Well, the pulley is not that hard to inspect. (sounds more like the tensioner went south to me). Just look at the rubber between the outer ring and center section of the pulley, if it protrudes, its bad, if the front face of the 3 parts are not aligned straight, its bad however, these are more known to make these interesting scraping sounds rather than a rattle. Look at the tensioner while running and see if its hammering, turn the wheel full lock and load the motor while looking at it, if its bouncing in time with the knock, there you go, bad tensioner. The down side to the balancer is the fact it tends to walk rearward and eat the oil pan. The adds up to big bucks especially if it makes contact with the timing cover.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.