On April 23, 2003, at 1230 Pacific daylight time, a Cessna 175B, N8159T, registered to and operated by the pilot as a 14 CFR Part 91 personal flight, experienced a loss of engine power followed by a forced landing on a county road located 10 miles southeast of Bonanza, Oregon. During the landing roll, the aircraft collided with a pole. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was substantially damaged. The commercial pilot was not injured, however, the passenger received minor injuries. The flight originated from a private airstrip in Wellington, Nevada, about three hours prior to the accident. During a telephone interview, and subsequent written statement, the pilot reported that while in cruise flight at 10,500 feet, the engine made a loud sound, followed by a partial loss of engine power. Shortly thereafter, smoke started coming in the cockpit and the engine lost complete power. The pilot initiated a forced landing to a county road. During the landing roll, the left wing collided with a power pole. The airplane spun around, the nose gear collapsed and the airplane subsequently nosed over. Inspection of the engine revealed a large hole in the crankcase between the numbers 1 and 2 cylinders. Portions of the numbers 1 and 2 connecting rods were recovered. Visual examination of pistons 1 and 2 found that the pistons were intact, however, several areas of the skirts had been broken off. The upper portions of both the 1 and 2 connecting rods were still attached to their respective piston pins. The crankshaft and counterweights were intact. The number 1 connecting rod bearing journal was deeply scored, blue in color and dry. The number 2 connecting rod bearing journal was bright, shiny and wet with oil. Portions of the number 1 main bearing insert could be observed between the number 1 crank cheek and the number 1 main bearing saddle. The numbers 1 and 2 crank cheeks were blue in color and dry. Portions of the number 1 connecting rod were blue in color and dry. Portions of the number 2 connecting rod were bright and shiny and wet with oil. The number 1 connecting rod cap had a portion of one bolt still present in the cap. The fracture area of the bolt was necked down in diameter and the bolt was blue in color. A matching portion of a bolt with the nut attached was recovered and noted that the fracture area was also necked down in diameter. The pilot was unable to locate the maintenance logbooks and assumed that they were destroyed in a fire that was on the pilot's property in February 2002. The pilot reported that the aircraft had not been maintained in accordance with an annual inspection for some time, as he had not been flying the aircraft since about 1997, when the engine was top overhauled. The pilot estimated approximately 80 to 90 hours had been accumulated on the engine since the top overhaul. The pilot estimated approximately 830 hours since the engine underwent a major overhaul.