For awhile now I've been saving one or two sets of my old plugs to check wear and deposits over time.

This latest time I did a plug change, I noticed on my leading plugs, both rotors have this tan colored deposit on them. Not thick or anything - I could barely scrape enough off the whole plug to accumulate anything on my fingernail.

I'm puzzled as to what this is? Coolant? Running to hot? Detonation? What?

Anyone have some insight to this? I'd be most appreciative.

Thanx

JB

 

Top plugs are the trailing, bottom leading. Just remember T for top, T for trailing.

Sounds like normal wear to me. Tan is good.

Look on the inside back cover (or last page, or inside front, cant recall) of ANY Haynes manual. It has a whole page with different pictures of plugs and their prognosis.

Coolant leaves a scent on the plugs, like gas. If your running too hot they will be worn faster than they should be, like rounded edges.

And detonation looks like the plug was chewed up and spit out, literally. Massive deformation.

 

"Tan" is the typical color of normal spark plugs.&nbsp The tan color actually comes from gasoline additives.


-Ted

 

Right on! Holy crap, I think I finally have it tuned right, then!

Load off my mind - thanks guys!

Oh, and w/b, Ted... next time you go to HI, I expect an invite!

JB