Iridium Spark Plugs Need a Precision Gapping Tool

by | Nov 1, 2022 | 0 comments


Setting the correct gap is one of the most important details of installing new spark plugs.

The correct gap allows the engine to fire on all cylinders, while the wrong gap will not create proper ignition or engine performance, regardless of vehicle.

Drivers should always check their vehicle’s service manual to get the correct gap information. Since gap distances are as small as a tenth of a millimeter, or four one-thousandths of an inch, it’s crucial to take extra care when checking or setting the gap in each plug. If the gap is too small, the flame kernel will not be able to properly expand. If it’s too big, the coil will need too much voltage to fire. If either of these happens, engine combustibility will be incorrect.

The Right Tool to Gap Advanced Spark Plugs  

Today’s spark plugs are precision-built parts, which means adjusting them from their original factory settings will alter their performance. This is especially true for iridium spark plugs.

Although they are designed to deliver more than 100,000 miles of reliable ignition, improper gapping can easily damage iridium plugs. To avoid this, the gap should only be checked with the right tool.

Gapping gauges have evolved just as spark plug metallurgy has. Feeler gauges or coin-style (also called ramp-style) gauges have long been used but can increase the risk of damaging the electrode. For this reason, it started to become clear that a more precise, advanced gapping tool is better suited for high-quality spark plugs.

Wire loop gauges reduce the risk of damage to the plug when used correctly. Wire loop gauges work by measuring the gap, then allowing you to gently bend the electrode with its built-in hooks if needed, and then re-measure until the gap is correct. When it comes to iridium spark plugs, the wire loop gauge is the recommended gapping tool.

Checking the plug gap is one of the most critical steps in using the right ignition products for your needs.

Autolite Iridium Ultra® Spark Plugs are the highest performance offering from Autolite® and provide the same precision and reliability of an engineered OE replacement plug. Iridium Ultra® plugs feature a laser-welded iridium finewire center electrode for optimal fuel efficiency, acceleration, and focused ignitability for long-lasting performance.

Autolite® has been focused on developing spark plugs for over 85 years. We have done the research and put in the hours to enhance the performance, durability, and ignitability of plugs for domestic and import engines.

Explore the benefits of our most advanced products like our iridium spark plugs at 


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