Not really impressed with Iridium plugs

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trapster

trapster

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Not really impressed with Iridium plugs. I pulled these out of my 08 300c 5.7L Hemi after 60k Miles of use. Most of the plugs were worn to a nub, but one was missing the anode all together. The car seemed to run fine, but the dealership did say there were some misses indicated. I put copper plugs in and it is running better, but we are having a cold snap here now which also makes a difference.
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60k miles is pretty decent...? I though Iridiums lasted longer than coppers. It's what the new Hemis are designed to run on anyway.
 
They must be Champion spark plugs. Champs have a rep of falling apart. They run good when new but just don't hold up. If replacing, try NGK or Autolites.
 
I still think the enginerds forgot how to count. 1 hole 1 spark plug. Thats all they needs. Two plugs dont make a pinch o coonshit difference. Fuel mileage sure dont show it.

The snomobile “fast guys” run iridiums if i recall or was it palladium?
Idea was it would burn off during a lean event, therby saving a piston(cookie) and or a jug.

Fast guys tune right to the edge of kaboom,nothing worse than putting a new cookie in on a saturday so you can keep riding.

I will never forget his words”she’s a weapon now!!”
Yup,a grenade we said, followed with the pin is pulled....and who’s got a tow strap??

Oops,sorry, you may have a lean condition, a very small lean condition.
 
you got 8 cylinders...try one of each brand in them.
 
Were they gapped by someone? Because you're not supposed to gap them, you buy what you need (gap and heat range) and check them. You can gap them but you need to be very, very careful or they break, easily. I've ran Iridium in turbo cars (where gap is critical) and you can tell when they are going bad with hard misses (spark blow out) under boost. I've ran NGK, Autolite and Denso with good results. They last 25k-30k under turbo engine conditions.
 
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Can't speak for anything else other than my KX 250 but for woods riding they are a game changer. I couldn't imagine having to pay for those things in an automobile.... Ouch....

JW
 
I like ngk in my hemis, but the price has crept up recently. Especially with 16 plugs... I have tried Bosch my last 2 changes (one vvt, one non eagle) and they have been doing great. Even eliminated a faint idle miss on the vvt hemi.
 
They were Champions, I did check the gap when installed, but I didn't see any evidence of the iridium part breaking, just worn down.
 
dano said:
Were they gapped by someone? Because you're not supposed to gap them, you buy what you need (gap and heat range) and check them. You can gap them but you need to be very, very careful or they break, easily. I've ran Iridium in turbo cars (where gap is critical) and you can tell when they are going bad with hard misses (spark blow out) under boost. I've ran NGK, Autolite and Denso with good results. They last 25k-30k under turbo engine conditions.
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So far, I have never seen pre-gapped iridium plugs. The only pre-gapped plugs I am aware of are the Bosch Fine Wire platinum. It clearly says in footnotes not to gap, as it will break the tips off. The iridium plugs have no such footnote and show different gaps for different applications.
 
I too have had to re cap iridium plugs you just do it very carefully, but supposed to cause a hotter spark, have ran them in my turbo neon never had a problem, and after break in of current turbo build will put them in it as well
 
Maybe 60k miles was a bit much to ask. but if I remember they were supposed to last 75k.
 
RustyRatRod said:
So far, I have never seen pre-gapped iridium plugs. The only pre-gapped plugs I am aware of are the Bosch Fine Wire platinum. It clearly says in footnotes not to gap, as it will break the tips off. The iridium plugs have no such footnote and show different gaps for different applications.
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Interesting, Its been several years since I bought them, I look now and even the part numbers I used to buy pre-gapped no longer give a gap. I see Denso now has a procedure for gaping them and also state no warranty if broken.
 
trapster said:
They were Champions, I did check the gap when installed, but I didn't see any evidence of the iridium part breaking, just worn down.
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The iridium core in the "positive" anode is not meant to be wear resistant, it is designed to be misfire resistant to wear and possible fouling due to less than optimum eng.
conditions. The material is supposed to promote a superior conductivity that encourages the spark to prefer it and the "jump" to taking the fouled/contaminated ceramic to
ground, especially important under high cyl. pressures and lean conditions which make it harder for the spark to jump.
I have been seeing a number of plug failures in the last few years, even OE ones from reputable mfrs., including the anode separating and dropping down resting nicely on
the ground. Some have dropped the ceramic cone, and it sits there like a little shroud, lol! Most of these are newer, smaller designs to accommodate the tight fit in some
of these new chamber/valve configurations, esp Direct Injection units............................
Is there anything left visible in the core of the ceramic of the "missing" anode if You bend/cut the ground out of the way? That does look like evidence of an unwelcome
guest in that shot of the piston, it could have failed and still burned at the fracture until it plasma'd itself off & fell in.................
 
It looks like it broke off, and may have done so 10's of thousands of miles ago. there was no evidence of it still being in the cylinder and I didn't think the damage was bad enough to warrant any kind of repair. I guess having 2 plugs per cylinder masked the ill effect of loosing a plug. :) although I am pretty sure that is not the reason behind having the extra plug.
 
I guess, over time the Iridiums spark gap increases, dramatically, so what is the point of gapping it to start
 
I've changed two sets of iridiums in GM cars

1 set was in my Mother's 09 Malibu 2.4L @ 94k miles and they looked brand new and had nearly zero wear. Gap may have opened by .001 or .002. Dont know who made the OEs as they were branded as AC Delco

1 set was in my 2012 Cruze 1.4L Turbo @ 68k due to a bad coil, there was also no noticeable wear but one plug was green on the top and replaced all 4 for insurance. These were NGK and went with the same OE ones.

I would swap in some Denso or NGK iridiums and be on your way.
 
trapster said:
It looks like it broke off, and may have done so 10's of thousands of miles ago. there was no evidence of it still being in the cylinder and I didn't think the damage was bad enough to warrant any kind of repair. I guess having 2 plugs per cylinder masked the ill effect of loosing a plug. :) although I am pretty sure that is not the reason behind having the extra plug.
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Just help with ole emissions would be my guess why 2 plugs.
 
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