What was found
PILOT ABORTED TAKEOFF AFTER SMOKE ENTERED COCKPIT AT HIGH RPM AND MANIFOLD PRESSURE. SMOKE WAS ENTERING COCKPIT THROUGH HEATER VENTS. SMOKE SMELLED OF OIL AND NOT ELECTRICAL RELATED. NO SMOKE WAS VISIBLE OUTSIDE OF AIRCRAFT. INSPECTION OF ENGINE SHOWED OIL DRIPPING FROM LH TURBOCHARGER ASSEMBLY. FURTHER EXAMINATION SHOWED OIL WAS PULLED THROUGH TURBOCHARGER AND INTO THE INDUCTION WHICH LEADS TO THE CROSSOVER ASSEMBLY WHICH IS WHERE HEATING AIR IS DRAWN TO HEAT THE CABIN. THE OIL SUPPLY CHECK VALVE P/N: 658746 IS IN-LINE BETWEEN OIL COOLER AND BOTH RH AND LH TURBOCHARGER ASSEMBLIES. ITS PURPOSE IS TO PREVENT OIL FROM FLOWING FROM OIL COOLER TO THE TURBOCHARGERS WHILE THE ENGINE IS SHUTDOWN. THE VALVE WAS REMOVED, INSPECTED, AND CLEANED PER 6-4.21.1 IN THE TSIO-550K STANDARD PRACTICE MAINTENANCE MANUAL . VALVE WAS REINSTALLED ON LINE FROM OIL COOLER AND OPEN FROM LINE GOING TO TURBOCHARGERS FOR 24 HOURS TO CHECK PROPER VALVE OPERATION. NO OIL WAS VISIBLE LEAKING. VALVE WAS REINSTALLED PER MAINTENANCE MANUAL WITH NO FURTHER ISSUES. IT SEEMS THE INSPECTION OF THIS VALVE IS EASILY OVERLOOKED.