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What Is Engine Ignition Timing?
Engine ignition timing is the number of degrees before top dead center that the spark from the distributor is sent to the #1 cylinder in your vehicle’s engine. Proper timing is important for optimum engine performance as the fuel that is in the cylinder is ignited at the precise time to push down on the piston. Incorrect timing will cause low power, increased engine temperatures, and even engine damage due to pre-ignition or detonation from igniting fuel too soon or too late. An engine timing light helps ensure your engine is providing spark at the correct point in the combustion cycle.
How Does A Timing Light Work And How Do You Read It?
A timing light works by emitting a flash of light every time the #1 spark plug wire receives voltage from the ignition distributor through the attached inductor signal clamp connection. When pointed at a harmonic balancer, the strobing effect the gun gives off using a bright bulb illuminates the top dead center groove on the balancer. The groove will appear next to the marks on the timing pointer, typically bolted to the timing chain cover. This provides the engine timing in degrees for the engine at the RPMs the timing light is used. Adjustments can then be made to timing by rotating the distributor to optimize the timing advance.
How To Hook Up And Use A Timing Light
Using a timing light is fairly easy. There are three connections: the positive and negative clamps and an inductive pickup / signal clamp. The positive and negative alligator clamps connect to the vehicle’s matching battery terminals and the pickup / lead wire clamps around the #1 spark plug wire. Care must be taken not to place any of the timing light wires in the way of moving belts, fans, pulleys, parts, or hot surfaces like the exhaust. The engine is then started and the correct idle RPM needs to be set. To use the timing light, a trigger or button is pressed for it to begin flashing. When pointed at the harmonic balancer, you will see the cut groove appear as it is in the same spot as when the light flashes onto it. You then line up the groove with the timing pointer that is on the timing cover to the correct degrees for your vehicle’s engine (you need to research and confirm base / idle timing) by rotating the ignition distributor.
What Is The Best Timing Light?
There are many types of timing lights to choose from. Depending on your needs, you can choose from the most basic type that just gives off the strobe light to provide the base timing, or you can choose a digital readout that provides the engine RPMS, and allows you to dial in the timing you want for both base and total timing. Let’s explore the options:
Self-Powered
This type of timing light doesn’t use connections to the vehicle’s battery for power. Instead it uses batteries (example, D-Cell) for power. This means that there is only one connection: the inductive pickup to attach to the #1 spark plug wire. This makes the timing light a little less cumbersome to hook up and safer from wires getting burned or caught in moving parts under the hood. This type of timing light is also usually the lowest cost version due to less parts. However, as a trade-off, the batteries need to be in optimum condition in order for the timing light to properly work and give an accurate reading. Self-powered timing lights are primarily designed to help adjust and confirm base (at idle) timing.
Standard
This type of timing light uses a positive and negative cable connection to the vehicle’s battery for power. It also uses the inductive pickup clamp to connect to the #1 spark plug wire for a signal. Either a trigger or button activates the timing light. This type of timing light is designed to help adjust and confirm base (at idle) timing. It is considered an entry-level type of timing light and is also affordable.
Advance Timing
The mechanical advance timing light uses a positive and negative connection to the vehicle’s battery for power. It also uses the inductive pickup clamp to connect to the #1 spark plug wire for a signal. Either a trigger or button activates the timing light. This type of timing light has an additional feature. There is a knob on the timing light that allows you to dial in to the exact degrees of timing that you want to achieve. Once you set the dial to the “target” timing degrees, you will then adjust the distributor until the timing groove on the balancer lines up with zero degrees on the engine timing pointer. You can also use this type of timing light to find out how many degrees the engine is currently set at. Simply turn the knob on the timing light until the groove on the harmonic balancer lines up with zero degrees on the engine timing pointer. Then look at the timing light knob and note the number of degrees the knob is pointed towards. This is what the timing is currently at on your engine at the RPMs it is running at. This function is designed to work for both base (idle) timing as well as total timing (base plus mechanical advance, typically at 2500 rpms or higher).
Digital Advance Timing
This is the “top of the line” timing light. Like other timing lights, digital advance timing lights use a positive and negative connection to the vehicle’s battery for power. It also uses the inductive pickup clamp to connect to the #1 spark plug wire for a signal. Either a trigger or button activates the timing light. There are a few added features to this timing light. The first is that it has a backlit LED digital display for better visibility while under the hood. This display provides a digital tachometer reading of the engine RPMs. This added feature allows you to see everything on one screen and monitor degrees of advance at any given rpm you choose. It also displays the timing advance in degrees digitally. Instead of a knob on the timing light there are “up” and “down” buttons that allows you to dial in to the exact degrees of timing that you want to achieve. Once you set the “target” timing degrees, you will then adjust the distributor until the timing groove on the balancer lines up with zero degrees on the engine timing pointer. You can also use this type of timing light to find out how many degrees the engine is currently set at. Simply press the “up” or “down” buttons on the timing light until the groove on the harmonic balancer lines up with zero degrees on the engine timing pointer. Then look at the timing light display and note what degrees are shown. This is what the timing is currently at on your engine. This function is designed to work for both base (idle) timing as well as total timing (base plus mechanical advance). This type of timing light helps provide precise and accurate timing with ease. However, this is the most expensive type of timing light.
