How to set the timing with a timing light

If you are referring to the ignition timing, the you connect the timing light into the no 1 spark plug lead. Start the engine and shine the light - which should be flashing - at the front of the engine onto the harmonic balancer. You should be able to see the timing mark on the harmonic balancer, and the scale on the engine you align it to. It may help to mark the harmonic balancer with a small dot of white paint to make it more visible. Adjust the distributor so that the timing mark on the harmonic balancer aligns with the timing mark on the block that the manual tells you to use. Make sure that the idle speed is correct first. However if you have not removed the distributor, then the ignition timing should still be OK. If you are referring to the timing of the camshafts and gears, then you do not use a timing light. Most vehicles have special tools that are installed onto the camshafts and crankshaft which lock them into the correct position so that the timing is correct. If you have replaced all these parts and do not know how to set the timing of them, get help from a mechanic otherwise you will break you engine when you try to start it.