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Unread 08-01-2013, 01:05 PM   #1
hemispin
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Hemi spark plugs...why not use platinum?

So I did search and there was a thread about 2 years ago for spark plugs. I've had my new Jeep for a month now. I noticed there's a 30K mile interval to change the spark plugs. From the best I can tell, this engine comes with the conventional "cheapy" ~ $2.00 plugs.

So instead of changing plugs every 30k miles, why not switch them to platinum plugs and get 100k miles out of it? Ignoring the higher cost of platinum plugs, it would be worth it to me for having to do maintenance less often.

Found some interesting info on a Ram truck forum here:

http://www.ramforumz.com/archive/index.php/t-97496.html

Seems there is a "police-spec" iridium plug available. I can't think of a reason why it wouldn't work in the our Jeeps...

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Unread 08-01-2013, 03:15 PM   #2
Webb
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Are you doing yourself ? Or taking the new plugs to the dealer ? I thought about it but the scammers might put the cheap ones and keep the good one.
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Unread 08-01-2013, 04:27 PM   #3
tjkj2002
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Quote:
Originally Posted by hemispin View Post
So I did search and there was a thread about 2 years ago for spark plugs. I've had my new Jeep for a month now. I noticed there's a 30K mile interval to change the spark plugs. From the best I can tell, this engine comes with the conventional "cheapy" ~ $2.00 plugs.

So instead of changing plugs every 30k miles, why not switch them to platinum plugs and get 100k miles out of it? Ignoring the higher cost of platinum plugs, it would be worth it to me for having to do maintenance less often.

Found some interesting info on a Ram truck forum here:

http://www.ramforumz.com/archive/index.php/t-97496.html

Seems there is a "police-spec" iridium plug available. I can't think of a reason why it wouldn't work in the our Jeeps...
If it came with copper core plugs from the factory that is what the ignition system is designed around and changing the resistance can and will cause issues.Plus copper core plugs give the best spark anyways and easy to change on the 5.7.I'm pretty sure yours take nickle plugs now anyways.

One big issue with extended change intervals is when you actually do change them plug wires,and in your case coil boots will seize on the plugs adding to the expense.See it everyday at work with GM vehicles that use iridium plugs,99% of the time the plug wires will not come off without destroying the wires.
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Unread 08-01-2013, 05:08 PM   #4
Dave2002ti
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Maybe

Quote:
Originally Posted by tjkj2002 View Post
If it came with copper core plugs from the factory that is what the ignition system is designed around and changing the resistance can and will cause issues.Plus copper core plugs give the best spark anyways and easy to change on the 5.7.I'm pretty sure yours take nickle plugs now anyways.

One big issue with extended change intervals is when you actually do change them plug wires,and in your case coil boots will seize on the plugs adding to the expense.See it everyday at work with GM vehicles that use iridium plugs,99% of the time the plug wires will not come off without destroying the wires.
Maybe its the techs who dont have a clue about how to get plug wires etc off w/o damaging them beyond repair. BMw and Benz owners with 100K mile spark plug changes would scream bloody murder if they were billed additional $500+ for damaged plug wires.
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Unread 08-01-2013, 06:27 PM   #5
loveracing1988
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Originally Posted by Dave2002ti View Post

Maybe its the techs who dont have a clue about how to get plug wires etc off w/o damaging them beyond repair. BMw and Benz owners with 100K mile spark plug changes would scream bloody murder if they were billed additional $500+ for damaged plug wires.
Try doing a set of plugs in a mini van with 100k and tell me how easy it is.
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Unread 08-01-2013, 07:19 PM   #6
tjkj2002
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Originally Posted by Dave2002ti View Post
Maybe its the techs who dont have a clue about how to get plug wires etc off w/o damaging them beyond repair. BMw and Benz owners with 100K mile spark plug changes would scream bloody murder if they were billed additional $500+ for damaged plug wires.
When the plug wires litterly melt to the plug there is nothing you can do.Common issue on the GENII Chrysler 4.7 with 16 spark plugs(top set of plugs),the coil boots melt to the plugs.It's so common there is a special tool made to remove the ripped boot off the spark plug so you can remove the plug.

Quote:
Originally Posted by loveracing1988 View Post
Try doing a set of plugs in a mini van with 100k and tell me how easy it is.
X2....................

GM V6's are the worst,more so those back 3 wires.
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Unread 08-01-2013, 08:11 PM   #7
elarm1
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Go ahead and put 16 platinums in your hemi and see what happens! Just put the coppers in there and be done with it for 30k. Hemis don't like platinums
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Unread 08-02-2013, 12:15 PM   #8
hemispin
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Just to clarify, I have a mechanic work on my cars now. I'm at a point where I am fully capable of doing the work, but it's not worth my time any more. An oil change is super simple, but it's a hassle to buy the oil, swap it from the drain pan to a jug, and then recycle it. I'd rather pay a bit more and not have to hassle with it. I know I'm not alone here

I'm considering changing to platinum or iridium plugs at the 30k interval. I haven't made up my mind. A little dielectric grease inside the boots and a dab of anti-seize to the spark plug threads should mitigate future issue.


Quote:
Originally Posted by tjkj2002 View Post
If it came with copper core plugs from the factory that is what the ignition system is designed around and changing the resistance can and will cause issues.Plus copper core plugs give the best spark anyways and easy to change on the 5.7.I'm pretty sure yours take nickle plugs now anyways.

