Well, you REALLY need to pull the pan and find out what's making the noise!
I'm assuming the obvious was checked -- is there a dent in the pan? Clearances are tight in a few spots in a lot of motors, it could be a dent pushed metal up to a rod stud, etc.
If it's a smooth dent, you could probably grind the pan rough, epoxy a plate to it with a tapped hole, as a dent-puller and get a few .01's better clearance.