Why do people use cheap copper plugs still?

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Per manual....my 03' Focus suggested changing the double-platinum at 100K.

I got around to it at 104K....and when I removed them....all four still looked good.

Replaced the with Autolite Double-Plat (APP 103's).....which have been working beautifully ever since.

The Autolite AAP 103's (Double Plats) cost me $4.49 each at O'Reileys....but they had a $1.50 per plug rebate from Autolite....thus costing me $2.99 each. Pretty good price for the next 100K.

Why change coppers every 30K....when you can go 100K with double-plats... Saves time and $$$$.
 
In my Family's Taurus's they all come from the factory with double platinum's.
When I have done tune ups due to mis-fires I replace the plugs-wires and power pack.
On each of the Taurus's I have worked on the plugs looked fine at 90,000-100,000 miles since the last tune up.
I just figured that it was probably the older wires or power pack, but since I was there I would do the plugs too.

This makes me wonder if you could go longer than 100,000 miles on platinum's in that old Vulcan SOHC engine. However, I'm not sure if I want to be the lab rat on that one.
 
Originally Posted By: AandPDan
I use copper plugs because they are OEM.


That's the case with my F-150 and my old Audi. So, I stick with the original. If it specified something else or was really difficult to change, well, I'd consider something longer lasting, for sure.
 
California wants you to be able to go ~100k before your first tune up for smog reasons. Driving force behind platinum/ iridium.

I'm still from the school... probably a decade old school... that copper runs/ conducts better than platinum, and its only downside is faster wear. But jeez I'm happy to have them out just so they don't get stuck in there.

I also suspect if one is buying platinum plugs in blister packs at walmart they could wind up getting something off a heat range that's trying to cover too many part numbers in the catalog and will have less than optimal performance b/c of that...
 
Originally Posted By: tomcat27
"easy to replace" is relative. I spent a couple hours replacing the OEM coppers in my 05 Durango Hemi. 16 plugs total. and most of the engine is behind the hood. really slow process. of course I replaced with plats.


My favorite example!

#1 it is a complete myth that "copper" (they're not really, just the core) plugs make more power or somehow 'run' better. New ZL-1 camaro? Plat/iridium. New Stang? Plat/iridium. If they made more power the mfgr's would use them. The reason they ship with coppers is they are CHEAP and it gets you back in for service sooner.

The 5.7 Hemi owner above had copper plugs. 16 new Plats and he's running fine. Note that my 6.1 is virtually identical but ships with NGK plat/iridium plugs.

Choose your plug by how often you want to fool with it.
 
The plugs were covered in rust on the threads from being in there so long, definitely had more than 4,000 mi put on them (i bought it with 168k on it, it has 172,900 on it now)

The car tells me this about the owner:

1: he overloaded the factory electrical system with an upgraded stereo, fuse box-battery connector is an aftermarket one. Alt, battery, and starter are pepboys units, reman for alt/starter.

2: he put more money into the stereo than the engine, Infinity Ref Series speakers, and a disconnected factory radio control unit, with cut wires that i had to splice back.
 
Originally Posted By: Bamaro
What plug material conducts electricity better than copper?

When the plug is hit with 10-25K volts from the iginition system, a .1 ohm difference in plug resistance(conductivity) is meaningless...
 
Copper doesn't last. Here are the melting points of some commonly used metals (Celsius):

Zinc == 420
Aluminum == 660
Copper == 1083
Steel == 1400-1500
Platinum == 1772
Iridium == 2410



Here are the thermal conductivities of some commonly used metals (Watts / centimeter*Kelvin):


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


As you can see, copper is pretty much unbeatable for thermal conductivity.
 
