Heresy! Replaced NGK Platinum w/Champion Copper Plugs

[Chip Hedrick]

I did the above this weekend at 104,152 mi.

 

The NGK plugs had been in the car for 44,560 mi.

 

The center electrodes on two of the NGK plugs were very worn.

The gaps on the removed plugs were: #1 = 0.047"; #2 = 0.045"; #3 = 0.045"; #4 = 0.048". The spec in the Haynes manual is 0.043". (The plugs otherwise were in excellent condition, which indicates the engine is doing well.)

 

I had to buy a new spark plug gauge because the two I had only went up to 0.040".

 

The dealer charged me $12.50 each for the NGK plugs when they were installed back in 09/07/01. The Champions cost $1.69 each.

 

I gapped the Champions to 0.044" per the recommendation provided by the computer at the NAPA store where I purchased them.

 

HOLY HORSEPOWER!! I must have gained back at least 10 HP, probably more, by installing the Champion plugs.

 

Subaru claims that the service life on NGK platinum plugs is 60,000 mi, but at what loss from original performance?

 

I plan on sticking with the cheaper copper plugs and replacing them every 1yr or 12,000 miles. I suspect I'll keep more HP and better fuel mileage with this strategy.

[edrach]

You might have gone with the cheaper NGKs also. But you seem to have solved your problem. I generally replace my cheap NGKs every 30K whether they need it or not.

[Chip Hedrick]

My original mission was to buy plain copper NGK plugs, but the biggest NAPA store in the area didn't have them (my wife was with me and she wouldn't tolerate going from parts store to parts store on a hunt for the perfect spark plug).

 

So, I went with the Champions. I heard that some EJ25s (the 2.5 RS I think) came from the factory with Champion plugs.

[Nug]

Spark plugs are like oil. It doesn't really matter what you put in there, as long as you replace it occasionally.

[myles]

I heard that some EJ25s (the 2.5 RS I think) came from the factory with Champion plugs.

 

My '02 Legacy GT came with Champion spark plugs.

[Strakes]

My 2002 GT came with Chumpions and developed a misfire (and rough idle) at about 16000 miles and I replaced them with NGKs and haven't had a problem since. I got a whole set of NGK V-power copper cores at O'Reilly's Auto Parts for 6 bucks. Really cheap fix...and it even resulted in an increase in mpg's.

[Chip Hedrick]

Strakes: Your post suggests to me that by 16,000 mi copper plugs may be shot.

 

My theory is that if you're willing to change your plugs every 12,000-15,000 mi you're better off with copper plugs, both because they are a better conductor and they cost less.

 

If you go longer than that between plug changes, you certainly are better off with platinum plugs because they are more durable. But based upon observation of my EJ25, platinum plugs won't give you anywhere near peak performance or peak MPG if you leave them in for 60,000 mi. I suspect 30,000 mi is a better change interval for platinum plugs.

 

60,000 mi plug changes seem to be the equivalent of 7,500 mi dino oil changes: they're minimal maintenance for people who aren't very enthusiastic about keeping their cars in peak shape.

[99obw]

I find this very interesting. I have run the platinums out to 60k twice now, and I never saw a decrease in performace or mileage. When I put the new ones in, no change. What could I possibly be doing different? I have the last set I pulled, perhaps once I tame the jungle that is my lawn I will measure the gap and post it.

 

If I was going to run a cheaper plug I would use NGK V-Power.

[Chip Hedrick]

Two of the platinum plugs I pulled had severely worn down center electrodes. The other two looked OK, except for the over-spec gap.

 

I wonder if the plugs may have been incorrectly torqued when installed by the dealer at the car's 60,000 mi service interval. Just an idea: overtight plug draws more heat from the cylinder and leads to excessive electrode wear??

[PAezb]

I had the mechanic throw in the NGK V-Powers on my 2.5 Phase I engine when it was at the dealer for new HGs. I can't say I've notice a performance increase, or decrease, over the 1500 miles I've put on the car so far. The plugs they replaced were the Bosch Platinums +4s with almost 76K on them (63K to 139K). And yes, I've heard the complaints with Subie engines and Bosch plugs. However, mine performed well I thought, with expected mpg for this engine, and the plugs really didn't show any indication that they needed to be changed. Maybe I need more driving time with the NGK coppers plugs. Perhaps the HG job negated the performance increase I should be noticing with the new plugs, I just don't know. I'm glad that I've got new plugs installed and won't have to worry about them, for another >30K anyway.

 

The NGK V-Power were about $3 less than the Bosch platinum, but hardly worth the savings if the performance is unchanged, and replacement interval is half that of the platinums.

 

Wonder what the reason is for Subaru switching to Champions over NGKs in the new vehicles?

[howards11]

I recently had the plugs changed in my 2000 Forester @ 30K miles. I told my mechanic that they were Champions. He didn't believe me until he replaced them. He still doesn't understand why they would use Champions. :-\

He replaced them with NGK platinums.

 

~Howard

[cookie]

in your manual or file what is going on where. If you have excess wear orf say, a white lean condition always happening on one cylinder it can give you a clue if you have problems later. Say you might have a vacum leak in the manifold and the plugs could show you where.

[wrxsubaru]

Ive had good luck with th bosch +4s i just chaged them at around 80,000 miles and they dident show any real signs of wear, and the news i put in were barley noticable.

[legacy2.5]

it is my experience with japanese cars that they dont run as well with champion plugs, think about, the company that makes a brand of vehicle goes through years of testing to find the right plug that works with the engine well. modern day vehicles are not like old american cars that can run on different heat ranges and so forth. platnium plugs give a broarder spark in the cylinder, and a hotter spark which todays vehicles need.

