There’s more to timing lights too. In truth, many enthusiasts (and believe it or not, that includes many of us in the high performance community) hook up timing lights incorrectly. It sounds bizarre but it isn't. Often, a convoluted header configuration coupled with a tight engine compartment will only allow one easy light installation. Trouble is, that installation might not be correct. If the timing light is setup incorrectly, the timing marks you are watching could be a mile (and more than a few degrees) off. According to MSD, when setting up your timing light, there are several things to consider:

• Be absolutely certain that the positive and negative clips are correctly attached to the battery or power source. Never use the coil as a source of power! Be certain that the pair of timing light power cables is not in contact or close to any of the spark plug wires.

• When connecting the trigger clamp to the number one cylinder, be absolutely positive that the clamp does not come in contact with any other spark plug wires. If contact is made or if the trigger is close to any other wires, there is a good chance that a false triggering will occur. Additionally, it is always a good idea to further separate the number one cylinder wire lead from any other cylinder wires. Stray signals or spark crossover will not influence the timing light if this practice is always followed.

• Some timing lights require the trigger clamp to be mounted in a specific direction on the spark plug wire. Be absolutely positive that your clamp is mounted with the jaws pointing in the proper direction. In the event that the clamp is installed upside down (and it's very easy to do), the timing will appear retarded.

As you can easily see, there's much more to timing lights than simply hooking up the power cables and clamping the inductive pickup over number one cylinder. Who knows, there's a chance you could find some serious power lurking in your engine. And only because you were fooled by a faulty timing light.

Both timing light power cables should be affixed to the battery. In the event that your car has a trunk mount battery or pair of batteries, add a power junction block to an accessible location in the engine compartment. Never use the coil as a source of timing light power.	Number One ignition wire must be well separated from the other wires on the engine. Spark cross over from other wires can easily influence timing light performance.
Be positive that the inductive pickup clamp is correctly oriented. Virtually all timing light clamps have arrows or instructions which indicate the proper orientation. If the clamp is installed backward, then the engine timing will appear retarded.	Never allow the trigger clamp to come in contact with any of the other spark plug wires. If the trigger clamp or the wire that connects to the clamp are close to spark plug wires other than number one, they can influence the timing. Similarly, the power wires can pickup false signals if they run too close to the primary ignition wires.

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