How To Choose The Best Spark Plugs

The metal used to create the center electrode can have a big impact on the performance of the plug. Many times manufacturers will use small amounts of precious metals to improve the life as well as the firing ability of a plug. These metals are often expensive, so cheaper designs may only use enough to make the claim of the particular type of electrode. Some metals are selected for long life, while others are selected for a superior ability to conduct electricity.




Platinumis one of the most common metals used in high performance or long life plugs. Platinum has a high melting point that can prevent wear of the electrodes. Platinum can also be used on fine wire tips. The amount of platinum used in the plug can greatly influence its price. The best spark plugs will have more platinum than is found in a $2 platinum plug.

Iridium, another precious metal offers six times the hardness and eight times the strength of platinum. It melts at a temperature that is 1200 degrees higher than platinum and is a better conductor of electricity. Use of iridium allows the manufacturer to create a very fine-wire center electrode. Use of iridium helps to create smaller center electrodes in an ultra-long life plug. The problem with pure iridium is that it oxidizes at high temperatures and it is expensive. Most manufacturers choose to create alloys with other precious metals, including Yttria, Platinum or Rhodium. These alloys can combine the strengths of all the metals included. Once again, the cost can be an indicator of the amount of iridium included in the e