Spark plugs

[tbm3fan]

I'm curious about type not make. Such as copper vs platinum vs iridium. Reason being there has been a long discussion on my Focus forum about swapping out the Motorcraft platinum for copper due to greater conduction of the spark. Platinum lasts longer but copper conducts better and the recommendation was to try those and open the gap 0.50 to 0.55.

Well I tried it on the Mazda 626 which always ran the platinum NKG. For the 8 years I have had the car it always seemed to resist going above 70 mph. Needed some throttle pressure to move it past that point. After the copper plugs went in the pressure needed disappeared and the car soon was up to 80 without a complaint. Hugh difference here.

The Focus was next. The large 2.3L engine has a very strong power band starting at 3000 rpm particularly if you have a stick. Very quick and a good exhaust note out of the stock exhaust. Well copper plugs noticeably gave more oomph to a full throttle acceleration. The rate that the car can go from 60 to 100 was a bit faster.

Anyway, since the Dodge has a high performance electronic ignition I thought I'd remove the Champion Platinum plugs and try copper while opening the gap this weekend. Thinking of gapping @ 0.040 to see the result. I have no issue replacing them often which for a car driven a 1000 miles a year is not to often.

 

[cantflip]

I'm curious about type not make. Such as copper vs platinum vs iridium. Reason being there has been a long discussion on my Focus forum about swapping out the Motorcraft platinum for copper due to greater conduction of the spark. Platinum lasts longer but copper conducts better and the recommendation was to try those and open the gap 0.50 to 0.55.

Well I tried it on the Mazda 626 which always ran the platinum NKG. For the 8 years I have had the car it always seemed to resist going above 70 mph. Needed some throttle pressure to move it past that point. After the copper plugs went in the pressure needed disappeared and the car soon was up to 80 without a complaint. Hugh difference here.

The Focus was next. The large 2.3L engine has a very strong power band starting at 3000 rpm particularly if you have a stick. Very quick and a good exhaust note out of the stock exhaust. Well copper plugs noticeably gave more oomph to a full throttle acceleration. The rate that the car can go from 60 to 100 was a bit faster.

Anyway, since the Dodge has a high performance electronic ignition I thought I'd remove the Champion Platinum plugs and try copper while opening the gap this weekend. Thinking of gapping @ 0.040 to see the result. I have no issue replacing them often which for a car driven a 1000 miles a year is not to often.

You've hit on two thing at once here... First, copper, a softer metal will "fragment" when fired... Tiny particles of burning copper blown off during every firing event, which is also why they wear over time.

Second, the wider gap increases spark intensity... basically more voltage roughly= more amperage... or simply a hotter spark. The two major concerns with this would be getting the plug too hot, at the first sign of "ping" you've gone too far. That might show in hot weather or after a fresh tank of gas. Or you could have secondary ignition problems develop. Your secondary ignition insulation is only as good as the weakest part, so when you increase the resistance by opening the gaps... you are pushing for the next weak bit to allow the spark to find ground outside of the combustion chamber (misfire).

Because the factory had to workout a setting that was as close to universal as possible and they needed the parts to last for a reasonable interval... factory specs may offer some room for improvement. BUT, when you do stuff like this, expect short life from components of the ignition and realize that even a change in the weather may cause you some problems.

Platinum and Iridium are popular because the manufacturers have to provide a very long emissions warranty, their valuable and harder material (compared to copper) won't fragment and show wear/change the gap as they age. They also have a chemical reaction with hydrocarbons at high temperature where they will cause the fuel to burn, this makes them capable of burning themselves clean if fouled. Platinum was used to do the same reaction inside your catalyst... until it was (mostly) replaced by palladium to do the job.

p.s. If your car had a carbon buildup in the combustion chambers, you may find a little less change once it has burned clean.

 

[Carmine]

My experience with platinum plugs in older cars has never been good. Always went back to copper.

 

[Yatzee]

I'm curious about type not make. Such as copper vs platinum vs iridium. Reason being there has been a long discussion on my Focus forum about swapping out the Motorcraft platinum for copper due to greater conduction of the spark. Platinum lasts longer but copper conducts better and the recommendation was to try those and open the gap 0.50 to 0.55.

