating the dead air space between two skins of sheet lead.
It would cost several $hundred but the theory seems to fit well with the comments in this thread.
I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.