Spark Plug Tip Diagnosis

Spark Plug Tip Diagnosis PDF (http://www.autolite.com/pdf/PlugTips.pdf)

(Courtesy of Autolite.com)

Nice straight forward diagnostic tip. Everyone should have this. It is all to often that we predict the worst before we start with the basics!

I prefer the one by NGK.

NGK How Do I Read a Spark Plug (http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp?mode=nml)

What is interesting is I've never had a plug look like what is in Photo 1 of the Autolite reference including running VP Racing unleaded race fuel. Normally the ceramic insulator is a lot lighter and never a tan color as shown. More towards grey/white.

http://i5.photobucket.com/albums/y186/lizzywiz/ac41921_3.jpg

Thanks, I agree, the NGK site does a great job showing different scenerio's.

Great information to share!

Quite interesting Bob,

One question, did you open that gap up on your plug? Or is that how it looked when it came out?

Should I gap my TR6IX's to .060" or .055"?

Probably just an optical illusion Tim. The gap was right on at .060". These were the Delco OE double platinums (41-921) that I replaced on my Regal GS. You can see the tit on the negative electrode which has to be used or in the equation to gap the plugs properly at least on the Delco double platinums. I now use NGK TR55IX Iridium on it and the negative electrode is fully adjustable and without the tit.

Gap the TR6IX to .055" since you have a SC pulley mod.

Sounds Good! Thanks!