What was found
DURING FUEL SYSTEM SETUP, SEVERE OIL LEAK WAS OBSERVED WHICH NECESSITATED UBRUPT SHUTDOWN. UPON FURTHER INSPECTION A HOLE WAS DISCOVERED IN TOP OF NR 4 EXHAUST ROCKER COVER. WHEN COVER WAS REMOVED IT WAS FOUND THAT ROCKER SHAFT RETAINING BOLT HAD SHEARED AT THE HEAD AND DROPPED DOWN AND WAS PUSHED OUT THROUGHT THE ROCKER COVER. CUTTING OPEN OIL FILTER FOUND SUBSTATIAL METAL INGESTION. ENGINE REMOVED FROM SERVICE. ENGINE OVERHAULED AT 827.6 HOURS AND 88 HOURS SINCE OVERHAULED CYLINDER INSTALLED.