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Discussion Starter #1 (Edited)
This appears to be the first time that the plugs have been changed on this vehicle based on plug gap and wear. (~.062)

92k miles


I broke the stud that holds the coil on cylinder #1.

Do NOT over-tighten these.

I am a 200lb 28 y/o, and simply turned em one time too many with a 1/2" ratchet with one hand.
 

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Its only plastic, gotta go easy... what plugs you install?
 

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Discussion Starter #3
Broken

Old vs new


92k miles its way out of spec obviously (should be .043)


Drive home from work yesterday was 16.5mpg
Got this omw to work.


They are NGK iridiums
 

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I put them in 40k ago. Still running great... would love to pull them to check for wear though, hopefully soon.
 

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Discussion Starter #5 (Edited)
I put them in 40k ago. Still running great... would love to pull them to check for wear though, hopefully soon.
Sweet! Thanks. I'm getting some negative feedback on iridiums on jeep forum from the WK guys.

"Waste of money! "
Sheesh, maybe i spent an extra $5-10?

What about all the guys that pay for a shop install... there is a serious waste of money...

"Your Coils are designed for COPPERS, This will undoubtedly cause your engine to explode in spectacular fashion!"

:icon_confused:
 

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Discussion Starter #6
In case anyone actually checks this thread, I was advised to run a larger than stock gap on my iridiums to increase resistance and be closer in that regard to the stock coppers. I'm going to go ahead and do that.
 

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In case anyone actually checks this thread, I was advised to run a larger than stock gap on my iridiums to increase resistance and be closer in that regard to the stock coppers. I'm going to go ahead and do that.
???? I've never heard of that? NOT saying its wrong, just saying with all the myths floating around about ignition and spark plugs, I suspect that it is just another one of those myths, but I don't know. And the fact a lot of newer motors have problems with different brands/types of plugs, which no one has explained the reason why to my satisfaction, it just adds to the confustion.

Increasing the gap will increase resistance, that is true.

What I don't know is true:

Is if Platinum and Iridium plugs have any different resistance than Copper plugs. The more exotic metals are used because they last longer under the stress of carrying an electric arc over the surface NOT because they have a lower resistance.

I don't know if minor differences in resistance has any real effect on the ignition system as well. If it did, you would think that the spark plug wires being different length would throw off ignition systems, yet most motor have spark plug wires of different lengths and the wires have far more resistance per foot than the plugs themselves.

I don't think the plug gap is determined by the manufacturer by resistance, I'm guessing it is more likely experimentally derived while testing the engine design according to all sorts of other variables, the least of which would be resistance, but I do NOT know that for a fact.

Finally, the plug gap recommendation from the manufacturer has some practicallitity to it. The gap will increase as the plug wears out, so the recommendation usually means the smallest gap that works well, so that as the plug wears the performance doesn't suffer. So, your increased gap may still be well in the range of good performance for the motor, but since its closer to the "too big" of a gap, it means you'll suffer poor performance sooner as the gap grows. BUT, that is just speculation on my part.
 

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While I don't mind paying $10 for a 100K plug, I have read several threads where members have had bad experience with non OEM plugs.

Due to the negative feedback, I have stuck with OEM and replaced them every 30K.

You are not suppose to adjust the gap of platinum or iridium plugs due to their fragile electrode tips.
 

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If plugs come pre-gapped, they usually have a plastic tube around the threads covering the electrode end, to prevent the electrode from bending and changing the set gap during handling and shipping.

NGK's often come with the plastic tube around the threads, protecting the electrodes.
 

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Discussion Starter #11
I definitely appreciate the responses guys. :banger:

I have not attempted to pull the plugs and gap them yet, and based on what your saying I will just leave them alone unless another code pops up.
 

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Discussion Starter #12
While I don't mind paying $10 for a 100K plug, I have read several threads where members have had bad experience with non OEM plugs.

Due to the negative feedback, I have stuck with OEM and replaced them every 30K.

You are not suppose to adjust the gap of platinum or iridium plugs due to their fragile electrode tips.
I only paid like $6 a plug, so I'll check them in ~30k and see how they look. I don't quite expect 100k.
 

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Discussion Starter #16
No problems with them.

Quicker starts. Mpg slightly better.

Along with my hypertech tune it runs overall much better.
 

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What did you do with hypertech? Did it Improve, or change shifting?
 

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Discussion Starter #18 (Edited)
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