What is Ignition Advance Angle?
2 Answers
Ignition advance angle refers to the angle through which the crankshaft rotates from the moment of ignition until the piston reaches the top dead center of compression. The functions of ignition advance angle are: 1. To ensure the effective utilization of the energy generated by the combustible mixture; 2. To improve the engine's output power. The adjustment method for ignition advance angle is: 1. Check whether the platinum contacts have signs of burning; 2. Remove the secondary chamber vacuum hose from the vacuum advance compensation device, block the two ports connected to the hose, and let the engine idle; 3. Use an ignition timing light to check the ignition advance angle; 4. When rotating the distributor housing counterclockwise, the ignition advance angle will increase; 5. When rotating the distributor housing clockwise, the ignition advance angle will decrease.
I want to use the experience of an old mechanic to explain ignition timing advance. This refers to the angle by which the spark plug fires ahead of time, meaning the spark plug ignites just before the compression stroke ends. Why advance it? Because after the air-fuel mixture ignites, the flame needs time to spread and burn. By the time the piston reaches top dead center and starts descending, the combustion should be just complete, ensuring optimal power output. If ignition is too late, the piston is already moving down, leading to incomplete combustion, wasted fuel, and black smoke. Too early, and it can cause knocking, which sounds like wood knocking and can damage the piston or cylinder head over time. Most modern cars use computer-controlled timing that adjusts automatically based on engine speed and load, while older cars require manual adjustment of the distributor. Remember, setting it just right improves fuel efficiency and driving smoothness, especially noticeable at high speeds. If unsure, don’t tamper with it—consult a professional. This knowledge is very helpful for car maintenance.
