Ignition timing is used to ignite the fuel in an internal combustion engine at a particular time in an effort to burn as much of the fuel as possible in the power stroke. Complete combustion of the fuel would be ideal, however, given the inefficiency of the engine, this is very difficult. Timing is adjusted to maximize the fuel burn as much as possible. Fuel takes a certain amount of time to burn. As the engine rpm increases the time the fuel remains in the engine decreases exponentially, thus ignition timing is advanced to allow more time for combustion.
Mark the timing mark on the harmonic balancer with the white marker to make it more visible for the timing light. Look for the long straight line on the balancer and mark this. Look at the timing plate on the driver’s side of the timing chain cover. Notice that it has a V cut in the center of the marker plate — this is top dead center on the compression stroke. The numbers to the left of the V, looking at the engine from the front, are degrees of advance or how many degrees before top dead center. The numbers to the right of the V are degrees after top dead center. You always want to have the timing advanced or before top dead center.