Knowing the different types of spark plugs and understand them is quite useful for anyone who deals with engines. In most cases, experts explain about four types of spark plugs. You may or may not have come across a spark plug explained below:
Copper Spark Plugs
In this spark plug, the centre electrode is a 2.5mm-diameter nickel alloy but has a solid copper core. Of all the other spark plugs, the diameter of the electrode in this spark plug is the biggest. Since nickel is actually softer than platinum or iridium, the other metals used, the sharp firing end tends to wear out quickly in this plug.
Copper spark plugs are considered to be high-performance spark plugs, but they don’t last long like others. There exist some late-model high-performance engines that use specifically copper spark plugs. Please note copper spark plugs are ideal mostly for older engine models (the pre-80s) which come with low voltage distributor-based ignition systems. You’re advised not to use copper plugs in high-energy distributor systems (DIS) or coil-on-plug (COP) ignition systems as they will wear out very quickly. Do not upgrade to other spark plugs if your owner’s manual recommends a copper spark plug.
Single Platinum Spark Plugs
Similar to a copper plug in style this spark plug has a platinum disc fitted to the centre electrodes tip. With platinum, which is harder than nickel alloy, this plug holds it’s sharp end for quite long, usually up to 100,000 miles. Since platinum spark plugs can run a bit hotter, they’re able to prevent spark plug deposit buildup as well as fouling. For those with new engine models that come with electronic distributor-based ignition systems, then the platinum spark plugs are the plugs for you.
While you should not downgrade to copper spark plugs if your owner’s manual calls for platinum spark plugs, you can upgrade to double spark plugs or iridium spark plugs.
Double Platinum Spark plugs
Considered twice as good as the single platinum plugs, these are designed for “waste spark” DIS. Double platinum spark plugs are made to handle the reverse spark in a waste spark system. The plugs feature two platinum discs, one on the centre and another welded to their side electrode. Since both the discs remain sharp, the sparks fly easily in both directions without leading to rapid electrode wear.
If your owner’s manual recommends double platinum spark plugs, you should never downgrade to single platinum spark plugs but can look for an iridium/platinum combination plug.
Iridium Spark Plugs
These are regarded as the best spark plugs among all types. Their longevity is the most impressive. Iridium is harder than platinum, and these plugs have been found to last around 25% longer than comparable platinum plugs. Manufacturers may reduce the diameter of the centre electrode to as little as .4mm to save money, but this also increases firing efficiency. Iridium Spark plugs are usually made for Coil-on-plug ignition systems by many carmakers. An iridium/platinum combination spark plug is also ideal for COP ignition systems. Always stick to iridium spark plugs if your owner’s manual recommends those.