Copper versus Platinum spark Plugs

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It is true.
Platinum just lasts longer.
I always use copper in my cars.

There may be some instances where platinum is spec'd but I would assume it would just be exotic cars. Most regular vehicles on the road usually come with copper from factory, or at least can use copper as a replacement if they are available.
 
Copper is indeed the best conductor but it does not last long. Platinum is used as a trade-off between conductivity and long-life.

Iridium is better than platinum but does not come close to copper.

Some companies offer platinum-coated copper as another trade-off.

Platinum is factory in tons of cars, with some even using iridium so the maintenance intervals are very long. Toyota is using iridium for sure -- I think the interval is over 100k. I see no reason NOT to use platinum these days. Most street vehicles do not need the copper plugs and the average person doesn't want to change them out every 10k.
 
Originally Posted By: SLCraig
It is true.
Platinum just lasts longer.
I always use copper in my cars.

There may be some instances where platinum is spec'd but I would assume it would just be exotic cars. Most regular vehicles on the road usually come with copper from factory, or at least can use copper as a replacement if they are available.


Sorry man, but you're WAY behind the times.

The overwhelming majority of new cars ship with plats or platinum/iridium hybrids. Very few vehicles come with ol' coppers anymore.

It is absolutely true that copper vs. plat is no performance gain, though. There are no real differences in their actual performance, just longevity.

And BTW, almost all plugs are copper cored. I'm only talking about the tips.
 
Copper is better for performance but you will need to change them very frequently, perhaps every 10k. Here are some of the thermal conductivities of some commonly used metals (Watts / centimeter*Kelvin). As you can see, copper is untouchable. Iridium gives you the best trade-off between performance and lifespan.


Zinc = 1.16
Aluminum = 2.37
Copper = 4.01
Steel = 0.70 - 0.82
Platinum = 0.716
Iridium = 1.47


Platinum-coated copper is actually not a bad trade-off either since you sort of get the best of both worlds.
 
Yes, copper conducts electricity better than platinum, but no on the plugs.

What vehicle and what year?

There are many other reasons, besides conductivity as to why use non-copper sparks. If OEM sparks are platinum or iridium, more often than not, they need to be replaced with the OEM plugs for optimum performance. My Axiom uses a waste spark system, so I will replace my current plugs with the OEM Denso PK16PR11 Double platinum plugs, since WSS is very sensitive to the plug type.

Platinum and iridium plugs also last 2 to 3 times longer than copper plugs, so there is less labor and expense involved into replacing spark plugs.
 
Originally Posted By: SteveSRT8
Sorry man, but you're WAY behind the times.


I suppose.
I've yet to pull the plugs on any car built after 2002, well, ever..
My Saturns came with copper from the factory and the only car I've owned that had platinum from the factory was my Maxima/Altima. I have yet to pull the plugs on the Civic but I assume they are copper. Who knows.

Either way I will replace with copper, as they are stupid easy to replace on the Honda 1.8L. And the plugs are dirt cheap.
 
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Originally Posted By: SteveSRT8
It is true.It is absolutely true that copper vs. plat is no performance gain, though. There are no real differences in their actual performance, just longevity.


I have to disagree with you on this. Refer to my prior post, with waste spark ignition systems, spark plug type does matter.
Some engines maybe more tolerant of different spark plug types than others. 2005+ Tacos come with iridiums in I4 and copper in V6. Properly gapped iridium plug in the correct heat range gives worse gas mileage in a V6 than OEM copper.
 
Doesn't matter, the TIP on a "copper" plug is STEEL. The TIP on an iridium plug is iridium. The CORE of both plugs can still be (and likely is) copper.

If we are debating the TIP material, then why is everybody talking about copper? The tips are either steel, platinum or iridium. With either steel, or iridium/platinum "pucks" on the ground electrode.
 
LOL! The real terminology for the so-called "copper" plugs is, copper-core plugs, not copper plugs all the way to the electrodes.

(**all copper plugs electrodes incl. the grounds, are made of nickel alloy (could be plated also) for erosion resistance**)

Copper is the preferred choice simply because of its thermal properties, not so much on the electrical side of things.

Platinum, Iridium, etc. are the chosen one nowadays mainly for the sake of electrode erosion resistance (which leads to the consistency of firing which deemed especially important to the emission-sensitive OBD-II vehicles).

My takes is to go with at least Platinum or Iridium (depending on vehcile types). I would only use copper core resistor plugs on my OPE such as B&S flatheads, Honda GV pressure washer, etc.

Q.
 
EPA wants you to go 100+k without changing plugs. Or if you have a problem, the manufacturer has to change them under warranty.

Apparantly the new hemi takes regular old copper plugs and a 30k interval.

10k is from back when leaded gas was run. My coppers look good after 30k, just a little rounded, not much gap growth.

Some of the grief over platinums is limited heat ranges in replacement part numbers, so colder plugs than intended were sometimes installed.
 
The electrical resistance of copper vs any other metal does not matter in a spark plug. The voltage is very high and the current is very low. Sometimes spark plugs are made intentionally higher resistance, and usually spark plug wires are made higher resistance on purpose.

The copper core advantage has to do with heat conduction. The copper is not robust at the point of the spark. A higher melting point and more inert metal is much better for that small place.
 
Originally Posted By: eljefino
Apparantly the new hemi takes regular old copper plugs and a 30k interval.


Only the 5.7 ships with coppers. All 6.1 and 6.4 Hemis ship with NGK platinum/iridiums.

And despite what many think, the 5.7 runs great on almost any plug.

Choose your plug by how often you want to fool with it.
 
^ Absolutely correct. Most street cars won't see any difference, it just comes down to how lazy you are with changing them.

I opted for the ultra-sharp Denso Iridium IK20 (0.4mm tip) knowing they need to be changed a lot.
 
It depends on the vehicle. Chrysler "neon" engines, particularly the 2.4L version, require copper plugs. Chrysler has a TSB out to use only the OEM Champion Copper plugs in that motor. I replaced spark plugs on a PT Cruiser with Autolite Double Platinums. The car idled terrible, bucked and sputtered, returned the spark plugs for another set of Autolites, did not resolve the issues. Found the TSB, replaced the plugs with OEM Champion Coppers from the dealer, problem solved.

The Jeep 4.0L is the same way.

My advice is to use OEM plugs. Don't get fancy. It came with those plugs for a reason, and that reason is not all about $.
 
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