DENSO IKH20TT quality question

[inquirer]

I just bought 4 DENSO IKH20TT spark plugs over the Internet.

One of them has a dent in the thread near the bottom (last photo) and its tip about the middle is a little uneven (first photo). (See photos in full size in order to understand what am I talking about by right clicking on them and selecting "View Image").

1. Do these things indicate any problem about the spark plug?
2. Also there are a few left overs from the plastic cover in the thread (tiny plastic pieces). (If you pay attention you can see them in all 4 photos.) Should I remove them before installation. Would they cause any problem if they stay there?

Thanks in advance for your time!

 

[HerrStig]

I stick with NGK.

 

[Falken]

I just pulled out Denso from my Fit, was expecting to see NGK.

They looked very good, no issues.

I changed them with 4 new NGK. As far as I can tell, no difference.

I do trust NGK more.

 

[tomcat27]

If you have a compressor, use an air nozzle to blow the plastic residue off the threads - but if you don't it certainly wont hurt anything. as far as the damaged threads on the last one, the situation is not perfect since theoretically you will cause slight damage to the upper threads on the cylinder when you install the spark plug - although only very slight and its near the top of a very long plug thread.

all that said, install the plugs and don't worry. I've used Denso's on two of my Toyotas.

 

[ARCOgraphite]

When I was doing tunes in the 80s and 90's Nippon Denso was a much better build - on OE and aftermarket plugs. NGK usa made V power were garbage. If you put a NGk wher a denso was in a Subaru it would run like garbage. If you put a NGK wher a Champion was in a Subaru or Hyundai it would run like garbage.

Woth fine wire Ir I imagine the field is a bit leveler.

IOP I was a bit disappointed in the TT, I had to "blueprint" them to get them symmetrical and squared up.

I still have the set, I couldn't get the wires off my Ranger 2.3! And I didn't want to ruin them yanking them off with plug wire pliers as the car was under warranty.

 

[inquirer]

Originally Posted By: tomcat27
If you have a compressor, use an air nozzle to blow the plastic residue off the threads - but if you don't it certainly wont hurt anything. as far as the damaged threads on the last one, the situation is not perfect since theoretically you will cause slight damage to the upper threads on the cylinder when you install the spark plug - although only very slight and its near the top of a very long plug thread.

all that said, install the plugs and don't worry. I've used Denso's on two of my Toyotas.


Are these imperfections (the small dent of the thread and the uneven thickness of the tip in the middle (I was referring to its thickness in the middle, not the top surface of the tip) common variations of the manufacturing process or do they indicate things like a fake spark plug or mishandling during storage, etc.?


Originally Posted By: ARCOgraphite
When I was doing tunes in the 80s and 90's Nippon Denso was a much better build - on OE and aftermarket plugs. NGK usa made V power were garbage. If you put a NGk wher a denso was in a Subaru it would run like garbage. If you put a NGK wher a Champion was in a Subaru or Hyundai it would run like garbage.

Woth fine wire Ir I imagine the field is a bit leveler.

IOP I was a bit disappointed in the TT, I had to "blueprint" them to get them symmetrical and squared up.

I still have the set, I couldn't get the wires off my Ranger 2.3! And I didn't want to ruin them yanking them off with plug wire pliers as the car was under warranty.


Yo had to get them symmetrical and squared up? Where exactly were the problems?
The TT are supposed to be Denso's best spark plugs if I'm not mistaken.

 

[tomcat27]

I just checked the two boxes of Denso's that I have. my vote is just poor quality. none of mine are aligned perfectly; nor are the threads all that great. I'm guessing that they are "good enough" for what they are intended for. Mine are made in Japan.

 

[inquirer]

Mine too are made in Japan. Thanks for the update.
The TT claim that they last for over 100,000 miles. I'll see that in practice.

 

[SHOZ]

70k on my Denso TTs.

