On May 24, 1993, about 0930 hours Pacific daylight time, a Cessna 182P, N642WR, sustained substantial damage following the collapse of its nosegear and subsequent nose over during landing roll about 5 miles north of Reno, Nevada. The nosegear collapse and nose over came at the culmination of a forced landing which was precipitated by an engine problem. The certificated private pilot was not injured. The cross country, personal flight was being operated by the pilot/owner. The flight originated in Sunriver, Oregon, about 0800 hours and was destined for Reno. Visual meteorological conditions prevailed and a flight plan was not filed. In his oral statement, the pilot said he was at cruise flight near Reno when he heard a loud noise which came from the vicinity of the airplane's engine. He said the engine area also began to smoke. He reported that he secured the engine and entered a power off forced landing. The airplane landed on rough and uneven terrain. He said the nose gear collapsed during landing roll and the airplane nosed over. An FAA airworthiness inspector examined the airplane after the accident. The inspector said the airplane's alternator "seized" resulting in a frozen pulley on the alternator. The drive belt then broke causing a loud noise. An airframe and powerplant mechanic, who the pilot said routinely performed maintenance on the airplane, was interviewed. He said the airplane's engine and engine accessories were replaced with overhauled parts about 25 flight hours prior to the accident. He said that the alternator was examined after the accident for the pilot's insurer. During the examination, it was noted that a bearing had been installed backward during the overhaul process.