How does the difference in material conductivity affect the performance of the plug or engine?
Would you use Iridium Plugs in a Ford 4.6 DOHC?
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Originally Posted By: tom slick
How does the difference in material conductivity affect the performance of the plug or engine?
Its a very small trade off. You won't see any real world performance gains on a stock car.
Maybe on a heavily modified car you will see a little more power with the copper plugs, but they don't last as long.
The motorcraft platniums, or double platnium plugs are perfect, and suggested by Ford for this motor.
And you won't have to replace them every year, like you would with a copper plug.
How does the difference in material conductivity affect the performance of the plug or engine?
Its a very small trade off. You won't see any real world performance gains on a stock car.
Maybe on a heavily modified car you will see a little more power with the copper plugs, but they don't last as long.
The motorcraft platniums, or double platnium plugs are perfect, and suggested by Ford for this motor.
And you won't have to replace them every year, like you would with a copper plug.
Does a 12 year old Lincoln fit into the "makes a difference" category? wouldn't the other varibles in the ign. system cause a larger effect than the minute conductivity difference? i.e. tiny gap differences, tiny compression differences, length of ign cables, etc?
OVERKILL
$100 Site Donor 2021
It makes no difference on performance unless your ignition is not up the task of jumping the gap on a plug under "heavy load" conditions.
Copper plugs are easier on an ignition system.
Copper plugs are easier on an ignition system.
+1 on using standard plugs. I've had bad luck with the 'fancy stuff'
Also, this post is the 100,000 post in Mech./Maintenance.
Also, this post is the 100,000 post in Mech./Maintenance.
If you don't want to fork out lots of $$ on motorcraft plugs the best aftermarket plugs for fords are the NGK g-power best plugs for the money and they work well with ford, I have some in my old Ford aerostar with the 4.0l V6 and it runs great, I had motorcraft in their before and I find the engine runs just as good without the oem plugs.
Originally Posted By: OVERK1LL
Copper plugs are easier on an ignition system.
how? Maybe I am missing something? Have you got an article for me to read? Honestly, I want to learn how the small difference in resistivity makes any real difference in anything other that a super high performance application.
Looking at numbers:
The ignition wires connected to the plug have 3000 ohm/ft (250 ohm/inch) or if they are high performance 50 ohm/ft (4.16 ohm/inch). A V-8 might have a 24 inch difference in length from shortest to longest, 100 ohms.
The difference in plug material resistivity is measured in micro ohms which are .000001 ohms. Copper's resistance is .00000424 ohm/inch, Iridium's resistance is .00001346 ohm/inch, the difference is .00000922 ohm/inch. One inch of high performance ignition wire makes 451,000 times more difference than the plug material in resistance.
Copper plugs are easier on an ignition system.
how? Maybe I am missing something? Have you got an article for me to read? Honestly, I want to learn how the small difference in resistivity makes any real difference in anything other that a super high performance application.
Looking at numbers:
The ignition wires connected to the plug have 3000 ohm/ft (250 ohm/inch) or if they are high performance 50 ohm/ft (4.16 ohm/inch). A V-8 might have a 24 inch difference in length from shortest to longest, 100 ohms.
The difference in plug material resistivity is measured in micro ohms which are .000001 ohms. Copper's resistance is .00000424 ohm/inch, Iridium's resistance is .00001346 ohm/inch, the difference is .00000922 ohm/inch. One inch of high performance ignition wire makes 451,000 times more difference than the plug material in resistance.
OVERKILL
$100 Site Donor 2021
Originally Posted By: tom slick
Originally Posted By: OVERK1LL
Copper plugs are easier on an ignition system.
how? Maybe I am missing something? Have you got an article for me to read? Honestly, I want to learn how the small difference in resistivity makes any real difference in anything other that a super high performance application.
Looking at numbers:
The ignition wires connected to the plug have 3000 ohm/ft (250 ohm/inch) or if they are high performance 50 ohm/ft (4.16 ohm/inch). A V-8 might have a 24 inch difference in length from shortest to longest, 100 ohms.
The difference in plug material resistivity is measured in micro ohms which are .000001 ohms. Copper's resistance is .00000424 ohm/inch, Iridium's resistance is .00001346 ohm/inch, the difference is .00000922 ohm/inch. One inch of high performance ignition wire makes 451,000 times more difference than the plug material in resistance.
The biggest source of resistance is the gap.......
The "flat" face of the copper plugs, especially when fresh, give you a nice sharp edge for the spark to jump from. The Iridium and Platinum plugs do not have the same sharp edges on them.
