As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHORTLY AFTER TAKEOFF, WHILE CLIMBING THROUGH ABOUT 3000 FT, ENGINE LOST ABOUT 200 - 300 RPM MOMENTARILY AND THEN RECOVERED. IT DID THIS 2 TIMES AND THEN WENT BACK TO NORMAL. NOT LONG AFTER THIS NOTICED THAT THE OIL PRESSURE HAD DIPPED INTO THE YELLOW. MX CHECKED THE OIL SCREEN AND FOUND METAL AND PROCEEDED TO THE OIL FILTER AND FOUND MORE METAL. PERFORMED COMPRESSION TEST AND FOUND THE NR 4 CYLINDER TO HAVE VERY LOW COMPRESSION. REMOVED NR4 CYLINDER AND FOUND COMPRESSION RINGS BROKEN.