Setting proper ignition timing is one aspect of tuning a car that can have significant impact on the performance and reliability of a car. The term ignition timing pertains to when your spark plug fires relative to the piston position. Advancing your ignition timing means that your spark plug will fire earlier in the compression stroke. Retarding your timing means that the spark plug will fire later in the compression stroke.
Proper ignition timing is all about finding the sweet spot within the safe range for ignition timing. Ignition timing that is too advanced can have dire consequences such as pinging (aka detonation or pre-ignition) where the air/fuel mixture ignites in opposition to the direction of motion of the piston, increasing cylinder pressures to dangerous levels that can result in catastrophic engine failure. These failures can be extremely forceful, sometimes even leaving holes in the engine block as parts get thrown into it. On the other hand, ignition timing that is too retarded relative to top dead center will cause poor running, poor gas mileage, and other reliability issues. You can find the correct setting for your car in your owner’s manual or on forums related to your car.
Modern cars with fuel injection and complex engine management systems tend to manage ignition timing automatically using inputs from knock sensors and other electronics (this is how some cars are able to run multiple different gasoline octane levels). Older cars, particularly those with mechanical ignition systems that use distributors tend to need the ignition timing adjusted by hand. Ignition timing is typically measured in degrees relative to top dead center of the piston.
To determine ignition timing, a timing light (also called a timing gun) is the best suited tool for the job. To use one, you hook the lead up to your #1 spark plug wire and aim the light at your crank pulley (where there is typically a timing mark next to a degree wheel on your engine block) when your engine is running. The timing light emits a burst of light every time the spark plug fires, much like a strobe light, which allows you to see how the timing mark aligns with the degree wheel which tells you your ignition timing in degrees. Once you know your timing, you can adjust it typically by rotating your distributor cap relative to your rotor to advance or retard the timing accordingly.
The Best Timing Light
Out of all the options from Innova, Craftsman, MSD, Actron and the like, the best timing light by far is the Innova 5568 Pro Timing Light. It has tons of features that really set it apart, especially when considered in combination with the extremely high quality relative to the competition. For starters, the light has multiple functions that can be read out onto the backlit display that include tachometer (rpm), advance, dwell, and voltage. The Innova Pro has a limit of 9990 rpm, which is sufficient for most vehicles including track cars.
As far as construction, the timing light comes with a housing that is resistant to shock and vibration. The tool is also covered in a molded rubber boot for protection against impact from moving parts in your engine bay. The leads are 6 feet long, which is plenty of distance to get your timing light hooked up and positioned correctly. Furthermore, the light comes with an injection molded plastic case to protect it when not in use as well as make for easier storage.
As far as value, you have to pay to play, however the outputs for this timing light provide a significant amount of additional information compared to most other timing lights out there. That said, while it’s not the cheapest, the value is still very strong because you get a lot for your money. We should mention that Innova also makes a decent and more budget friendly timing light (Innova 3551 Inductive Timing Light), which will give you the basic functionality if you want to adjust your timing on the cheap.
As far as where to buy, Amazon.com’s free shipping deal makes the shipped price pretty awesome and that is where we suggest starting. While overall we think the Innova Pro Timing Light is the best timing light around, feel free to take a look at the other options out there if you feel it doesn’t quite suit your needs by clicking here. Happy wrenching!