Did you know that NGK iridium spark plugs never have to be gapped? They come pre-gapped. If you try to gap them, you will ruin the coating and the plug. Also, if you drop a plug while installing it and the gap closes, that plug is trash.
Those of us involved in modifying BMW's commonly gap / regap iridium plugs (adjusting the ground electrode w/out contacting the center electrode). I've even cleaned the iridium electrodes in a pinch without issue which is 6 times harder and 8 times stronger than platinum. Would not recommend using this type of gapping tool on iridium as you risk pushing the center electrode down into the plug body making it more difficult for a flush / square gapping.
I should have clarified my statement. Both the ground and center electrodes are coated for double iridium plugs. For single iridium plugs only the center electrode is iridium. While it is possible to gap an iridium plug, extreme care must be taken. Applying pressure or a prying force to the fine wire center electrode or insulator can damage it.
Appreciate the info! So if I'm gapping an irridium plug and the tip rubs slightly against the metal on the gapper, it will remove the coating?
Not necessarily. Just be careful. There are two tools that you can buy on Amazon to properly gap a spark plug. Check out this video.
An interesting fact about pure iridium is that it is a rare element that is found in nature with platinum and other platinum group metals. Iridium generally is produced commercially along with the other platinum metals as a by-product of nickel or copper production. The top producers of this rare element are South Africa, Russia, Canada and the U.S. Also, it is found in meteorites.
