For Dayco KTC1001 Engine Timing Cam Camshaft Chain Kit Replacement PartApplication For Dayco KTC1001 Engine Specification Timing belt Chain kits include everything needed to replace the timing belt and its associated parts. It connects the crankshaft to the camshaft(s), which in turn controls the opening and closing of the engine's valves. The kit generally contains the idler, belt itself, and tensioner pulleys which are necessary to maintain or decrease slack as needed, and bolts needed to secure everything in place.