Replaced NGK premium platinum at 31,000

[Captain_Klink]

Subaru Impreza 2.5NA, 2008, at 31,000 miles. Bought the Denso 3395 long life iridium platinum. Richard pulled the old plugs out, at the specified maintenance interval... what a shock!!!
the platinum "hockey puck" part on the NGK double platinum - GONE!!! on all 4 plugs. The "factory" gap, on all four plugs - supposedly "pre gapped" at spark plug factory - ALL OVER THE PLACE, ranging from 2 at .042, and 2 at 0.046. this is after the hockey puck is gone, and 31,000 miles of wear. So for those that say: just put in the plug, don't bother to gap them - this proves what I maintain all along - factory gap is garbage, you need to check it yourself. My Denso 3395 were also ranging from .038 to .042, even though Denso says they all should be at least .044 - I gapped all of the Denso to EXACTLY .042, installed with anti seize compound, and the Impreza JUST LOVES IT!!! (Factory "spec" is .044, but I prefer very slightly on the tighter side, for extremely long spark plug life) I cannot believe how smooth and quiet the engine runs, much more powerful than before, according to my butt dyno, and the bride also agrees with my assessment - she cannot believe how easily the engine starts, right on the first crank, and I had no idea that proper spark plugs will make the engine run quieter, but this is according to the bride, and she wouldn't be making it up.

 

[Drew99GT]

Originally Posted By: Captain_Klink

the platinum "hockey puck" part on the NGK double platinum - GONE!!! on all 4 plugs.


On every vehicle I've pulled double platinum plugs out of, I've found the exact same thing.

 

[mechanicx]

Originally Posted By: Drew99GT
Originally Posted By: Captain_Klink

the platinum "hockey puck" part on the NGK double platinum - GONE!!! on all 4 plugs.


On every vehicle I've pulled double platinum plugs out of, I've found the exact same thing.


I haven't seen it on every double-platinum plugs but I've seen it on many to not trust them to not lose the ground electrode platinum tab. I guess even NGKs have the problem. The OP is right you do need to check the gap on new plugs. NGKs can have a .042 gap for an application that calls for .060.

 

[AzFireGuy79]

I have gone away from platinum in everything I own with the exception of my tacoma which used regular copper Denso. Iridium is the only material to consider these days. When you get to this level you cannot tell the difference between NGK and Denso. Both are very good and have worked well in both foreign and domestic in my experiences.

As you might already be well aware, Do Not gap iridium plugs. Im the kind of person that I have enough auto repair to keep me busy for the next coming so playing around with plugs is my last concern. This is where iridium shines, put em in and forget em for about 80K or more. To each his own.

 

[brandini]

I put NGK iridium in my 6 at 30k and all were (to quote a movie) dead-on balls accurate right not of the box.

 

[dkryan]

Iridium plugs? Uh oh, where have I been?

I had NGK platinum plugs in my 2001 Infiniti I30, supposedly good for 105k miles. I pulled them at 58k miles, as much out of curiosity, in addition to my concern I would not be able to remove them after ten years and 105k miles.

Honestly, they looked pretty darn good. I believe they might have lasted 105k miles, but I did not want to find out.

So, who makes the iridium plugs and why are they better than platinum?

 

[ET16]

Originally Posted By: dkryan
Iridium plugs? Uh oh, where have I been?

I had NGK platinum plugs in my 2001 Infiniti I30, supposedly good for 105k miles. I pulled them at 58k miles, as much out of curiosity, in addition to my concern I would not be able to remove them after ten years and 105k miles.

Honestly, they looked pretty darn good. I believe they might have lasted 105k miles, but I did not want to find out.

So, who makes the iridium plugs and why are they better than platinum?



Many makers. They are supposed to last longer.

 

[Bob Woods]

iridium is a from of platinum http://periodic.lanl.gov/elements/77.html

 

[labman]

Not quite. Lithium, sodium potassium and others are all the same family, but different elements. Copper, silver, and gold are another family.

 

[Captain_Klink]

The Denso website explains how to gap their iridium plugs. They warn to be careful about the very tiny brittle iridium tip, and how to avoid fracturing it. The website suggests that the plugs are minimum of factory spec out of the box, and may be even a bit wider, but due to the easy sparkability of the iridium design, a wider gap works well. I found they were a bit tight out of the box, so I had to widen them out a bit. A small gap fires easily, but has a weaker spark. I did not widen them all the way to spec, just .002 shy of spec. I have seen NGK iridium platinum in excellent shape after running 40,000 miles, so I wonder if they have better quality control on the (more expensive) iridium line.
I have used AC Delco iridium, and the electrode seems very well made, and the Autolite XP iridium also seems to be a good plug, but the gap tolerances and electrode alignment are often wonky and need straightening.
So just because some people say not to gap iridium, doesn't mean not to do it - Denso website itself explains how to do it.

