On March 26, 2019, about 1730 central daylight time, a Cessna 140 airplane, N76268, nosed over during a forced landing near the Newton City/County Airport (EWK), near Newton, Kansas, following a loss of engine power. The private pilot was uninjured. The airplane sustained substantial wing and empennage damage. The airplane was registered to and operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Day visual meteorological conditions prevailed in the area about the time of the accident, and the flight was not operated on a flight plan. The local flight originated from EWK. This was the first flight after an annual inspection of the airplane. According to the pilot's accident report, the engine run up check was conducted, and the magnetos and carburetor heat were "good." During the takeoff, the climb out engine power was "good." On the turn to downwind, the pilot noticed a slight loss of engine power below "normal." He checked the throttle position and continued the downwind leg of the flight. The pilot considered a crosswind landing on runway 8/26. However, he felt he had engine power to make a short 180° approach to runway 17. During the turn to final, the engine power dropped further, it "clattered" about 3-4 seconds, and subsequently stopped. The pilot stated that the only option was to land straight ahead in a field to the north of runway 17. A Federal Aviation Administration inspector examined the engine and found that he could only rotate the propeller through 270° of rotation. The engine was subsequently removed from the airplane, crated, and shipped to Continental Motors for a disassembly inspection. During disassembly, the No. 1 connecting rod end was found separated from its crankshaft journal and the rod end exhibited discoloration consistent with lubrication distress. Liberated sections of the No. 1 connecting rod bearing were found in the oil sump and those sections exhibited discoloration consistent with lubrication distress. The oil transfer tube orifice for the No. 1 connecting rod bearing was smeared over with migrated connecting rod journal material. The migrated and smeared metal was drilled through to see if any debris was present. Only metallic particles were present that were attracted by a magnet. The remaining oil transfer tube orifices and oil galleys were not obstructed. The remaining three connecting rods remained attached to the crankshaft. However, the connecting rod ends, and rod bearings all exhibited discoloration consistent with lubrication distress. Scoring consistent with hard particle passage was observed within the oil pump housing. The camshaft was fractured in the area abeam the separated connecting rod and the camshaft fractures surfaces appeared grainy and dull consistent with overload. The oil filter, hand dated March 22, 2019, was cut open and had one spot of dark colored debris and no other debris found within the filter pleats. The oil suction pickup tube was disassembled and it did not contain any debris.