What was found
ON THE 6TH RUN FOR GROUND ADJUSTMENTS, OIL PRESSURE DROPPED TO 30 THEN 10 PSI AND ENGINE SECURED. REPEATED ATTEMPTS TO PRIME OIL SYSTEM, COULD NOT GET OIL PRESSURE UP. PUMP WAS REMOVED AND INSPECTED WITH NO OBVIOUS DEFECTS. OIL PAN WAS REMOVED AND PICK-UP TUBE INSPECTED WITH NO DEFECTS. ONLY DEFECT NOTED WAS THAT OIL PUMP WAS PROBABLY INCORRECTLY SILK THREADED ALLOWING AIR TO BE SUCKED INTO SYSTEM AROUND ORIFICE. AFTER REINSTALLATION OF COMPONENTS, NO FURTHER PROBLEMS ENCOUNTERED AND ACFT FLOWN WITH NO PROBLEMS.