Spark Plugs: Platinum vs. Copper

[Eroc]

I will be replacing my spark plugs on my 2001 Explorer Sport (4.0 L - SOHC). The guy at Auto Zone say's to use the more expensive platinum plug's since that’s what came from the factory. Makes sense... BUT, can I use the less expensive copper plugs? Will performance be lost? Any advice would be much appreciated!!

I am changing them because my check engine light is on, and it gave me P0301 and P0305 code's.

 

[Dono]

I have been told copper is better for performance.
The down side is that they don't last as long.

 

[DUNE RCR]

I've always stuck with the motorcraft finewire platinum spark plugs. I know with copper tipped plugs you will be changing them more often since the center electrode will tend to erode faster.

 

[RomeovilleIL]

Realistically you won't notice a difference between the plugs in a stock application. Both will run fine. Big difference is copper lasts 10-15k miles, platinum up to 100k. Stick with standard plugs - the splitfire and most bosch plugs seem to give the engines trouble with random misfire or pinging.

 

[swshawaii]

Realistically you won't notice a difference between the plugs in a stock application. Both will run fine. Big difference is copper lasts 10-15k miles, platinum up to 100k. Stick with standard plugs - the splitfire and most bosch plugs seem to give the engines trouble with random misfire or pinging.

Ditto. You'll be glad you used the 100K platinums after they're installed.
Use a thin coat of anti seize, that's a long interval for aluminum heads.
Did it throw the 301/305 codes at the same time? If so, may not be plugs.

 

[koda2000]

unless you just can't come up with the money for at least single platinums, don't bother with the copper plugs. they will not last very long in a multi-spark high energy ignition system. buy motorcraft or autolite plugs (same thing) and i doubt you'd even get 10k out of the copper plugs.

 

[FIND]

Copper plugs don't last very long in waste fire multi-spark ignition systems. Don't waste money on them. Personally, I only buy iridium plugs, because they are only a little more money than the double platinums that came with the truck from the factory. I think it was less than a buck more to get the autolite XPs versus the double platinums that came with it from the factory.

 

[Eroc]

Great advice! Platinum it is.

 

[SoNic67]

Even Ford switched to Platinum fine-tip plugs on newer vehicles. Iridium fine-tip is the way to go.
Copper is ancient history and stories, has no advantage on our electronic coil system. Platinum is just unfit for the wasted spark system used on Explorer, Dual Platinum is the minimum possible.
After all that work, is it worth saving $20-30 for the 10 year lifetime and not get Iridium???

PS: For the people that still think that copper is better conductor than iridium - remember that the wires have resistors embedded to lower the electro-magnetic interference. Resistors that are 1000 times bigger than any plug.

 

[2000StreetRod]

firing voltage?

I wonder for an equivalent gap and chamber pressure if the fine tip iridium spark plugs fire at a lower voltage due to the smaller cross section area than the larger copper core plugs. If so, the gap should be larger for the iridium plugs than the copper plugs to achieve the same firing voltage. So far I'm having good luck with my Champion Truck Plugs but I only drive my Sport about 3,000 miles a year.

 

[FIND]

I wonder for an equivalent gap and chamber pressure if the fine tip iridium spark plugs fire at a lower voltage due to the smaller cross section area than the larger copper core plugs. If so, the gap should be larger for the iridium plugs than the copper plugs to achieve the same firing voltage. So far I'm having good luck with my Champion Truck Plugs but I only drive my Sport about 3,000 miles a year.
View attachment 71386

The cross sectional area is not small enough to make much difference, especially on resistor wires.

 

[Dono]

Sorry guys...I didn't exactly qualify my earlier post. I should have.
For my application, its copper all the way. I need the heat disipation of the cooler plug to help fight my detonation.
I agree completely the OP should be buying the iridium, or double platinum for his application. I also agree to stay away from split fire type plugs. I tried them in my stock motor and it tore them apart in no time at all.

 

[deweyville65]

For $3.00 each, I use Autolite #605- I believe thats the p/n -platinum plugs from AutoZone. 96 4.0 OHV. They work for me.

 

[Eroc]

Yeah you can't beat Platinum for $3. I'm headed out to buy some now. What's the deal with double platinum?? I don't see double copper, haha.

 

[SoNic67]

I don't see double copper, haha.

Because copper is for cars build in 1950, with distributor cap. They didn't have dual polarity sparks. Any car build after 1985 have 'waste spark' system with shared coils for two cylinders. Half of cylinders have inverse polarity spark.

haha? Sure, whatever...

PS: Temperature/heat range of the plugs has nothing to do with the tip material. Inside conductor is copper in all spark plugs, only a small tip is iridium/platinum. They don't put solid platinum inside ceramic!
Heat is mostly related to the length of ceramic nose, you can get a platinum with lower heat range by reading the heat numbers.
Timing advance or lean mixture can make you car run hot, not the plugs.
http://www.ngksparkplugs.com/tech_support/spark_plugs/p2.asp
http://en.wikipedia.org/wiki/Spark_plug#Heat_range

I wonder for an equivalent gap and chamber pressure if the fine tip iridium spark plugs fire at a lower voltage due to the smaller cross section area than the larger copper core plugs. If so, the gap should be larger for the iridium plugs than the copper plugs to achieve the same firing voltage.

Actually, the gap is the same because, once ignited, arc voltage is dependent only of arc length (gap). But the ignition voltage, usually 10 times higher, is lowered in a fine tip electrode to only some 4 times higher, leading to less stress on coils and lower energy wasted on ignition, leaving more energy available for sustaining the arc phase. See blow how the voltage across plugs looks like, to understand difference between ignition voltage and sustained arc voltage (cylinder #2 has a worn plug, with increased gap):

http://www.globaldenso.com/en/products/aftermarket/plug/power/features.html

 

[koda2000]

okay guys, what's the consensus on this one:

i've heard people say you should never re-gap platinum plugs because you'll damage the platinum tip, which is just a coating and can be worn off.

i believe you need to at least check the gap and, if necessary, reset it because even plugs that come pre-gaped can be bumped during shipping and handling. in the case of the Autolite Double Platinums i recently purchased for my 5.0, i found they were gapped incorrectly for my application. i re-gapped them checking the gap with a ramp-style plug gauge, being careful not to damage the electrode or ground strap tips.

after gapping, a dab of antiseize on the threads, torque to spec and dielectric grease in the boots and it should be good for another 90-100k.

 

[Dono]

Sonic67---Thank you.
I started researching, and my next plug will not be the AR103 racing plug. There are far better alternatives for me out there since my truck is a daily driver. I obviously had no clue.

For me, the XP605's are iridium, and are still heat range 5, cooler than stock and long lasting.

original OP, thanks for starting this thread, I learned something, and you now have far more info than you asked for.

edit: Koda, thats exactly what I have always done (For what thats worth )

 

[deweyville65]

Because copper is for cars build in 1950, with distributor cap. They didn't have dual polarity sparks. Any car build after 1985 have 'waste spark' system with shared coils for two cylinders. Half of cylinders have inverse polarity spark.


If this is the case, how come my 03 Dodge Dakota 4.7 V8, AND 02 GMC 6.0 had a coil for each spark plug. The Dodge was coil on plug, the GMC was coil near plug.

 

[SoNic67]

Coil on plug is a newer system, with double number of coils compared with waste spark system.
And still no distributor and still they don't use copper tips anymore either. Don't need dual platinum, but fine-tip iridium (or platinum) - to lower the voltage stress on the coils that are now smaller then previous ones.

 

[bluestream1]

http://www.youtube.com/watch?v=tS4MV2pELyU&feature=related