My car was purchased used with about 60k miles on it, so I've been going through it and doing all the maintenance that I'm capable of, which is pretty much everything routine.

As part of my efforts, the plugs of course got changed. The plugs I pulled were the NGK 11S's, which are what I put back in the car. I know what a good spark plug should look like, but these are a bit white-ish, which makes me think there might be something bad going on. Take a look and let me know what you think. Hopefully the color rendition in the scan is accurate enough.

EDIT: Also, for more info., I checked the gaps on these, and they were all over spec, at about .045mm, as opposed to the .042 gap I used for the new plugs (which is within the spec of .039-.043)

 

Looks like your running lean. The person before you might have had a vfac and a cai. I've seen the burn marks on many, many s2000 plugs so thats not much of a worry. Your fuel filter might be a slight bit clogged or your injectors might be semi clogged also. But the plugs look like your running lean. The wider gap could also be making it a little white. Either you are have a fuel delivery problem or the person who owned the car before you had a vfac a cia and fat gapped plugs. I've had that combo and my plugs where white but not as white. Run the new plugs for a few thousand miles see what ya get with them properly gapped and without all the mods that could have been on the car. you'll be able to read the new plugs after a few thousand miles just fine. It they are still white ya have a fuel delivery problem.

If the owner is going to the extreme to gap the plugs on the high side to squeak some more power there is a good chance he had a cai and or a vfac on the car at one time.

 

There was never a CAI or a VAFC on the car. It was owned by a woman I knew, and she wouldn't have the slightest idea what either of those things were

Since the fuel filter is inside the gas tank, I'm not even gonna go there. I'm running some Techron through the tank however, to see if that smooths things out a bit. Beyond that, I'll do what you mention and see what the plugs look like in a few thousand.

 

NGK has some excellent info on spark plugs on their web site, and they have a page to explain how to read plugs here . Their site was so informative I copied it to keep on my computer in case it goes away on the web.

Their tech guys will also reply to questions. I asked for recommendations for a colder plug for FI applications and here's their response:

You can use the BKR8EIX stock number 2668 or BKR9EIX stock number 2669. Note the spark plug that comes in your vehicle is the only recommended spark plug. It has a special gasket to prevent the spark plug from backing out of the cylinder head. You will need to check the BKR series every once and a while to ensure they aren't backing out.

This is a platinum plug too, so I am going to give them a try.

I though it pretty funny he mentioned the "special gasket". Obviously it's not special enough considering the number of people with loose plugs and the subsequent TSB.

And NGK says 18ft-lbs on an aluminum head.

 

The more I look at NGK's stuff, the more my plugs look very close to normal. Perhaps a bit more white than grey, but certainly not that far off.

Like I said though, I put back in the 11S's, and torqued to 18ft/lbs and used a .042mm gap. Perhaps I should have closed the gap a bit? The plugs were shipped with the .042 gap though, and since it was within spec, I just left them alone.

 

They look pretty normal to me. The gap will always open over time.. go with the recommended gap for that plug. A wider gap offers a bigger spark but platinum plugs don't fire as easily as iridium or copper which will spark consistently over slightly more distance.

 

Those plugs look great! I don't know what Italianbucwheat is talking about. Being a former owner of a turboed car I have seen lean plugs before. They look nothing like that.

 

I agree with the concensus; those plugs look about right to me with the exception of gap.

 

Those plugs are running on the lean side. Like it or not. Its not drastically lean but the optimum plug color is not white! The electrode in plug number one is slightly worn. The engine runs rich from the factory
those plugs are way to white for a completly stock s2000! Thats what I am talking about gagola1.

Is it a big problem no probably not but remeber one thing when you pulled the plugs heffergm you thought they where a little white did you not. So much you posted a question. You also state that the plugs are more white then grey. Therefore you are running slightly lean. Your running lean for a reason
I have never seen plugs that white from a completly stock s2000!

 

http://www.theultralightplace.com/sparkplugs.htm