At 0854 central time, a Bellanca 14-13-2 was damaged when it landed short of runway 23 at Quad City International Airport. The pilot was not injured. The pilot said he departed Moline for Brodhead, Wisc., but the oil pressure began fluctuating. He decided to return to Moline. During the approach, he reduced power to lower the flaps and the engine did not respond when he reapplied power.