On July 9, 1994, at 1610 eastern daylight time, a Cessna 152, N67318, was substantially damaged following a collision with a vehicle during an emergency landing near Chamblee, Georgia. Neither the instructor pilot nor his student were injured in the accident. The aircraft was being operated under the provisions of 14 CFR Part 91 by Aviation Training Consultants of Lawrenceville, Georgia. Visual meteorological conditions existed at the time, and no flight plan had been filed for the local instructional flight. The flight departed Lawrenceville, Georgia at about 1540. The pilot stated that while in the traffic pattern on base leg, the engine lost power. An emergency landing was executed to a parking lot. During the landing, the aircraft struck a fence and a parked vehicle. Examination of the engine revealed that there was continuity of the engine drive train. The cylinder compressions, prior to staking the valves, (in pounds per square inch) were #1 38/80, #2 70/80, #3 18/80, and #4 10/80. The cylinder compressions after staking the valves, (in pounds per square inch) were #1 58/80, #2 70/80, #3 38/80, and #4 30/80. The minimum acceptable compression for the cylinders is 60/80 pounds per square inch. There was heavy carbon buildup in the cylinders, and on the pistons. The investigation determined that the engine had 2,836 hours since overhaul. Time between overhauls for the engine is 2,000 hours.