One big issue with extended change intervals is when you actually do change them plug wires,and in your case coil boots will seize on the plugs adding to the expense.See it everyday at work with GM vehicles that use iridium plugs,99% of the time the plug wires will not come off without destroying the wires.
Interesting point. Not trying to be argumentative, but I'm not so sure there would be a significant change in resistance. There is infinite resistance across the spark plug gap. Do you know what the difference in resistance is? Does it take less voltage to "spark" on the copper vs. iridium plugs?


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GM vehicles are the worst.
Fixed!!
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Unread 08-02-2013, 01:53 PM   #9
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Yikes, I'm at 76K with the original plugs and wires with no problems. I have the transmission shudder, and the dealer was trying to get me to pay to change them, etc at about 40K - saying it could be causing the problems. I politely told her that if Chrysler thought the plugs were causing my problems, then to change them on their own dime since I have been having this problem since 12K miles.

.... They said my plugs were fine. Went through it all again about 3K miels ago.. same outcome.
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Unread 08-02-2013, 06:15 PM   #10
tjkj2002
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Originally Posted by hemispin View Post


Interesting point. Not trying to be argumentative, but I'm not so sure there would be a significant change in resistance. There is infinite resistance across the spark plug gap. Do you know what the difference in resistance is? Does it take less voltage to "spark" on the copper vs. iridium plugs?




Fixed!!
There is a big difference in resistance and at least once a week I get a HEMI,4.7,or 3.7 that comes in with complaints of poor fuel mileage and/or misfires and they just replaced the plugs.Pull one plug see it's platinum or iridium and suggest the correct plugs(copper cores) and all there issues disappear.The worst offenders are those E3 plugs,they don't run well in any engine I've seen them installed in.
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Unread 08-02-2013, 07:53 PM   #11
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Quote:
Originally Posted by hur1ey02
Yikes, I'm at 76K with the original plugs and wires with no problems. I have the transmission shudder, and the dealer was trying to get me to pay to change them, etc at about 40K - saying it could be causing the problems. I politely told her that if Chrysler thought the plugs were causing my problems, then to change them on their own dime since I have been having this problem since 12K miles.

.... They said my plugs were fine. Went through it all again about 3K miels ago.. same outcome.
Wow 76k my jeep started running sluggish at 36k miles and I had no clue about the 30k spark plug interval this is my first hemi I changed them out and put fresh oil in and she came back alive
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Unread 08-02-2013, 08:08 PM   #12
hemispin
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Quote:
Originally Posted by tjkj2002 View Post
There is a big difference in resistance and at least once a week I get a HEMI,4.7,or 3.7 that comes in with complaints of poor fuel mileage and/or misfires and they just replaced the plugs.Pull one plug see it's platinum or iridium and suggest the correct plugs(copper cores) and all there issues disappear.The worst offenders are those E3 plugs,they don't run well in any engine I've seen them installed in.
That's the answer I was looking for. Thank you for the REAL WORLD experience.
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Unread 08-03-2013, 07:55 PM   #13
kentman
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Originally Posted by tjkj2002 View Post
There is a big difference in resistance and at least once a week I get a HEMI,4.7,or 3.7 that comes in with complaints of poor fuel mileage and/or misfires and they just replaced the plugs.Pull one plug see it's platinum or iridium and suggest the correct plugs(copper cores) and all there issues disappear.The worst offenders are those E3 plugs,they don't run well in any engine I've seen them installed in.
I ran 16 platinum plugs in the Hemi in my XK for 30K miles, and I had zero issues. mpg was the same as I am getting now with copper plugs. I had zero misfires.

When I took the platinum plugs out, they looked fine. They could have gone longer. I pitched them and went with a new batch of copper from 90K to 120K miles. I have another 11K miles until the next swap. I willl see how the copper plugs look after 30K miles.

I already have another batch of 16 copper plugs ready to go for the next swap in '14. I stocked up when there was a great sale a while back. I bought 32 copper plugs for the XK and 16 platinum plugs for the WJ. The 4.7L HO motor in the WJ requires platinum plugs.

The dealer in Orlando put in copper when I specifically requested platinum on the WJ. After 30K miles on the copper plugs, the central electrode was gone. I was pretty ticked. I will not be using that dealer again. You would think that a big dealer like that would know how to put in the proper plugs.
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Unread 08-04-2013, 06:37 PM   #14
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Originally Posted by kentman View Post
I ran 16 platinum plugs in the Hemi in my XK for 30K miles, and I had zero issues. mpg was the same as I am getting now with copper plugs. I had zero misfires.

When I took the platinum plugs out, they looked fine. They could have gone longer. I pitched them and went with a new batch of copper from 90K to 120K miles. I have another 11K miles until the next swap. I willl see how the copper plugs look after 30K miles.

I already have another batch of 16 copper plugs ready to go for the next swap in '14. I stocked up when there was a great sale a while back. I bought 32 copper plugs for the XK and 16 platinum plugs for the WJ. The 4.7L HO motor in the WJ requires platinum plugs.

The dealer in Orlando put in copper when I specifically requested platinum on the WJ. After 30K miles on the copper plugs, the central electrode was gone. I was pretty ticked. I will not be using that dealer again. You would think that a big dealer like that would know how to put in the proper plugs.
That's what they all say and at 30k copper core plugs will be worn to the point of replacement.
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Unread 08-09-2013, 01:26 AM   #15
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That's what they all say and at 30k copper core plugs will be worn to the point of replacement.
I would say beyond the point of replacement. The gap was huge at 30K miles on the 4.7L HO. I had not planned on using copper. I should have never let the dealer do the plugs at 60K miles. If I ever do that again, then I will pull one to check the plug model number after they are done.
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