Autolite Spark Plugs
 

Thoughts/experience Autolite iridium enhanced spark plugs:

http://www.autolitecatalog.com/PartD...?b=A&pn=XP5263

Please don't unless you're looking forward to staring at a CEL eventually.

The Ecotec engines were designed and tuned around the Delco Iridium spark plugs, and many members have found out the hard way that straying from the Delco plugs is asking for trouble.

Think misfires and rough running for starters.

Thanks for the advice.

Do you have an explanation?

While I've never seen a technical paper or write up as to why Ecotec engines perform poorly on non-Delco plugs, they just do.

If you want my best guess, I'd say the ignition system parameters are maximized around the electrical characteristcs of the Delco Iridium plugs.

It's the same way with other makes, Honda cars like NGK plugs, BMW cars work best with Bosch plugs, and Chrysler's prefer Champions.

I doubt differences in electrical characteristics account for this. More likely effective heat range, reach/exact position in combustion chamber, various dimensions. That kind of thing.

Have you done a side by side comparison?

Anyway, I'm going Delco.

Valid points, and valid possibilities, and no I've never done a sde by side comparison with "Brand X" plugs.

When these engines are running "right" they are so very nice, but when they're running "wrong", they are no fun to deal with.

My curiosity is almost always quelled by the realization that experimenting can backfire on you, and usually when negative results are least desired.

One other note, the Delco's are pre-gapped at the factory then shipped with plastic sleeves over the electrode end to protect it. Examine them visually for damage or bent ground electrodes, but do not attempt to re-gap them. Just return any damaged plugs for replacement, the center electrode wont stand any gapping attempts without suffering damage.

do it right...get get ac delcos and avoid any problems....

oh...and use some di-electric grease inside the plug/coil boots..:thumb:

Definitely.

On spark plug terminals as well.

I can easily imagine a dimensional difference between brands leading to something like threads exposed inside combustion chamber - possibly causing pre-ignition or similar. If possible, I'll do a side by side comparison.

41-981 is what was in mine (2006 2.2 ), all I could find, and what was recommended was, 41-105 Delco Iridium, seems to be running ok. I did have to regap a couple, was very careful with tip, used the round gauge very carefully.

Bill