 

[JustinC25]

The Denso double platinum's I pulled out of my Camry at 60k looked new. I didn't check the gap though.
I bought these plugs when I did the motor. I got them over the counter at the dealer. I worked there at the time and got them for about 5 bucks each.
I run Denso in both my vehicles. I've yet to see an application that didn't like them. Both my Camry, and my Windstar have the double platinum's, and I just put a set of the TT's in my uncle's Windstar yesterday. I removed the original Motorcraft's at 163k (They had the factory pink & yellow dots) & the gap showed it. BIG DIFFERENCE, It runs much better now, and seems to have more power. (Again this is just the butt dino)

 

[mechanicx]

The thing about iridiums is, I'm not clear that they aren't just iridium cores with platinum tips. I'm getting to think that double platinum or iridium are a bad choice even in an engine that has the wasted spark and require a platinum/iridium tab on the ground electrode since they tend to fall off. Single platinums/iridiums at least will wear slowly and predictably. And yes you can and should check and gap iridium or platinum plugs.

 

[AzFireGuy79]

Some compaines, NGK in the past being one, do recommend NOT gapping iridium. If Denso says ok then gap away. Info can change but traditionally ididiums were not to be gapped. You highlight a good point in that the tips can be easily broken when attempting to gap. Most backyard mechanics would just go at them like a copper plug and break off every electrode in short order.

 

[mechanicx]

I just want to make clear though that the platinum tab falls off of OEM plugs that no one ever regapped. I can't remember if they were NGK or Denso, I get them confused and I don't really think there is any difference between the two anyway, but they can and should be checked/gapped. Platinum plugs are supposed to be gapped with a non-wire gauge and this gauge has the proper gapping atachment design for them. I don't think regapping them has anything to do with the tabs falling off the gorund electrode.

 

[AzFireGuy79]

im not even speaking about platinum. I dont use them. I have but switched to IRIDIUM. They iridium do have brittle electrodes that can fracture if gapped by someone who does not know what they are doing. The reason why some companies warn against it, along with the fact that the tolerances are so tight there is no reason to. But if people want to mess up a perfectly good $8+ plug thats their business.

 

[mechtech2]

If the platinum tip are gone, how come the gaps are not wider?
They are still within the stock range for gap!

Some waste spark ignitions use platinum tips discretionally.
They will be found on the side electrode on half, and the center electrode on the other half.
This is often confused with precious metals dissappearing.
Also, some tips are very small, and get hidden by any deposits.


You may indeed have melted away the tips, but that would not explain why the gaps are not biggger.

 

[mechanicx]

Well like I said or at least meant NGK and or Denso, I'm thinking Denso, iridiums that I've seen are gapable and require gapping. That was my point that iridiums can be gapped too. I'm still not clear if the iridiums are completely iridium elctrodes or not, and just iridium cored with a platinum tip or coating. But I guess that could still make them more brittle than straight platinums and they might stick the the ground electrode better than the straight platinums.

Also if the iridiums have the same ground electrode problem as the platinums, maybe it'd be ahead to use single iridiums too even on a wasted spark ignition.

 

[mechanicx]

Originally Posted By: mechtech2
If the platinum tip are gone, how come the gaps are not wider?
They are still within the stock range for gap!


Yeah when the side electrod platinum tab actually falls off the gap opens up like over .010, not good when you have some plugs with up to a .070 or .080 gap.



Quote:
Some waste spark ignitions use platinum tips discretionally.
They will be found on the side electrode on half, and the center electrode on the other half.
This is often confused with precious metals dissappearing.
Also, some tips are very small, and get hidden by any deposits.




This makes sense since one plug will always be firing in "reverse" as far as I know, but I don't think I've seen this discretionary plugs, not with ACDelco originals or replacements nor most other service plugs. The plugs are all the same and don't have specific cylinders they go into. Who does this half and half? But it's not going to necessarily stop the tab from coming off the plugs that have a platinum tip and fire from the side electrode. But either way, like you said when the tab falls off the gap opens up.

You know what I just thought of something. It seems like the platinum tabs only fall off on certain cylinders. I haven't kept track of if it's always the same ones or not, and I don't really know if they are the cylinders the plugs are firing in reverese, but I'd think it might be the ones that are firing in reverse that are more prone to lose their side electrode tab, and need the side electrode tab in the first place. It'd be interesting to know. I haven't seen the tab come off the center electrode.

 

[mechtech2]

Correct - Replacement spark plugs have tips on BOTH sides.
It is the factories that use one side or the other.
And it is factory plugs that people often accuse of 'losing' their tips.

 

[mechanicx]

Originally Posted By: mechtech2
Correct - Replacement spark plugs have tips on BOTH sides.
It is the factories that use one side or the other.
And it is factory plugs that people often accuse of 'losing' their tips.


OK but I'm accusing AcDelco platinums originals which do have a side electrode tab of losing their tip (and increasing gap) and the replacement being the same situation. So I know it really happens. In other cases where the originals didn't open the gap up and appear to have a missing tip then what you're saying would be true.