As copper plugs wear, that "edge" wears off, making the plugs more difficult to fire, since it now has to fire from a rounded surface.
Originally Posted By: OVERK1LL
Copper plugs are easier on an ignition system.
how? Maybe I am missing something? Have you got an article for me to read? Honestly, I want to learn how the small difference in resistivity makes any real difference in anything other that a super high performance application.
Looking at numbers:
The ignition wires connected to the plug have 3000 ohm/ft (250 ohm/inch) or if they are high performance 50 ohm/ft (4.16 ohm/inch). A V-8 might have a 24 inch difference in length from shortest to longest, 100 ohms.
The difference in plug material resistivity is measured in micro ohms which are .000001 ohms. Copper's resistance is .00000424 ohm/inch, Iridium's resistance is .00001346 ohm/inch, the difference is .00000922 ohm/inch. One inch of high performance ignition wire makes 451,000 times more difference than the plug material in resistance.
The biggest source of resistance is the gap.......
The "flat" face of the copper plugs, especially when fresh, give you a nice sharp edge for the spark to jump from. The Iridium and Platinum plugs do not have the same sharp edges on them.
As copper plugs wear, that "edge" wears off, making the plugs more difficult to fire, since it now has to fire from a rounded surface.
Originally Posted By: OVERK1LL
Originally Posted By: tom slick
Originally Posted By: OVERK1LL
Copper plugs are easier on an ignition system.
how? Maybe I am missing something? Have you got an article for me to read? Honestly, I want to learn how the small difference in resistivity makes any real difference in anything other that a super high performance application.
Looking at numbers:
The ignition wires connected to the plug have 3000 ohm/ft (250 ohm/inch) or if they are high performance 50 ohm/ft (4.16 ohm/inch). A V-8 might have a 24 inch difference in length from shortest to longest, 100 ohms.
The difference in plug material resistivity is measured in micro ohms which are .000001 ohms. Copper's resistance is .00000424 ohm/inch, Iridium's resistance is .00001346 ohm/inch, the difference is .00000922 ohm/inch. One inch of high performance ignition wire makes 451,000 times more difference than the plug material in resistance.
The biggest source of resistance is the gap.......
The "flat" face of the copper plugs, especially when fresh, give you a nice sharp edge for the spark to jump from. The Iridium and Platinum plugs do not have the same sharp edges on them.
As copper plugs wear, that "edge" wears off, making the plugs more difficult to fire, since it now has to fire from a rounded surface.
OVERK1LL,
Are you saying that the "flat face" of the copper plugs offsets the point that Tom made regarding the negligible difference in resistance?
This turned out to be a very interesting thread so let's bring it back to life.
Anyone put Iridium's into their 4.6 since the last post? What's the overall consensus versus Platinum? Any upside to them?
Originally Posted By: tom slick
Originally Posted By: OVERK1LL
Copper plugs are easier on an ignition system.
how? Maybe I am missing something? Have you got an article for me to read? Honestly, I want to learn how the small difference in resistivity makes any real difference in anything other that a super high performance application.
Looking at numbers:
The ignition wires connected to the plug have 3000 ohm/ft (250 ohm/inch) or if they are high performance 50 ohm/ft (4.16 ohm/inch). A V-8 might have a 24 inch difference in length from shortest to longest, 100 ohms.
The difference in plug material resistivity is measured in micro ohms which are .000001 ohms. Copper's resistance is .00000424 ohm/inch, Iridium's resistance is .00001346 ohm/inch, the difference is .00000922 ohm/inch. One inch of high performance ignition wire makes 451,000 times more difference than the plug material in resistance.
The biggest source of resistance is the gap.......
The "flat" face of the copper plugs, especially when fresh, give you a nice sharp edge for the spark to jump from. The Iridium and Platinum plugs do not have the same sharp edges on them.
As copper plugs wear, that "edge" wears off, making the plugs more difficult to fire, since it now has to fire from a rounded surface.
OVERK1LL,
Are you saying that the "flat face" of the copper plugs offsets the point that Tom made regarding the negligible difference in resistance?
This turned out to be a very interesting thread so let's bring it back to life.
Anyone put Iridium's into their 4.6 since the last post? What's the overall consensus versus Platinum? Any upside to them?
Originally Posted By: OVERK1LL
The biggest source of resistance is the gap.......
The "flat" face of the copper plugs, especially when fresh, give you a nice sharp edge for the spark to jump from. The Iridium and Platinum plugs do not have the same sharp edges on them.
