What was found
(CAN) WHILE DOING 100 HOUR INSPECTION ITEMS DUE TO ENGINE SWAP TO ALTERNATE A/C, FOUND THAT THE TURBINE CHECK VALVE 23074872 WAS SEIZED WHEN THE CLAMP MS 122911 WAS TIGHTENED. VALVE/CLAMP CONFIGUATION IS CORRECT IAW IPC/CEB1349. CHECK VALVE WOULD FUNCTION WITH CLAMP LOOSE. A NEW CLAMP (P/O 360804) WAS TRIED WITH THE SAME RESULT. THESE CLAMPS ARE FLATTENED IN SHAPE, BY REWORKING CLAMP TO A ROUNDER FORM, THE VALVE WOULD THEN FUNCTION NORMALLY WHEN INSTALLED. THIS WAS VERIFIED BY REMOVAL OF THE OIL SUPPLY LINE TO THE VALVE.