[7thgen]

B24 just showed up on the maintenance minder today, so I started looking into spark plugs. I know the topic has been beat to death and I see a bunch of older posts saying use the original NGK or Denso no matter what. But Denso has a fairly new product called Iridium TT. Denso claims it offers advantages in economy and power over long life iridium and lasts well over 100,000 miles. Sounds too good to be true, but is it? I'd love to put "new & improved" into my old car instead of 10+ year old technology... if it is truly improved and not just new.

Does anyone have any experience or advice regarding Denso IK20TT in an I-4 7th gen? If you're using them, did gas mileage improve? Is the gap difference of .040 vs .050 on the original plugs something to be concerned about?

 

[jimijam]

What does their marketing gouge provide in the way of evidence of those so called "advantages" in power? How about economy?

I am a firm believer that just because a plug may last 100K miles, doesn't mean you should leave those in your head(s) that long.

 

[t-rd]

IK20TT works fine and I've been running them. Before that, I've been running the IK20 iridium power and I change them every 30k miles. I never use iridium long life, other than the OEM set I swapped out years ago.

 

[7thgen]

What does their marketing gouge provide in the way of evidence of those so called "advantages" in power? How about economy?

I am a firm believer that just because a plug may last 100K miles, doesn't mean you should leave those in your head(s) that long.

LOL, I don't think I saw any actual numbers. I'd guess about a gallon of gas and 5 minutes of travel time over the life of the plugs :grin

IK20TT works fine and I've been running them. Before that, I've been running the IK20 iridium power and I change them every 30k miles. I never use iridium long life, other than the OEM set I swapped out years ago.

Good to know, thanks. I considered the iridium power too, but no way I'm putting 30K plugs in my head, even if they save me 10 minutes of travel time.

 

[t-rd]

30K miles is the recommended change interval for non-long life plugs by Denso.

 

[Drew03Accord]

I am a firm believer that just because a plug may last 100K miles, doesn't mean you should leave those in your head(s) that long.

Although many (including the plug manufs) say you don't need antiseize, I always use the high temp copper stuff on my plug threads. In doing so, I have no qualms leaving them in that long. I used to pull them halfway through and check with a gap tool, but found there was really no need. The only negative on using the antiseize, is those who don't understand how it changes the torque specs. I torque by feel when installing plugs. I know this sounds crazy, but I trust that more than blindly following a torque wrench in such a $en$itive area.

 

[ypsibird]

The only negative on using the antiseize, is those who don't understand how it changes the torque specs.

The torque specs in the factory service manual for the plugs are for the use of anti-seize. People that don't use anti-seize are the ones that need to understand how it changes the torque specs!

 

[jimijam]

I've probably changed more spark plugs that some of the members here have change their own underwear. I have NEVER used a torque wrench for spark plugs on any car, motorcycle, or truck that I have owned. I have never had a problem. I never will.

 

[qman]

+2 that here brothers. I only use the torque wrench for lug nuts and important engine bolts.

Speaking of underwear . . . I have socks older than my kids.

 

[scar_cle]

B24 just showed up on the maintenance minder today, so I started looking into spark plugs. I know the topic has been beat to death and I see a bunch of older posts saying use the original NGK or Denso no matter what. But Denso has a fairly new product called Iridium TT. Denso claims it offers advantages in economy and power over long life iridium and lasts well over 100,000 miles. Sounds too good to be true, but is it? I'd love to put "new & improved" into my old car instead of 10+ year old technology... if it is truly improved and not just new.

Does anyone have any experience or advice regarding Denso IK20TT in an I-4 7th gen? If you're using them, did gas mileage improve? Is the gap difference of .040 vs .050 on the original plugs something to be concerned about?

I just replaced what I believe to be the factory plugs in my I4. Put in exactly what I pulled out. Factory plugs had almost 11 years or 159,xxx miles on them. (can search my posts for photo) I dont recommend waiting that long, but given the excellent wear of plugs that came in the car, that is exactly what went in to replace. I would highly recommend using what came out, nothing else.

