Spark plug gunk

[joesdc]

Hello Everyone,

I re-placed my spark plugs yesterday and the old ones seemed like they were covered in dirt or sand. I couple of the plugs were wet looking but the others were dry. I have included a picture of the old plugs and one of the plug holes. Not sure if this is normal for plugs that are in need of being re-placed or should I worry that it is a sign of other problems? I am a mechanically inclined person but do not have a lot of experience working on cars. I also was not sure on how the new plugs should be gapped. I bought them from DeLorean Industries and went ahead and gapped them at .035 which seemed to be what the old ones were.

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Thanks,
Joe

[David T]

To "read" spark plugs you look at the part of it actually inside the combustion chamber. The threads don't tell you much except that some oil got into the spark plug well. From what I can see of your plugs they look normal.

[Spittybug]

Agree. Normal.

[David T]

Forgot to mention, the gap is supposed to be .024-.028. Assuming your old plugs were gapped correctly and assuming wear of .001 per 1,000 miles, your old plugs were in about 10,000-15,000 miles. While the plugs are out it is a good opportunity to measure the health of the motor by doing a compression test.

[joesdc]

Thanks for all the great info. I will gap the plugs correctly. Nice to know about the plug wear as well. I will also look into doing a compression test.

Thanks again,
Joe

[DMCMW Dave]

The "sand" is probably solidified anti-seize compound.

[Jonathan]

I would stick the nozzle of a Shop-Vac or regular vacuum cleaner down in those holes and get as much of the gunk out before you put everything back together.

I had similar grit all over mine when I changed them too. Hadn't thought of it as being solidified anti-seize, but I bet that is right. Good call Dave.

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