AFTER ASSEMBLING THE HOME BUILT AIRCRAFT THE CO-OWNER/PILOT INSTALLED AN ALUMINUM FITTING BETWEEN THE ENGINE CASE AND A HEAVY TRANSDUCER. THE FITTING THAT ATTACHED THE TRANSDUCER TO THE ENGINE FAILED AFTER 31 HOURS OF OPERATIONS WHILE THE AIRCRAFT WAS IN CRUISE FLIGHT OVER MOUNTAINOUS TERRAIN. THE FAILURE RESULTED IN THE LOSS OF ENGINE OIL AND THE ENGINE SEIZED. THE PILOT ATTEMPTED TO LAND THE AIRCRAFT ON A SOFT SURFACE IN MOUNTAINOUS TERRAIN. THE LANDING GEAR SANK INTO THE SOFT EARTH DURING THE LANDING ROLL AND THE AIRCRAFT NOSED OVER ON ITS BACK. A METALLURGICAL EXAMINATION OF THE FITTING DISCLOSED THAT THE FAILURE RESULTED FROM FATIGUE. THE HEAVY TRANSDUCER SHOULD HAVE BEEN MOUNTED TO THE ENGINE OR AIRFRAME WITH FLEXIBLE OIL LINES THAT WOULD ENDURED THE VIBRATIONS THAT ARE INHERENTLY ASSOCIATED WITH THE RECIPROCATING ENGINE.