Denso IT20'S after 12k comparison

[CRUZTAKER]

http://www.mercurygallery.net/mmnet/watermark.php?file=503/627IT20_PIC-med.jpg


I replace my Denso IT20's the other day. I thought it might be interesting to share the difference between a new one, and one with 12,000 miles. The used one I chose for the pic, was by far the worst, almost no center conductor remaining.

Pardon the pic quality, I had to doctor some shadowing. Not easy taking a close up of something so small with a standard 35mm lense.

[FordNut]

Amazing... Feel any different after replacement? I thought the iridium plugs were supposed to last a long time. WTF...

[TripleTransAm]

Which cylinder did you pull that one from?

[TripleTransAm]

Originally posted by FordNut
Amazing... Feel any different after replacement? I thought the iridium plugs were supposed to last a long time. WTF...


Agreed, I pulled over 40000 miles on stock AC Delco platinums in my LS1 with a variety of usage, from sustained high-RPM (road course lapping) to drag to light throttle highway, etc... you name it. And they were worn, but probably could have gone another 15000+ miles without any obvious degradation of performance.

And I thought the iridiums were supposed to outperform the platinums!

Could be that this car is running overly lean?

[CRUZTAKER]

I was always aware that these plugs have a short life span, say under 15k. I was warned, so it wasn't a surprise.

As far as which plug...? I know it was passenger side. I can't remember which. Second or third from fire wall?

#8 had taken water from a leaky coil cover and become rusty, and the boot was discolored. Watch out for this issue.

[Lowell]

Keep track of the plug location in the future. They can tell you a lot of information about your engine.

[SergntMac]

Originally posted by Lowell
Keep track of the plug location in the future. They can tell you a lot of information about your engine.
Please?

Barry, have you checked your AFR?

[TripleTransAm]

Originally posted by CRUZTAKER
#8 had taken water from a leaky coil cover and become rusty, and the boot was discolored. Watch out for this issue.


Interesting... I'll have a closer look at that. Would it be leaking from factory or from improper re-installation when changing plugs?
(come to think of it, my driver's side HAS been off recently...)
Thanks for the heads-up...

I was unaware of the short lifespan issue with these plugs of yours. Also interesting to keep in mind...

[WolfeBros]

Holy sparkplug Batman. Makes me want to check mine too.
I probably have 9k on my Denso's.
I heard they were lower life but that is kinda alarming to me anyway. Thanks for the heads up Barry.

[SergntMac]

I'll take the Denso longevity in stride, more "smiles per mile" than others. But, I want to know more about the coil cover's ability to seal out weather. I hope to know more soon.

[Marauderer]

Have you ever heard any detonation mild or otherwise (mild - marbles in your engine, severe - a tinny sounding machine gun) cause this is a sign, especially if there is pitting. Maybe in 4th gear, up a hill under light to medium load? If not, I'm amazed they wore so quickly, you must have a Lead Foot!!!

Also, Lowell was right, location info is very important when tracking down problems! I always take mine out and lay them in order or number them with a sharpie.

Like the others asked as well, have you checked your A/F on a dyno after the chip and headers?

[schuvwj]

Originally posted by CRUZTAKER
http://www.mercurygallery.net/mmnet/watermark.php?file=503/627IT20_PIC-med.jpg


I replace my Denso IT20's the other day. I thought it might be interesting to share the difference between a new one, and one with 12,000 miles. The used one I chose for the pic, was by far the worst, almost no center conductor remaining.

Pardon the pic quality, I had to doctor some shadowing. Not easy taking a close up of something so small with a standard 35mm lense.

Hey CRUZTAKER, did you gap the new Denso's?
When new my Denso gaps ran a range from 0.030" to 0.045". I found by gapping these plugs about 0.052", being very careful not to apply any pressure on the center electrode, my MM ran much better!

Have a Good One!

[BillyGman]

gapped mine to at .055".......

[jgc61sr2002]

It was my understanding that Dennis R. stated that the plugs were pregapped and install them as they come.

[Marauderer]

If your conditions are normal, then I guess this is all wrong :)



Iridium is the king of spark plug metals. It has strength and melting temperature far higher than even platinum. The high melting point means the center electrode can be made even thinner - 0.4mm on the Denso plugs we sell (see picture). The longevity of these plugs is unsurpassed. Iridium is so hard that the electrode must be welded on using lasers; this process, plus the scarcity of the metal, contributes to the plugs' high price. But no plug will last longer than an iridium one.

[CRUZTAKER]

No abnormal detonation. The car ran fine up until I replaced them.
(I did however notice my 1/4 mile time lower than other folks with my setup, and closer to stock cold weather times)
I will say however, I made the mistake of gapping the first set. Dennis later made it very clear......don't gap these plugs...just put them in.... This new set was installed as is.
Perhaps I goofed them from the get go.
As far as a lead foot...yes. All the time. I am very hard on this car. Afterall, it's hard not to be!

As far as Iridium being long lasting....I dunno? Dennis is the one who told me that they should last about 15k depending on driving habits.

As far as my car running lean....probably. I don't have the luxury of getting the power tune. And my tech at the dealer has no clue how to re-tune the car to it's new standards.
This is exactly why I am trying to schedule a power tune with Jerry at my local Dyno shop for spring 2004. I need it bad. So bad, that I am willing to drive to Detroit next time you folks schedule one.

Let me reiterate...this was the worst plug of all, most were only worn down 2 mm. compared with new.

[TripleTransAm]

Originally posted by schuvwj
When new my Denso gaps ran a range from 0.030" to 0.045".


These are plugs you're supposed to install without gapping them?????

[CRUZTAKER]

DEEENNNNIS!....where are you?

[FordNut]

When I put in my IT20s I checked the gaps but they were all the same so I didn't adjust them. Don't remember what the gaps were. It's been over 15k, so maybe I should take a look at them.

[Dennis Reinhart]

The plug is under waranty if bought from me and I would also like to know what cylinder this came out of