[blitz]

legacy 2.5, modern vehicles do in fact require a plug of the correct heat range just as vehicles 30 years ago did, the difference is the addition of the "copper core" to spark plug technology who's contribution yields a broader effective heat-range by way of copper's thermal (sinking & releasing) properties. Essentially copper-core plugs are less prone to overheating on mountain grades and less prone to fouling around town.

 

I agree with your comment about the Champions, in fact it's almost universal that NGK's trump Champions, but why? I've finally dug-up some technical info that supports and explains what it is that everyone has been subjectively feeling:

 

http://www.lubedev.com/articles/flameout.htm

[netheadbob]

I'm looking for the proper gap for an EJ22 engine (97 Impreza OBS). Not listed in the manual but I recall a range of .039-.043. I installed new NGK's with a gap of .040 and now have a hesitation on low rpm's. Should I reset the ECU to help remedy the situation.

[MorganM]

Bought my EJ22 with some champions in them. Worked awsome for several years! When I went to finally change them they were so old and rusted (from working for so damn long! ) I thought they were gonna break off in there before coming out!

 

I tried several different types of plugs in my EJ22. Only the NGK coppers and the Champion coppers worked well. The others either idled well and reved up roughly or idled rough and reved up smooth. Yes I indeed checked the gap and set it if needed

[Chip Hedrick]

Blitz: The article you cite, although interesting, doesn't mention Champions as "bad" plugs; it only mentions NGKs as "good" plugs. Therefore, it does not support your proposition that NGK plugs are superior to Champions (they may be, but the article doesn't say so or allow someone to conclude so).

 

Nothing said so far explains why two of the NGK platinum plugs I pulled after 44,500 mi appear severely worn or why the car's power and throttle response improved dramatically after replacing the NGK platinum plugs.

 

Legacy 2.5: Remember that at least some Subaru EJ25s come with Champion plugs as original equipment.

 

My argument is not that Champion is superior to NGK or vice versa, only that I suspect that platinum plugs don't last as long as claimed and that if changed frequently inexpensive copper plugs may outperform overpriced platinum plugs.

[swami2806]

Chip: Were the two that were worn the two closest to the firewall? If so, that's normal. Also, platnum will usually last longer, as far as the metal is concerned. But as for spark, platnum will deterrorate just as quickly b/c of deposits. The deposits act as an insolator. So, platnum good until 30k or so and could be cleaned and regapped with still-good metal. Copper would deterorate, so metal must be filed down to good metal and square and regapped---though not worth it for the price of 4 copper plugs!

[sprintman]

I fitted the NGK Iridiums to Outback and Mazda turbo. 30,000kms on the turbo plugs and like new. More than platiunums or copper but worth every cent IMO.

[Setright]

Netheadbob: 1.1 mm - you convert into customary... ;-)

[NOMAD327]

I have pulled plugs from a couple of my Fords at the recommended 100,000 miles and the original Motorcraft platinums looked like brand new and the engines ran as original and still got equal or better fuel economy to new. I pulled a couple of NGK platinums from 2.5 DOHC Subaru's at 60,000 miles and they also looked like new and still performed correctly.

 

Engineers refer to cars (like most newer Subarus) where one coil feeds two spark plugs, and fires every crank revolution as a waste spark ignition system. (There is a wasted spark during every exhaust stroke) Using a single platinum spark plug on such a car will give two rapidly degraded spark plugs for the following reason. 1/2 of the plugs always see a reverse polarity spark. The reverse polarity sparks will cause material to be transferred from the large ground/outer electrode onto the narrow platinum center electrode's exposed end surface. Double platinum plugs have the fine wire center electrode, and have a small chip of platinum attached to the outer electrode. This prevents the transfer of metal and the resulting fouled plug. I would use either conventional plugs or double platinum in a new Subaru. If you have had trouble with single platinum plugs, that is normal behavior for our cars. I have found the correct double platinum NGK for $10 a piece which is pricey, but better than $15 list, and have used Autolite double platinum for $4 a piece and found them to look good and work good so far. (20,000 miles).

 

[subiemech85]

champions were used because they were american, not canadian japan or some other reason due to % of import in an american car

 

champion is bad due to the poor quality of metal used to make the parts that matter

 

ngk is the way to go

[Jovial]

Nomad327,

 

If I follow what you are saying about the waste spark system, newer Subarus would have the front and rear plug on one side fed by one coil and the other side fed by another coil. If the same plug (front?, rear?) always has a reverse polarity spark, material would be transferred from the large, ground electrode to the small center electrode. On the forward polarity spark the material transfer would be from center to ground.

 

In the case of copper plugs, the ware would be uniform due to similar metals for both electrodes. The double platinums would also wear uniformally due to the platinim square on the ground electrode, but they will wear more slowly than copper. With the single platinum plugs you would see more wear in the reverse plugs because the platinum center does not transfer materail as fast as the large, ground electrode.

 

So how do I know if my ignition has this two plug pre coil waste spark system?

[NOMAD327]

Older cars with distributors driven at half crank speed by the camshaft spark only to the cylinder of the moment. The crankshaft sensor fired coil pack type ignitions common on almost all new cars fire the two cylinders opposite each other in firing order at the same moment. One gets a spark when needed at roughly top dead center compression stroke, The other cylinder gets a spark that has no effect at roughly top dead center on the exhaust stroke. On a Subaru the front cylinders are paired in this way, and the back cylinders are paired similarly, but roughly 180 degrees out in rotation. I don't know why the coil pack cannot fire the same polarity to both sides at once, but they generally at least, do not.