Originally Posted By: maverickfhs
Thanks everyone. For some reason, maybe I am an idiot but I always prefer to use anti-seize. Though majority of my cars use chrome/silver head plugs.
Can Iridium and platinum plugs be gapped? I thought it's only true for Copper ones, isn't?
Definitely got the idea about not keeping them in a motorcycle for too long!
Regapping is possible if it's done carefully. The platinum or iridium material can take the heat and pressure, but don't do too well when they're scratched. NGK has recommendations to only use a wire gauge that's not pressed hard against the electrode and a maximum adjustment.
Quote:
https://www.ngksparkplugs.com/about-ngk/spark-plug-101/5-things-you-should-know-about-spark-plugs
In the late 1980s, when fine-wire spark plugs first appeared, installers used incorrect gap tools and procedures resulting in bent or broken-off firing electrodes. As a result, many people assumed that one cannot adjust the gap on a precious metal plug. While most NGK spark plugs are pre-gapped, there are instances where the gap requires modification. NGK recommends a wire-style or feeler gage gap tool, which can adjust the gap without prying against the center electrode. NGK also recommends adjusting the gap no more than +/- 0.008” from the preset gap.
The problem with anti-seize is that the torque specs are made with dry threads in mind. It's possible to damage the threads by overtightening and possibly have issues with the plug loosening. Not to mention the stuff getting where it shouldn't. The chrome plating on the threads is great.
I guess one of the issues with long life plugs is that they're often spec'ed because they last long for cars where it's a huge pain to access, like the back of a V engine or a boxer. So you go 10 years or 100k miles without loosening the plugs. I guess it's not so bad in an inline engine. I used to check the platinum plugs on my Integra since it was ridiculously easy to access. When I had someone install plugs on an older Integra, they charged 10 minutes labor. I figured out how easy it was to do myself. When I had someone install plugs on my WRX, they charged 2 hours labor.
And there's that "copper plug" thing again. I remember the first time I was corrected when I thought the electrode was copper. Basically all plugs these days use a copper core, but none use a copper outer electrode. That was also in the NGK answers:
Quote:
“Copper spark plugs” is a term mistakenly used for a standard material spark plug. A standard material spark plug traditionally uses a nickel-alloy outer material fused to a copper core. Almost all spark plugs use a copper core center to conduct the electricity, jump the gap, and promote heat dissipation. However, as an outer electrode material, copper would not be a good choice, as it is soft and has a low melting point (resulting in a plug that would last minutes, not miles). Nearly all NGK spark plugs, including precious metals iridium and platinum, have a copper core. When one talks in terms of nickel alloys, platinum and iridium, one is referring to its durability, or how long a spark plug will last before it needs to be replaced. However, when one talks about copper, he or she is referring to its ability to conduct electricity that is needed to fire across the gap and ignite the air-fuel mixture.
