IN THE TRAFFIC PATTERN DURING AN AIRSHOW THE ENGINE BEGAN TO RUN ROUGH AND THE PILOT DETECTED A HOT OIL SMELL. SHORTLY THEREAFTER, THE ENGINE SEIZED AND THE PILOT LANDED SHORT OF THE RUNWAY IN A GRADED CONSTRUCTION AREA. AN FAA INSPECTOR MONITORING THE AIRSHOW ARRIVED IMMEDIATELY AFTER THE ACCIDENT AND FOUND THE PROPER QUANTITY OF OIL IN THE TANK AND NOTED THE OIL WAS COLD TO THE TOUCH. DETAILED EXAMINATION OF THE ENGINE REVEALED EXTENSIVE HEAT SIGNATURES, GALLING OF THE FRONT BEARING AND METAL PARTICLES DISTRIBUTED IN THE OIL SUMP; ALL CHARACTERISTICS OF OIL STARVATION. THE OIL PASSAGES AND OIL PUMP WERE NORMAL. EXAMINATION OF THE OIL TANK REVEALED THAT IT WAS EQUIPPED WITH AN OIL SHUT OFF VALVE. THE VALVE IS NORMALLY TURNED OFF AFTER EVERY FLIGHT. THE PILOT STATED THAT HE IS SURE HE TURNED THE VALVE ON PRIOR TO THE FLIGHT, HOWEVER, THE POSITION OF THE VALVE WAS NOT DOCUMENTED AT THE ACCIDENT SITE AND THE PRE IMPACT POSITION COULD NOT BE ESTABLISHED WITH CERTAINTY.