Well I tried it on the Mazda 626 which always ran the platinum NKG. For the 8 years I have had the car it always seemed to resist going above 70 mph. Needed some throttle pressure to move it past that point. After the copper plugs went in the pressure needed disappeared and the car soon was up to 80 without a complaint. Hugh difference here.

The Focus was next. The large 2.3L engine has a very strong power band starting at 3000 rpm particularly if you have a stick. Very quick and a good exhaust note out of the stock exhaust. Well copper plugs noticeably gave more oomph to a full throttle acceleration. The rate that the car can go from 60 to 100 was a bit faster.

Anyway, since the Dodge has a high performance electronic ignition I thought I'd remove the Champion Platinum plugs and try copper while opening the gap this weekend. Thinking of gapping @ 0.040 to see the result. I have no issue replacing them often which for a car driven a 1000 miles a year is not to often.

Having used all three types of plugs, I'd have to conclude that Platinum and Iridium plugs are far superior in many ways. These plugs last longer and generally speaking are pre-gapped right out of the box for their specific heat range, which is pretty much non existent in Iridium. I agree totally with "cantflip" on the downfall of copper plugs. Surprisingly to many here I use Motorcraft platinum almost exclusively and have never had issues with them and my ignition system is a CD style distributor using a CD, High Output, E-Core coil for the last three years. You need to be aware that a good ignition system is comprised of more than just the plugs. Coil, wires, and distributor condition can make a world of difference in overall performance and mileage. Try different types of plugs over your next three changes then judge for yourself which ones best suit your needs and budget.

 

[tbm3fan]

Having used all three types of plugs, I'd have to conclude that Platinum and Iridium plugs are far superior in many ways. These plugs last longer and generally speaking are pre-gapped right out of the box for their specific heat range, which is pretty much non existent in Iridium. I agree totally with "cantflip" on the downfall of copper plugs. Surprisingly to many here I use Motorcraft platinum almost exclusively and have never had issues with them and my ignition system is a CD style distributor using a CD, High Output, E-Core coil for the last three years. You need to be aware that a good ignition system is comprised of more than just the plugs. Coil, wires, and distributor condition can make a world of difference in overall performance and mileage. Try different types of plugs over your next three changes then judge for yourself which ones best suit your needs and budget.

My four older Fords have always run Autolite BF42 plugs and never have had anything else. So I can make no comparison to any other plug. The Mazdas have always run platinum plugs and so has the Focus so I had no comparison the other way. Longevity is not an issue for me not with 160 BF42 plugs and the other Autolites cheap at $1.10. Now all the Fords run Pertronix 2 along with a Pertronix 2 coil. Mazdas the stock electronic ignition as is the Focus at coil over. At the Focus Duratec forum, which has page after page discussing this, the general consensus is that using copper led to better response and a slight increase in mpg. I can attest to the performance and have to wait on the mpg. Have to wait on the Mazda for mpg also. Since the Focus was so positive I quickly put in iridium as they also have the high conductivity. Mazda will stay at copper gapped .004 larger as that car only gets 3-4000 miles per year.


The Dodge has never had copper plugs since I have had it and now will make the change to see the effect. It has Pertronix 2 along with the high output coil so it should be interesting. Plenty of electrical power. If an improvement the copper will stay since 1000 miles a year doesn't pose a longevity issue. Given that I don't feel the slightly wider gap will cause problems and I don't have any weather issues out here. The Dodge will be tested out this weekend.

 

[70NEWYORKER]

I've been using the copper Champions since they came out in the early 80's. They may wear faster then the high zoot space age stuff, but with the price difference I can change them several times and still be ahead financially.

 

[tbm3fan]

The Focus has been interesting these last 6 months. It maybe a 2004 but to everybody it looks brand new in and out, trunk and engine compartment. Always trouble free. Then six months ago I could feel a slight roughness in the idle at a light in the seat of my pants. A few months later I could now see a slight fluctuation in the tach needle. The car also exhibited a stumble/bogged if you use too much accelerator versus a gradual increase.

