On July 18, 1998, at 1607 eastern daylight time (edt), a Piper PA-28-140, N54R, piloted by a private pilot, was destroyed during a collision with an antenna, fence, road sign, ground and subsequent post impact fire while on initial climb out from takeoff on runway 15 (2,550' X 100' dry sod) at the Napoleon Airport, Napoleon, Michigan. Visual meteorological conditions prevailed at the time of the accident. The personal 14 CFR Part 91 flight was not operating on a flight plan. The pilot and two passengers reported no injuries. The flight departed Napoleon, Michigan, at 1605 edt. According to the pilot's written statement he said he ran the engine up to 2,500 RPM with the brakes set before beginning the takeoff. His written statement and drawing show the airplane did not lift off the runway until its takeoff roll had used up about 2/3 of the runway before it rotated for liftoff and initial climb. He said the airplane was climbing at 70 to 75 knots indicated airspeed. The pilot said the airplane "...felt sluggish..." as it passed over the departure end of the runway. The airplane's left wing struck an antenna that was attached to a livestock building shortly after the airplane's stall warning horn activated. The airplane descended under powerlines, struck a fence and road sign and the ground. The airplane's left wing separated from the fuselage and caught fire as it and the airplane collided with a highway and slid to a stop. The on-scene investigation revealed that the airplane was 100 pounds overweight at takeoff. The engine examination revealed mechanical continuity with both magnetos capable of producing sparks during hand rotation. Thumb compression was found on 3 of the 4 cylinders. The number 3 cylinder had low thumb compression. Compression on all 4 cylinders was checked using a pressure gauge. Number 1 cylinder had 76/80 pounds per square inch (psi) of pressure, number 2 cylinder had 75/80 psi, number 3 had 10/80 psi, and number 4 cylinder had 75/80 psi. Further examination of the number 3 cylinder found that the air escaped from the intake and exhaust valves when they were closed. The valve heads were below the manufacturer's minimum diameter. The valve head edge angle and seats were not ground to the manufacturer's required angle and the valve stem diameter was below the manufacturer's minimum size. Engine maintenance records showed it had been factory overhauled at tachometer time of 1,957.2 hours on August 25, 1992. These records showed it received a top overhaul on July 16, 1998, when it had a total time since overhaul of 272.3 hours. The records showed that the engine's number 1 cylinder had low compression due to "...broken compression ring and worn ring grooves." The records show that all 4 cylinders were removed from the engine. According to the records the mechanic found all cylinders "...out of limits (bore worn at top of cylinder)." The maintenance records are appended to this report.