I have always attributed the rapid decline of my spark plugs to being just a penalty of forced induction, but reading in a service manual to fix a Nissan truck, I found the following quote on Iridium spark plugs:

"Note: The manufacturer recommends against checking the spark plug gap, as the Palladium or Iridium coating could be scraped off, thereby greatly reducing the life of the spark plug."

I have always set my own plug gap, quite a bit tighter than stock.

/and my coils fire hotter than stock....

 

Interesting.............I usually check mine as installing and am careful, but interesting.
Given that I change them every 12k miles anyway(and not boosted).......not sure I would see the results of this particular degradation......should it be legit.

 

iridium is a very hard metal--you will not scrape it off I dont think? I think it would break off 1st?
Ii too set my gaps a little closer, but i dont pull the gauge through the gap. I just gap it a tad looser than the gauge I am using.
I think they wear quickly because of what we ask them to do and the fact that the flame front travel always hits the same side.

 

You re-gap Renesis plugs?

 

I know, I know, the bar is very fragile. You do have to be very careful and you really dont regap after that 1st time--before install.
The denso iridium have much better bars.
I will go to the barless when i can get my dwell changed.
OD

 

Just say no to barred leading plugs.

Unless you want that bar to go through your engine.

BTW - the bar isn't iridium. Only the center electrode.

 

right--- the oems bar is not weilded on very weil. pun intended.
Denso's are much stronger and for the price they damn well better be!.
Have ever heard of this actually happening to anyone? I agree that it is possible with the ngk's
but right now i dont feel like I have the juice to fire the other kind.
OD

 

Yes, several times. Myself included.

 

What barless plugs are you guys using?

 

RX-7 trailing plugs : NGK-BUR9EQP

 

Oh, you lucky FI folks
Any washers needed anyway? Sooner or later i'll join the darkside!

 

You only need washers if you put those plugs in the trailing position also, since they will bottom out and distort the housing if you don't.
In the leading position, they are already the correct length.

 

Oh damn--that would convert me for sure.
OD

 

Thank you Jeff, it's hard to figure such things out without having the plugs at hand

 

Any reason to be changing them every 12k miles? Just curious.

 

Not really, I'm just **** and prefer not to have bad spark which can lead to other issues. Of course, you gotta stay after the coils(if stock) in my opinion also............but not as often.
There are people that haven't changed their plugs in 50k miles............not me!