The engine is what supplies the required power to all parts of a running classic car. Even when the required amount of fuel and air is supplied to the engine, it is crucial that the air-fuel mixture be ignited at the right time to get the most power out of it. This is where the engine ignition timing gains importance. The ignition spark should be generated at a precise time so that the air-fuel mixture burns completely. This post explains the significance of engine ignition timing on the performance of the car engine, and details what can go wrong in a vehicle with an incorrect ignition timing.
What Ignition Timing Does
The engine ignition timing sets the right point at which the air-fuel mixture in the engine’s combustion chamber is ignited. The timing is measured in degrees before or after the piston reaches the top dead center (TDC). If the ignition system is set to ignite the fuel exactly when the piston reaches the TDC, the ignition timing is said to be 0 degrees. If the ignition system is set to produce the spark before the piston reaches the TDC, the ignition timing is said to be advanced. To get the optimal power for various engine speeds, the ignition timing should be altered accordingly. Generally, the ignition timing is advanced to get the maximum power from the engine.
Typically, the spark is fired 10-30 degrees before the piston reaches the top dead center (TDC). The air-fuel mixture burns at the same rate, irrespective of the engine speed. The faster the engine runs, the more will be the ignition timing advance, to achieve maximum pressure at the same point in the engine cycle. Older vehicles required the ignition timing to be set manually. They used either vacuum advances or centrifugal advances to set the right advance timing. In some vehicles, the ignition timing will be retarded. This is usually done where reducing the emissions takes priority over producing more power.
The right time to ignite the fuel is affected by various factors such as the engine displacement, octane rating of the fuel, engine compression ratio, condition of the spark plugs and intake pressure of the engine. Typically, the ignition timing is adjusted when any changes or upgrades are made to the engine.
Ignition Advancing vs. Ignition Retarding
Engine ignition timing is measured in degrees of a crankshaft rotation before top dead center (BDTC). Spark plugs need to fire at the right time, which can be achieved by advancing or retarding the timing of the engine.
Timing advance means that the spark plugs are firing earlier in the compression stroke, farther from TDC. The air and fuel mixture in the combustion chamber doesn’t burn right away. Ignition timing advancing might be needed to allow time to get everything ignited.
The major benefit to advancing the timing of a vehicle’s ignition is increasing the horsepower of an engine. Advancing the ignition timing helps raise the high-end power while reducing the low end. It also helps get the spark past the ignition delay and run at peak power.
Retard Timing causes the spark plug to fire later in the compression stroke. The effects of retarding ignition timing include reducing engine detonation, which is combustion inside the cylinders after the spark plug fires. This is also known as engine knocking.
When it comes to turbocharged or supercharged engines that are running at higher levels of pressure, retarding the timing of an engine can be more beneficial. Retarding the timing on these kinds of engines helps compensate for denser air and fuel mixtures and allows them to run more efficiently.
Effects of Wrong Ignition Timing
Improper ignition timing can cause several engine problems such as knocking or pinging, hard starting, overheating, increased fuel consumption and reduced power output.
Knocking or Pinging
This is one of the common symptoms in an engine. Knocking occurs when the ignition timing is set before the ideal advance timing. In these cases, the spark plugs produces the spark when the engine is still in its compression phase, resulting in improper burning of the air-fuel mixture. To prevent engine knocking, modern cars use knock sensors.
Low Power
Ignition timing that is retarded too far can result in the spark plug igniting the mixture too late. This can reduce the power of your engine.
Hard Starting
This can be either due to an advanced or delayed ignition. In both cases, the engine will not produce the optimal power, causing the vehicle to experience difficulty while starting.
Overheating
Overheating is one of the symptoms that the air-fuel mixture was ignited way before the power stroke. This causes the engine to generate more heat than usual.
All in all, a wrong ignition timing will bring down the engine power and efficiency. The air-fuel mixture that is fired anytime other than at the ideal time will result in improper combustion. This will also cause the fuel economy to decrease.
Finally
There are a lot of moving parts in a car’s engine. From the crankshaft and camshaft to the pistons, rods, and pulleys, all of these components are moving quickly and at specific times so things function properly.
During this process, your car’s engine utilizes four distinct piston strokes in order to run effectively. There are four steps involved: intake, compression, power and exhaust. A car’s engine ignition timing comes into play during the compression stroke. Ignition timing controls when the spark plug fires during this process.
Ignition timing is an important process that plays a big role in the performance of an engine. Considering this, it makes sense that there would be ways to affect the ignition timing process to increase vehicle performance. The best way to maximize engine performance is through advancing or retarding ignition timing.
Remember it’s important to consult with your owner’s manual for the details of your specific engine before determining what can be adjusted with the ignition timing.
