Timing belt for a Daewoo leganza is off?

If you mean the belt fell off the gears while the engine was running, you will have to replace the cylinder head. This is a zero clearance DOHC motor. When timing jumps, slips, or belt slips or breaks, you WILL have broken valves. Be prepared for a lengthy search---even for a salvaged head---Daewoo parts are becoming scarcer by the day---good luck