Yes, it is possible to repair a crack in cast iron without welding, using a technique called cold stitching or metal stitching. This method involves drilling holes on either side of the crack and placing metal stitching pins or keys through the holes. The pins are then locked in place using epoxy or a high-strength adhesive. Metal stitching reinforces the cracked structure and prevents further propagation of the crack. However, it is important to note that cold stitching is typically used for non-loaded or lightly loaded cast iron parts. For critical or heavily loaded components, welding is generally the preferred method of repair.