Iridium Delco plug problem

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Jul 21, 2007 | 08:17 PM

fullcircle

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Iridium Delco plug problem

I installed Scorpion 1.8 roller rockers and valve springs on my 99 WS6. At the same time i wanted to change the plugs. I ordered a set of Delco Iridium plugs from the dealer by telling them what car I had. I was surprised that the plugs in my car which have never been changed were factory NGK Iridium plugs. When the Delco Iridium plugs showed up they were gapped at .040. Now the owners manual says to gap them at .060. When I gapped the plug the electrode arm was bent back so far it didnt have a good spark path anymore. What gives? I sent them back. Are the NGK Iridium plugs pre gapped any bigger?

Jul 21, 2007 | 08:42 PM

sroach20

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From: houston, Texas

it said .060 from the factory, they changed it cause they found out it did better at .040. never gap a platinum plug, ever. they are preset and you can damage them easily by trying to gap.

Jul 21, 2007 | 11:52 PM

hammerhead

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From: CT

I didn't think GM used NGK from the factory. Are you the original owner?
I just replaced the OEM ACDs at about 70K with ACD iridiums and they were pregapped. The old OEM ones were still pretty clean.

Jul 22, 2007 | 12:20 AM

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I bought my car from the original owner and it had 4500 miles. Its a 30 th anniversary T/A. He never registered the car. So I am pretty sure the plugs werent changed. My thought is that maybe the WS6 cars had NGK plugs?