Changing ignition timing can be a very basic tuning tool. There are limitations as to how much timing an engine can handle and understanding the changes that take place will make you a better Tuner. There is a simple rule that you should always keep in mind when adjusting engine timing.
Advancing the timing will lean out the A/F ratio of an engine. Advancing the timing starts the burning process sooner in the Fire cycle. Advancing the timing can show an increase in Torque and Horse Power numbers at a lower RPM and at times carry the gains throughout the RPM range. A great deal of care must be taken when advancing timing of a race engine. High Compression engines have a narrow window on timing. To much timing can cause detonation and cause severe engine damage.
While Retarding the engine timing can and will richen your tune-up, it very well be costing you some Horse Power numbers if the timing is set back too far. Tuning to find the “Sweet Spot” for a race engine and its timing can take some time. Trying to find the proper number on the track can be tricky and at time impossible to achieve. Working on the Dyno is the best and safest way to fine proper timing of an engine.
A more Advanced Tuner uses engine Timing to compensate for humidity at the track, or adjust timing for relative altitude at a given race track. The adjusting of timing can go hand and hand with changing jets or air bleeds on a carb. Once again a great deal of caution must be taken before a tuner makes big changes at a racetrack or on the Dyno.
Rotor Phasing goes hand in hand with timing changes. Race engines that use Crank Trigger ignition systems change engine timing at the front of the engine. A tuner MUST phase the rotor after changing timing. A race engine that uses an after market Multi Spark Ignition system will require a quality timing light that can handle and read a multi spark.