Checked out if anybody had something similar and yes a lot have. Turns out a crack forms in the pcv hose creating a vacuum leak. Problem is the hose is under the intake manifold which means it has to be removed to get at it. At the very least the fan assemble needs to come out although some remove the radiator also when lacking correct tools for the tight space. Great! Then 2 1/2 weeks ago the car threw a code for misfire. So I parked it for two weeks to get the damn hose and find the time to start the process. When time came the new battery was dead. Yep, forgot about the Focus dash light gremlins that show up after the car is turned off in the colder weather. Charge the battery, run the car, engine light off, coppers in. Did fine enough that I put iridiums in and prepared to do the hose this Sunday.

While driving Tuesday the ECU had time to run a few cycles and threw a code again. Didn't drive Wednesday but did yesterday. Start the car in the morning and it started easily. The idle settled down and was quite smooth. Huh? Look at the dash and the code is gone. Drive the car all day and the idle through the seat of my pants and the tach are steady. The bog almost all gone. WTH! Either way the pcv hose and all intake vacuum lines are going to be replaced.

 

[CBODY67]

As for the "copper" spark plugs, that copper is in the center, enclosed conductor of the plug, NOT on the outside or near the gap. You'll need to find an exploded-view illustration of the plug to see just where it is.

Champion did a promotion in about 1963 of how their plugs performed against OEM plugs in a drag race start. The Champion-equipped car always won. THEN it was discovered that the particular plugs they used were "commercial" plugs, with an internal gap inside the plug. This "commercial" plug had that gap to add to fouling resistance characteristics. How? That extra gap inside the plug made the coil have to build up more voltage to jump it and get the energy to the spark plug gap for firing.

I remember when the "superior at the time" copper plugs came out. I don't remember any specific reason, at that time, that made them a better choice. other than possibly the better conductance of copper itself.

How long the gap lasts is a function of the materials in the center electrode and the ground electrode.

In a modern emissions-controlled engine, having the spark jump correctly EACH firing cycle is important. No more important than it ever has been in prior times, but more important with everything else in the combustion process being more consistent and optimized for best operation/performance.

Widening the plug gap results in making the coil build to a higher voltage to fire the plug, as long as the voltage needed CAN get there, with total coil output and the condition of spark plug wires being important.

Using the "conventional gap" plugs, you can help things by doing one of two things. Snip the ground electrode until it only covers 1/2 of the center electrode's width. Then dress it all nice with a point file and gap to whatever you desire. This was used on Champion racing plugs in the 1960s, called "J-gap" plugs (NOT to be confused with the J-__ plugs' part number/heat range. This exposes the flame kernel to more of the mixture. Check out the NGK V-power illustration for more information. The other thing you can do is gently rotate the ground electrode so that it only covers 1/2 of the center electrode. Same flame kernel exposure, just a different way of getting there.

CBODY67

 

[RJRENTON]

Gentlemen,
I agree totally with Goodbody.....i have almost always used Champion plugs but have experimented with other designs and manufactures. I've had good luck with....AC R43S...and modified the ground electrode by grinding it back to a "V" configuration half way across the center electrode (this provides a bigger flame kernel for a better chance to light the fuel charge).... plus they are cheap. I'm presently using Champion UJ-11G (small diameter center electrode made from plainium and gold alloy NON projected nose) and sometimes Champion HO-8A (small diameter center electrode made from platinum also NON projected nose)....very broad heat range...great for racing. These were originally developed for 2 cycle Homelite racing go cart engines running an alcohol/nitromethane/castor oil fuel mix. ..very rare but can be found on eBay reasonably priced, (Most people fo not know they exist)....and they last a long time. For a stock engine/daily driver Champion RJ-12YC will work just fine...also consider Autolite AP85 (platinum alloy center electrode projected nose) cheap, readily available ($2-3 each). These are resistor plugs broad heat range. My comments are based on a 440 (383) RB/B engines using 3/8" reach design. LA engines use 3/4" reach plugs. This of course, is just my opinion....the NGK proponents will have their own opinions....which brand and type and heat range must be determined my the owner.
Bob Renton