Sparks Fly...

Automotive Tip of the Week: When it comes to sparkplugs it is more or less all marketing. The biggest difference between spark plugs really is longevity. You are NOT going to get more horsepower by running a platinum or iridium plug over a copper plug. What you will get is more life. Platinum and Iridium plugs are typically rated for 60-100K miles versus copper usually is rated for around 30-50K. The rating really revolves around the fact that the spark actually eats away a little bit of metal every time the spark makes the gap jump. As this happens the gap between the electrode and the ground point (the arch) gradually opens up and becomes too large. This eventually can result in performance problems as the coil may not be able to get a spark to make the gap jump and then you get misfires and poor engine performance. So the decision you need to make is price/cost. If you change plugs yourself and it is easy to do on your car (like on most 4 cylinder cars) you can save a fair amount of money changing plugs yourself with copper plugs running under 2 dollars many times. Iridium plugs can be north of 20 dollars a plug. So If you assume 50k versus 100K intervals you see the Iridium or Platinum plugs don’t save you much. However, if you have a mechanic change the plug as soon as they charge you the 80 dollars in shop labor, there is no difference in cost over the interval and this is why many cars come from the factory with platinum or iridium as it cuts down warranty service costs for the dealer (and provides any easy upsell item if they want to tell you they think plugs need changing!). There are a lot of other items with plugs to talk about including multi-point plugs, heat ranges, “reading” a plug etc. But I’ll leave that for another time and touch on just one other point. Iridium and Platinum plugs are also referred to as fine-wire plugs because of how small the tips of them are. There are some major downsides to this technology. First, it fouls out MUCH easier. So if you are running a customized car (with added turbo or modified injectors etc), you have a car that burns a lot of oil or coolant, has other issues, or is simply older and doesn’t use precise fuel injection you will potentially have a LOT of problems with a fine-wire plug. Copper standard plugs will be much more resistant to those issues. Therefore, stay away from fine-wire on any car that isn’t running perfectly as you’ll likely compound the issues with poor running. The second major drawback is the fine tips are more susceptible to pre-ignition if the heat range of the plug is not correct or again you have a defect in the motor causing it to run poorly or is being overheated. I personally never run fine-wire plugs in any of my cars for those reasons (cost and reliability) as well as others regardless of how high performance the car is or isn’t. Happy Motoring!