the original Saturn 1.9 doesn't work very well with anything but copper, NGK is factory. lots of people put iridium magic metal plugs in thinking they are going to get more power, but it runs worse.
the '93 Camry I'm driving now, I helped out the previous owner by doing a tune up for her, I used NGK copper and new wires. it ran great. a short time (few months) she was having starting/idling issues and the garage she brought it to did a full tun up AGAIN, replacing the relatively new plugs w/ platinums or whatever ($16/per!) and new wires (over $100!)
still didn't run right.
when I got the car, I traced the problem to a clogged EGR.
been driving it almost a year now, no problems, but I do wish I had the copper NGK's I put in there...
 
because a lot of engines cam factory with copper plugs.
copper is the best conductor. Some engines will trigger cell codes and run like [censored] with platinum and iridium.

lastly I would rather swap plugs every 30 K knowing they wont be seized in the head versus rolling the dice I can get them out at 100K.

BTW in all my 4 cylinders I can swap the plugs in about a 1/2 hr max.

Originally Posted By: hattaresguy
I'm surprised people are still using them. I don't like to make work, so I really like those super duty modern Iridium plugs than can got 100k or 200k miles in some cases.

Why do something several times over the life of the engine, when it can only be done once or twice?

OTOH copper plugs are great in pre 90 German cars.
 
Originally Posted By: VNTS
because a lot of engines cam factory with copper plugs.
copper is the best conductor. Some engines will trigger cell codes and run like [censored] with platinum and iridium.

lastly I would rather swap plugs every 30 K knowing they wont be seized in the head versus rolling the dice I can get them out at 100K.

BTW in all my 4 cylinders I can swap the plugs in about a 1/2 hr max.

Originally Posted By: hattaresguy
I'm surprised people are still using them. I don't like to make work, so I really like those super duty modern Iridium plugs than can got 100k or 200k miles in some cases.

Why do something several times over the life of the engine, when it can only be done once or twice?

OTOH copper plugs are great in pre 90 German cars.



This. My Jeep 4.0 will misfire and make the dash light up like a christmas tree on anything but copper plugs. The more electrodes the plugs have the less cylinders it will run on.
lol.gif
 
I've heard all the above.

Funny, in all the cars that rolled through my driveway I've never experienced it. Back when I had a 98 Neon R/T I was cautioned against using anything but coppers. I used fancy platinums, it ran like a banshee for years until stolen. 36 mpg in that little rocket!

People used to say the 5.7 motors from Chrysler wouldn't run right on anything but copper cores, and that's been proven complete baloney.

I'm sure that some of you guys are having real experiences but it just doesn't jive with me and mine.
 
Id agree that Ive never seen a real difference... im running autolite iridium plugs in my chevy truck and will be putting them in our VW soon! Different materials, oh no!

Ill bet that if the gap is maintained longer, that the use of Pt and Ir plugs in many applications has more to do with keeping emissions in spec than anything else. My cars, which have Pt plugs, all seem to ask for a 40k replacement even though they are Pt! They have always looked like new coming out!

But in my 4cyl cars Im really tempted to just use Cu because of the low cost considering how cheap/easy they are to replace on those cars. That said, Im a bit wary to be a guinea pig of how much more the Cu plugs degrade over the 30-40k vs the longer life plug designs...
 
The waste spark ignition system in German cars of the 80's and 90's depending on the engine didn't always do well with Platinum plugs because the electrode is a bit thicker.

Fast forward to 2012 and I can't imagine any manufacture using copper plugs unless they are cheap. Modern engines and ignition systems are very clean and all plugs should almost be lifetime.
 
Only iridium I would ever recommend running is the Denso one that has a 0.4mm tip. Sharpest you can find.
 
I put Bosch Platinum plugs in my '85 Volvo 240 (intercooled turbo, K-Jetronic) and it ran worse than it had with worn copper plugs. replaced cap & rotor at the same time. Figured I must have damaged a wire while changing plugs, so replaced the wires. Still ran worse, not awful, but noticeably worse.

Changed back to copper core plugs and lo and behold, it ran better than on the Platinums.

Can't explain it, but that B21FT (Red Block for the Volvo nuts) liked copper better...
 
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