As copper plugs wear, that "edge" wears off, making the plugs more difficult to fire, since it now has to fire from a rounded surface.
+1, and the surface of all "copper" plugs are actually steel, not copper, and platinum and iridium plugs have the same copper cores internally, so there goes the resistance argument.
Anyhow, it is really the plug's sharpness and the gap that make the most difference. As the plug wear and the gap widen, your resistance goes all over.
The most important thing to the firing is actually how high of the voltage difference goes between the gap before the di-electric break down happen (aka firing). Too high it would cause a misfire once in a while, and too close of a gap will reduce the flame speed. If your car is that picky about firing voltage, your coil (which step up the voltage from the 12V) needs to be replaced.
The biggest source of resistance is the gap.......
The "flat" face of the copper plugs, especially when fresh, give you a nice sharp edge for the spark to jump from. The Iridium and Platinum plugs do not have the same sharp edges on them.
As copper plugs wear, that "edge" wears off, making the plugs more difficult to fire, since it now has to fire from a rounded surface.
+1, and the surface of all "copper" plugs are actually steel, not copper, and platinum and iridium plugs have the same copper cores internally, so there goes the resistance argument.
Anyhow, it is really the plug's sharpness and the gap that make the most difference. As the plug wear and the gap widen, your resistance goes all over.
The most important thing to the firing is actually how high of the voltage difference goes between the gap before the di-electric break down happen (aka firing). Too high it would cause a misfire once in a while, and too close of a gap will reduce the flame speed. If your car is that picky about firing voltage, your coil
Originally Posted By: ET16
Originally Posted By: SHOZ
Autolite XP Iridiums work great in Fords. Or Mazdas or Hyundais....
Get a rebate too from Honeywell.
That would be my suggestion, too.
I read that the Autolite plugs don't use enough Iridium to qualify as a full Iridium Plug. I have to go dig for that link.
Originally Posted By: SHOZ
Autolite XP Iridiums work great in Fords. Or Mazdas or Hyundais....
Get a rebate too from Honeywell.
That would be my suggestion, too.
I read that the Autolite plugs don't use enough Iridium to qualify as a full Iridium Plug. I have to go dig for that link.
Copper core plugs can be plain steel, or precious metal tipped.
It is for heat transfer inside the plug.
Who cares what means the mfr. uses for this?
It is a non issue. Just one means to an end.
Precious metal tips last much longer than plain steel, and are smaller for better flow in/out of gasses.
Platinum actually has greater resistance than plain steel, and iridium has less than steel.
It is for heat transfer inside the plug.
Who cares what means the mfr. uses for this?
It is a non issue. Just one means to an end.
Precious metal tips last much longer than plain steel, and are smaller for better flow in/out of gasses.
Platinum actually has greater resistance than plain steel, and iridium has less than steel.
Originally Posted By: tom slick
how? Maybe I am missing something? Have you got an article for me to read? Honestly, I want to learn how the small difference in resistivity makes any real difference in anything other that a super high performance application.
Looking at numbers:
The ignition wires connected to the plug have 3000 ohm/ft (250 ohm/inch) or if they are high performance 50 ohm/ft (4.16 ohm/inch). A V-8 might have a 24 inch difference in length from shortest to longest, 100 ohms.
The difference in plug material resistivity is measured in micro ohms which are .000001 ohms. Copper's resistance is .00000424 ohm/inch, Iridium's resistance is .00001346 ohm/inch, the difference is .00000922 ohm/inch. One inch of high performance ignition wire makes 451,000 times more difference than the plug material in resistance.
I think you may be forgetting that many cars have NO plug wires at all!
I have 16 plugs and no plug wires.
how? Maybe I am missing something? Have you got an article for me to read? Honestly, I want to learn how the small difference in resistivity makes any real difference in anything other that a super high performance application.
Looking at numbers:
The ignition wires connected to the plug have 3000 ohm/ft (250 ohm/inch) or if they are high performance 50 ohm/ft (4.16 ohm/inch). A V-8 might have a 24 inch difference in length from shortest to longest, 100 ohms.
The difference in plug material resistivity is measured in micro ohms which are .000001 ohms. Copper's resistance is .00000424 ohm/inch, Iridium's resistance is .00001346 ohm/inch, the difference is .00000922 ohm/inch. One inch of high performance ignition wire makes 451,000 times more difference than the plug material in resistance.
I think you may be forgetting that many cars have NO plug wires at all!
I have 16 plugs and no plug wires.
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