Read my spark plugs?

[Gabe9195]

I changed the spark plugs in my wife's '08 Shelby a couple days ago, NGK TR6's that have been in for about 7-10k miles.
The gaps were all over the place (started at .030 when installed about 1.5-2 yrs ago), and 2 of them look light in color.
Car has 67k miles on it, has had a '13 TVS pushing about 17 psi for about 1.5-2 years, put down 656/661 on a Dynojet, and it runs great.
Thoughts?

 

[nxhappy]

looks pretty normal. what you look at is the center electrode. It should be a nice tan color like yours. Bad news is when you see shiny silver flakes.

 

[Gabe9195]

Thanks for your reply.
I had a friend that usually really knows his stuff tell me (about the second one on the passenger side, cylinder 2 I think? ) that "Usually when the insulator is polar white like that it's due to steam. Water leaking into the cylinder."
Which obviously worried us, so I wanted more eyes looking at them.
Car runs great, is not losing any coolant.

 

[Catmonkey]

If you had coolant leaking into the cylinders, you'd have evidence of coolant in the oil. Unless your oil looks like a chocolate milk shake, you're probably fine. You need to consider a colder plug than the TR-6 at your boost level anyway.

There's a lot more to reading plugs than just looking at the tips, and you need more detail than what's available in the pic. But, they look to be in the right range as far as color. Electrodes get thinner over time which will account for the larger gaps. You'll notice the center electrodes will look a little less sharp than a new plug. That's norrnal.

 

[fullboogie]

You need to look at the porcelain deep down in the plug for a color reading, not at the tip near the center electrode. EFI cars don't color the tip of the porcelain like the carb cars tended to do.

 

[Gabe9195]

Thanks guys. I went back and snapped a few more detailed pictures, in case any of you don't mind studying them a little closer
Please let me know what you think.

 

[Catmonkey]

Hard to say without looking at them first hand with a magnifying glass, but those little specs that show up could be evidence of detonation.

 

[Gabe9195]

Hard to say without looking at them first hand with a magnifying glass, but those little specs that show up could be evidence of detonation.

Occasionally if in 6th gear, going 60+ and just pressing down on the gas pedal somewhat to gain 10-15mph, I'm pretty sure I've heard some pinging. That could've caused those specks, right?
We try not to do that anymore and just downshift to 5th

 

[Catmonkey]

It's really hard to say. Colder plugs may help, but bad gas can be anywhere at anytime. Without knock sensors, you might consider a little more conservative tune. I think I'd take note of which cylinders had the most specs and check them after a few hundred miles on a new set of plugs and see what they look like. Some detonation is inevitable. I've seen way worse. If you're going to run TR-6s, change them more frequently than 7 - 10k miles.

 

[fullboogie]

And let me add that you still can't see the portion of the porcelain that needs to be seen. You'll need a light and magnifying glass, and you'll be looking at the bottom 1/2" of the porcelain nearest the base.

 

[1st usa car]

you probably should have colder plugs and a smaller gap - like .28

 

[Gabe9195]

Well, a colder plug would be something like the NGK TR7IX, right? Which is an Iridium plug.
I run those in my blown '13 GT and I noticed a smoother idle and an overall smoother-running engine after putting them in and removing the zero-heat-range Motorcraft plugs that I had in there.

 

[Catmonkey]

Well, a colder plug would be something like the NGK TR7IX, right?

Yes, one range colder.

 

[GT Premi]

Occasionally if in 6th gear, going 60+ and just pressing down on the gas pedal somewhat to gain 10-15mph, I'm pretty sure I've heard some pinging. That could've caused those specks, right?
We try not to do that anymore and just downshift to 5th

Sixth gear in the GT500 is not for accelerating, especially not from 60MPH.

 

[Gabe9195]

Sixth gear in the GT500 is not for accelerating, especially not from 60MPH.

Yeah, it's an overdrive gear, but it accelerates very well in 6th, even from only 60-65. Gotta love that torque, especially with the 3.73 gears

 

[Joewee500]

I don't use 6th unless going over 70 and it's to cruise only. I try to never lug the engine. Rpm stays over 2k most of the time.


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[rotor_powerd]

Yeah, it's an overdrive gear, but it accelerates very well in 6th, even from only 60-65. Gotta love that torque, especially with the 3.73 gears

6th is a double overdrive. Cracking the throttle open at low RPM with that much load sends cylinder pressure through the roof. That’s when detonation happens, especially with a hot plug.

Need to see the strap to tell how the timing is.

 

[VNMOUS1]

Yeah, it's an overdrive gear, but it accelerates very well in 6th, even from only 60-65. Gotta love that torque, especially with the 3.73 gears

B A D idea.

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