What was found
(CAN) A RATTLE NOISE WAS HEARD AT ENGINE START. CLOSE INSP OF THE ENGINE MOUNT ASSY REVEALED ALL 4 MOUNT SPACERS, P/N 829, HAD SHEARED THEIR ATTACHMENT RIVET HEADS. THIS AC WAS MODIFIED IN THE PAST WITH 180HP CONVERSION. DISASSEMBLY REVEALED THE USE OF VERY SOFT ALUMINUM ALLOY RIVETS TO ATTACH THE ALUMINUM SPACERS TO THE STEEL TUBE MOUNT STRUCTURE, PN 17201-1, WEAR DAMAGE PREVENTED POSITIVE VISUAL ID OF THE RIVET TYPE. IT IS UNKNOWN IF THESE RIVETS ARE A FACTORY OR A FIELD INSTALLATION. FAILURE OF THESE RIVETS ALLOW SPACER TO OSCILLATE LATERALLY ON THEIR MOUNTING PADS. SUBMITTER RECOMMENDS TO EXAMINE THIS ENGINE MOUNT SPACER CLOSELY FOR SMOKING OR LOOSE RIVET HEADS AT INSP. (TC NR 20070216004)