As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
((WS9R)) FOUND ABRASIVE MEDIA TRAPPED BETWEEN THE NR 4 EXHAUST LOBE AND THE FWD THRUST SURFACE OF THE CAMSHAFT. ALSO, BY USING A 10X MAGNIFYING GLASS, FOUND THAT THE CAM LOBES AND MACHINED BEARING SURFACES WERE ROUGH AS IF DAMAGED BY ABRASIVE MEDIA BLASTING.