Why You Should Always Measure Your Spark Plugs Before You Put Them In Your Car

Calibration of spark plugs is a procedure that is performed when they are taken out of their packaging, just before they are placed in the vehicle. For this procedure, it is important to have a special device known as a candle gauge.

The function of spark plugs in any internal combustion engine is essential. In fact, if the spark plugs aren't working properly, it's very likely that your car won't be able to run at all.

Spark plugs are responsible for igniting the mixture of fuel and oxygen in the cylinders by means of a spark in an ignition assisted internal combustion engine.

For a spark plug to work properly, it must be properly calibrated before installation. In other words, the distance between the ground electrode and the center electrode must be perfectly adjusted. 

What is spark plug calibration?

Calibration of spark plugs is a simple but mandatory procedure for each replacement of spark plugs carried out on a car, both during preventive maintenance and when they fail.

Spark plug calibration is a procedure that is performed to obtain the ideal gap in the spark plug electrodes, thereby creating the ideal electrical arc that the manufacturer has planned for that particular engine. 

What gap should my spark plugs be?

For most racing applications, clearance should typically be between 0.020 and 0.040 inches. Most engine manufacturers set it to 0.035 inches. Factors such as the type of ignition used, cylinder heads, fuel, and even timing can affect the distance that is optimal for you.

What happens if you miscalibrate spark plugs?

Too small a gap can give too little spark to complete the combustion process inside the engine; too much clearance can cause the spark plug to not fire properly, resulting in a misfire or vehicle misfire, especially at high speeds.

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