Spark Plug Burn image

http://img217.imageshack.us/img217/7118/znd1.th.jpg (http://img217.imageshack.us/i/znd1.jpg/)

Can anybody pls inspect the burn image of this spark plug?

It have white stuff up of the spark plug and burneds under the regular nipple(didnt find the right word sorry)

http://img220.imageshack.us/img220/3773/sd531740.th.jpg (http://img220.imageshack.us/i/sd531740.jpg/)

http://img219.imageshack.us/img219/4299/sd531742.th.jpg (http://img219.imageshack.us/i/sd531742.jpg/)

Isn't that just the normal white insulator color showing through the combustion deposits?

How old is the plug? Just one like that, or all the same?

I don't see anything alarming there. It doesn't look like coolant deposit, if that's what you were worried about.

Maybe looks like recent heavy fuel additive use the deposits from which have not fully burned away yet?

Here's a typical, healthy normal plug near the end of service life:

http://www.buckeye-illinois.com/images/Plgnorm1_small.jpg

Aside from the lack of the dark band yours has around the firing tip, looks pretty much the same. That's why I say looks like you could have been burning something recently that left that dark deposit...

thx for reply.

I didnt use any additive.
These are Platinum NGK TR55GP and 2 years old.
All 6 spark plugs looks like these.
I mean these area under the elektrode.

http://img81.imageshack.us/img81/3773/sd531740.th.jpg (http://img81.imageshack.us/i/sd531740.jpg/)