What was found
AFTER TAKEOFF, WHILE CLIMBING OUT OF 6000 FT, RED MASTER WARNING LIGHT ILLUMINATED AND LOW OIL PRESS LT LIGHT WAS FLASHING. LT OIL PRESS GAUGE WAS CHECKED AND INDICATED 0 PSI. EMERGENCY CHECKLIST ACCOMPLISHED AND LT ENGINE WAS SHUTDOWN. ENGINE PERFORMED INITIAL TROUBLESHOOTING. INSPECTED OIL FILTER AND OIL FILTER AND COLD START VALE WITH NO DEFECTS IAW ENGINE MM 79-20. (REF SQK 1.4) REMOVED LT ENGINE OIL PUMP IAW ENGINE MM 79-20-02. (REF. SQWK 1.10) ENGINE STILL HAS NO OIL PRESSURE; ENGINE IS TO BE CHANGED. REMOVED ENGINE AND INSTALLED A REPAIRED ENGINE IAW ENGINE MM 71-00-03. AND THE MM 71-00-03. REF SQK 1.41 ALL LEAK AND OPERATIONAL CHECKS OK.