 

[ltfa182]

I agree with you ^^

I considered the iridium TTs myself, but at 160k the OEM plugs looked pretty decent. I just went with NGK OEM replacements. If you’re only going to change it every 100k then just put in what works...at least that’s my thinking

 

[Drew03Accord]

Factory plugs had almost 11 years or 159,xxx miles on them. (can search my posts for photo)

Did you happen to check the gaps when you pulled them out? I just did the plugs in my truck (V8)and all had increased gaps, except #5, which was still gapped perfectly. The electrode also looked a lot newer than the rest with no sloping of the metal. Even the porcelain was cleaner. Makes me wonder if that coil pack has grown weak. Might swap it out soon. I used NGK V power copper, which only last for 30K, but I ran them for 40.

 

[scar_cle]

Did you happen to check the gaps when you pulled them out? I just did the plugs in my truck (V8)and all had increased gaps, except #5, which was still gapped perfectly. The electrode also looked a lot newer than the rest with no sloping of the metal. Even the porcelain was cleaner. Makes me wonder if that coil pack has grown weak. Might swap it out soon. I used NGK V power copper, which only last for 30K, but I ran them for 40.

Gaps were all within specs. I did measure them. (think its .45, or .44) If you search my posts you can see the photo of what I took out and for the age and mileage, I feel these plugs held up VERY well which is why when it was time to replace, I put in exactly what I took out. Figure im good now for the rest of the life of the car. (or high 200 thousands).

I was a little worried about doing the plug job myself, but its really quite easy. Just need to have a deep 10mm socket. (Luckily my neighbor owns his own tool shop) so he had what I needed.

 

[enne]

I have NEVER used a torque wrench for spark plugs on any car, motorcycle, or truck that I have owned. I have never had a problem. I never will.

Dad has a small Snap-On torque wrench that's made for little stuff like plugs. Considering the old plugs we took out had well over 100k and at least one was only finger tight, one was way over-torqued and another wasn't tight enough to produce spark, I use a torque wrench when I can... Just my feeling about it, much to my dad or other mechanics' chagrin. It's more an OCD thing that I want everything to spec.

But, I realize not everyone has the room for/reason to justify spending money on a tiny torque wrench, when they pretty much know by feel how much torque it needs.

I just went with NGK OEM replacements. If you’re only going to change it every 100k then just put in what works...at least that’s my thinking

I only use NGK on the Honda. They're not expensive and they're OEM replacement like you said. I personally wouldn't leave them in for 100k, but I wouldn't necessarily be worried about them not lasting that long.

 

[Drew03Accord]

Considering the old plugs we took out had well over 100k and at least one was only finger tight, one was way over-torqued and another wasn't tight enough to produce spark

Well, it's a good idea to check the plugs at periods through the life cycle, to make sure none have loosened. That's especially important for the V6 guys. I torque by feel, but I make sure they are in there good and tight...enough. Trust me... I'm very wary of aluminum heads and one mistake with a torque wrench can leave you in a world of hurt.

 

[Drew03Accord]

Gaps were all within specs. I did measure them. (think its .45, or .44) If you search my posts you can see the photo of what I took out and for the age and mileage, I feel these plugs held up VERY well which is why when it was time to replace, I put in exactly what I took out. Figure im good now for the rest of the life of the car. (or high 200 thousands).

I was a little worried about doing the plug job myself, but its really quite easy. Just need to have a deep 10mm socket.

Not sure what you used a 10mm deep throat on, but it wasn't the plugs (5/8).

You could probably have cleaned and reused. Interesting, what NGK has to say about reusing plugs. The "sharp edges" theory sounds like a weak attempt to keep you from hurting their bottom line. I'd have thought they'd come up with something a bit more compelling. Makes me think reusing is perfectly acceptable. Hmm...the cheap bastard in me just perked up. I know they're cheap enough, but why waste good beer money? :devil


https://www.ngk.com/learning-center/article/119/can-old-spark-plugs-be-cleaned

Learning Center
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Can Old Spark Plugs be Cleaned?

