Originally posted by dbbubba:
I read in another thread that gapping the spark plugs a bit closer will cause them to run cooler. Recall that I have had the problem with a few spark plugs having cracked insulators. Another guy said that the idle would improve if I gapped them at spec or even wider than spec.

While I appreciate both people's opinions I wonder which is the best for my engine at this point. According to the thread that suggested that I gap them closer this advice was given by someone who once worked for Autolite or another major spark plug manufacturer. The suggestion was given as a way to prevent the insulators from cracking since the plugs would run cooler.

I presently have them gapped at .045 instead of .050 and it runs pretty good. The idle is even although I can feel the idle through the steering wheel. I always figured this was due to aged motormounts.

Any suggestions?

DB



.050 is the gap Ford calls for on my Zetec. And while we're talking of plugs, I see that you've had cracked insulators. As you know I've had the same problem. I thought it was just on the Motorcrafts, but I just happened to look at the 2 previous sets of Autolites and two of them in each set had cracked insulators, so it was more than the incorrect plugs, which may have been a big part of it, but now there's a new wrinkle in the equation. But I can not stress enough that there is only one way to crack an insulator on a plug. And that is from spark either leaking out, or spark trying to bust it's way in. My plugs all had big cracks in the ceramic, from the top to the bottom where the plug wrench engages the hex nut. And over time there was a huge carbon mark, from electricity. So if you have not replaced your plug wires yet, and you still have broken insulators reoccurring, it's plug wires, or more specifically plug boots. I really think that my boots were getting old, and removing them to replace the plugs cracked the boots. I have not discerend yet if the cracked boots are letting the spark escaping from the plug and shorting out to the head, or if the spark is coming back in through the head and getting in through the boot back to the plug. I guess after looking at what I wrote the second scenario doesn't sound real plausible, but, who knows ? Just thinking about it it seems logical also that your bad boots/wires could possibly burn your coil pack up ? I think someone told me this a while ago when I was hot on the trail of trying to find out why I was blowing plugs out.

Ken, 99 Silver Frost SE Zetec Atx, polished alloys, Kumho's, Pioneer hi power CD/AM/FM. Factory spoiler (added) Audi side lites, Borla stainless steel muff. Stolen, recovered in pieces. Looking for another Tour, preferably V6, 5 speed.