On February 8, 1996, about 0845 eastern standard time, a Piper PA-28R, N55329, registered to Professional Flight Training Inc., operating as a 14 CFR Part 91 instructional flight, experienced a partial loss of engine power, and made a forced landing in the vicinity of Boca Raton, Florida. Visual meteorological conditions prevailed and an IFR flight plan was filed. The commercial pilot/certified flight instructor (CFI), and student pilot reported no injuries. The flight originated from Fort Lauderdale about 19 minutes before the accident. The CFI stated they were climbing through 4,000 feet when they heard a noise similar to a "pop" and the engine started shaking. The CFI reversed course for Fort Lauderdale and informed Miami Approach Control of his intentions. The airplane would not maintain altitude so he started flying towards Boca Raton Airport. He realized he would not make the airport and made a forced landing to a golf course. On landing roll he had to turn to the left to avoid hitting some golfers who did not move. The right wing of the airplane collided with a tree sustaining substantial damage. Examination of the engine assembly by the FAA revealed a failure of the hold down studs on the No. 3 cylinder and one hold down nut on the No. 1 cylinder. Examination of the hold down studs and nut was performed by the NTSB materials laboratory. The examination revealed that all three studs separated as a result of fatigue fracture mechanism. The fracture face on the nut contained characteristic features of a high stress fatigue separation. (See NTSB Metallurgist's Factual Report No. 96-86.) The hold down studs and nut were released to Mr. Tom Margagliano, Professional Flight Training Inc., on April 23, 1996.