November 8, 2011
Technically, yes, you can clean spark plugs, however, in most cases it's not worth it. We do not recommend it for a number of reasons.

Ultimately, you won't get the same performance from a cleaned plug as from a new plug. Electricity discharges best from sharp edges. A used plug will have worn edges, and cleaning may contribute to the wearing.

If you insist on trying to clean anyways, the cleaning procedure below was supplied to us by an old motorhead:

Brush off the plug and firing tip with a clean rag.
Spray the firing end with a quick-dry cleaner such as fuel injector cleaner or brake cleaner. Let sit 10 minutes.
Use a wire brush to clean off any deposits that have loosened.
Blow off the plug and firing end with an air compressor or can of compressed.
Re-Gap to your vehicles specifications.
If the plug has a Flat seat, remember to use a fresh gasket, or adjust the installation torque accordingly.
NOTE: Insufficient cleaning of a spark plug may lead to its failure in a very short period of time. Clean the spark plug thoroughly to avoid problems later. Remember, if a plug is fouling, its usually a result of engine side factors or incorrect Heat Range selection. If, after cleaning, a plug shows unusual signs of wear or doesn't come clean, its time to replace it.

 

[Furple]

Not sure why people try to squeeze out a few $ on something that lasts 100k/10 years EASY, makes no sense to me but I guess I'm not living $ to $... ¯\_(ツ)_/¯

In fact I'd rather leave in 150k iridium plugs than put in crap $2 autolite plugs if I'm honest

 

[scar_cle]

Not sure what you used a 10mm deep throat on, but it wasn't the plugs (5/8).

You could probably have cleaned and reused. Interesting, what NGK has to say about reusing plugs. The "sharp edges" theory sounds like a weak attempt to keep you from hurting their bottom line. I'd have thought they'd come up with something a bit more compelling. Makes me think reusing is perfectly acceptable. Hmm...the cheap bastard in me just perked up. I know they're cheap enough, but why waste good beer money? :devil


https://www.ngk.com/learning-center/article/119/can-old-spark-plugs-be-cleaned

Learning Center
Share |
Can Old Spark Plugs be Cleaned?

November 8, 2011
Technically, yes, you can clean spark plugs, however, in most cases it's not worth it. We do not recommend it for a number of reasons.

Ultimately, you won't get the same performance from a cleaned plug as from a new plug. Electricity discharges best from sharp edges. A used plug will have worn edges, and cleaning may contribute to the wearing.

If you insist on trying to clean anyways, the cleaning procedure below was supplied to us by an old motorhead:

Brush off the plug and firing tip with a clean rag.
Spray the firing end with a quick-dry cleaner such as fuel injector cleaner or brake cleaner. Let sit 10 minutes.
Use a wire brush to clean off any deposits that have loosened.
Blow off the plug and firing end with an air compressor or can of compressed.
Re-Gap to your vehicles specifications.
If the plug has a Flat seat, remember to use a fresh gasket, or adjust the installation torque accordingly.
NOTE: Insufficient cleaning of a spark plug may lead to its failure in a very short period of time. Clean the spark plug thoroughly to avoid problems later. Remember, if a plug is fouling, its usually a result of engine side factors or incorrect Heat Range selection. If, after cleaning, a plug shows unusual signs of wear or doesn't come clean, its time to replace it.

The deep 10mm socket is for the black pastic cover you take off. 2 of the 4 bolts stick out. (at least its this way on the i4, not sure about the V6) For the actual spark plug I bought a 5/8 spark plug socket. The one I had was from my fathers collection from the 70's and didnt fit.....

Also I would never get autolite plugs. Thanks to this site I know not to go that route.

 

[cyclops2]

I can not tell the difference between OEM.

And the new standard Champions in her now. Same power & response & mileage.

 

[pepin]

Little late to this.... I had my oem spark plugs until 154,xxx and the spark plug in cylinder one just BLEW UP . Thanks everyone for advice.