 

[Gokhan]

No problem. They aren't meant to be manufactured perfectly. They are just spark plugs -- not rocket science -- and they will do the same thing regardless. With the Iridium TT, you get slightly higher efficiency due to reduced electrode size (less quenching of the initial fireball), without compromising the electrode life.

 

[GMBoy]

Those are excellent plugs and priced right. No issues with the small imperfections you see - you'll see that with any make of plug.

 

[cmhj]

don't let a little "dent" throw ya

 

[inquirer]

@SHOZ
Not bad.

@Gokhan
It isn't rocket science, yes. But with the tip being only 0.4 mm wide it makes me wonder what is the acceptable tolerance of misalignment. Anyway, I installed them today and there is a power gain (better throttle response at least in low RPM) noticeable enough in order to be sure that it isn't just in my head. Of course the comparison is done with the previous worn Bosch FR7SI30, so I don't know how much of this improvement is due to their new condition or because of the superior technology...

@GMBo
Well, that's what I was expecting to hear. When you are purchasing what is considered a top of the line spark plug you expect to perform with in its specs and not having construction issues that would cause underperformance. As long as the small imperfections don't cause any issues, there is no problem though...

@cmhj
Well, no. As I said I installed them and their is an improvement!

 

[ARCOgraphite]

Nippon Denso HOT-U plugs were much better out of the box quality than the TT's. Equally good are bosch std plugs.
Ive opened hundereds and hundreds and HUNDREDS of boxes of plugs whilst performing professional and personal tunes over the years; I had expected American plugs to require blueprinting/adjusting, I did NOT expect to have to do this on a premium Japanese built plug.

I guess we have successfully Westernized the Islanders after all

 

[SHOZ]

Originally Posted By: ARCOgraphite
Nippon Denso HOT-U plugs were much better out of the box quality than the TT's. Equally good are bosch std plugs.
Ive opened hundereds and hundreds and HUNDREDS of boxes of plugs whilst performing professional and personal tunes over the years; I had expected American plugs to require blueprinting/adjusting, I did NOT expect to have to do this on a premium Japanese built plug.

I guess we have successfully Westernized the Islanders after all

Do you expect boxed plugs to be properly gapped for all applications? On my Genesis Coupe the plugs come pre-gapped at .044" out of the box (the Hyundai recommendation). From the factory the plugs are gapped at .028" as installed. I find they run best at .032"

 

[splinter]

NGK for a long and zappy life?

 

[ARCOgraphite]

We had "tricks we did to champs when we went racing, like clipping the gnd electrode and making them side fire. That was back in the drag racing days with sbc bbc and nailhead buick motors.
You want a more consistent running engine on a inherently rough, buzzy 4 banger, try a flush or recessed electrode plug. Many problems are improper igyy time.

 

[Gokhan]

Originally Posted By: SHOZ
Originally Posted By: ARCOgraphite
Nippon Denso HOT-U plugs were much better out of the box quality than the TT's. Equally good are bosch std plugs.
Ive opened hundereds and hundreds and HUNDREDS of boxes of plugs whilst performing professional and personal tunes over the years; I had expected American plugs to require blueprinting/adjusting, I did NOT expect to have to do this on a premium Japanese built plug.

I guess we have successfully Westernized the Islanders after all

Do you expect boxed plugs to be properly gapped for all applications? On my Genesis Coupe the plugs come pre-gapped at .044" out of the box (the Hyundai recommendation). From the factory the plugs are gapped at .028" as installed. I find they run best at .032"

In my experience, with dozens of boxes of them I've bought, Nippondenso standard U-groove plugs don't come with the electrodes perfectly aligned either. However, as I said, this is a nonissue, as it makes no difference in performance.

All Nippondenso spark plugs are factory-gapped to precise specs and you shouldn't try to regap them, which will only make them out-of-spec.

NGK versus Nippondenso? I would go with Nippondenso every time. Nippondenso is the OEM standard these days. NGK used to be the secondary OEM recommendation after Nippomdenso for Toyota but these days only Nippondenso is recommended, as its iridium twin-tip technology is the state of the art in spark performance and longevity.