On December 13, 2023, about 1730 central standard time, a Cessna T210F airplane, N6789R, was substantially damaged when it was involved in an accident near Sapulpa, Oklahoma. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The purpose of the flight was to perform an initial break-in of the engine, which had recently been overhauled. Shortly after takeoff, the engine lost all power, but the propeller continued windmilling. The pilot attempted to restore engine power but was unsuccessful. Unable to return to the airport, the pilot performed a forced landing to a road, during which the pilot maneuvered to avoid a vehicle and landed hard. During the landing roll, the right main landing gear and nose landing gear collided with a concrete curb, and the nose landing gear collapsed. The airplane sustained substantial damage to the fuselage and left wing. A postaccident examination of the engine found that the left magneto had seized and was partially separated from the engine. Impact damage to the right magneto’s p-lead was observed and the right magneto was confirmed to be grounded. Examination of the left magneto found that the internal components were heat damaged and melted. Due to the damage, further testing could not be conducted. The magneto had been rebuilt and installed on the engine during the most recent engine overhaul, which occurred about 1 hour before the accident.