AC Delco Irridium Plugs
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Joined: May 2008
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From: Chicago IL
AC Delco Irridium Plugs
I got these plugs a few months ago and just put them in and now waiting for the wire set to arrive. I noticed the plugs were alot more than the .040 gap that they suppose to have. So made the gap at .040, but now I hear your not suppose to gap them, they're gapped when manufactured.
So did I messed up these plugs already and need to get new ones? Worst scenario I need to get new ones?
So did I messed up these plugs already and need to get new ones? Worst scenario I need to get new ones?
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
I encountered the same thing recently when I switched out mine & a friends plugs to the Iridiums.
The printing on the plug boxes, clearly states that the plugs are already
pre gaped and not to gap them.
Well, the one's that I encountered were gaped at different gaps
.
If your very careful when gaping the plugs, you will be just fine.
The very small diameter of the center electrode could be easily be damaged while doing the proper gaping... and also if not using the proper fitting tool.
The printing on the plug boxes, clearly states that the plugs are already
pre gaped and not to gap them.
Well, the one's that I encountered were gaped at different gaps
.If your very careful when gaping the plugs, you will be just fine.
The very small diameter of the center electrode could be easily be damaged while doing the proper gaping... and also if not using the proper fitting tool.
Safety Car
Joined: Apr 2007
Posts: 3,640
Likes: 84
From: . New York
I encountered the same thing recently when I switched out mine & a friends plugs to the Iridiums.
The printing on the plug boxes, clearly states that the plugs are already
pre gaped and not to gap them.
Well, the one's that I encountered were gaped at different gaps.
If your very careful when gaping the plugs, you will be just fine.
The very small diameter of the center electrode could be easily be damaged while doing the proper gaping... and also if not using the proper fitting tool.
The printing on the plug boxes, clearly states that the plugs are already
pre gaped and not to gap them.
Well, the one's that I encountered were gaped at different gaps
.If your very careful when gaping the plugs, you will be just fine.
The very small diameter of the center electrode could be easily be damaged while doing the proper gaping... and also if not using the proper fitting tool.
thats what I found when I did mine a good while ago at a friends shop. Perplexing. I think we regapped a few, at any rate no problems with them 
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Advanced
Joined: May 2008
Posts: 87
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From: Chicago IL
I used a regular gaping tool and was sort of careful when adjusting the gap. Hopefully everything is ok at start up.
At least I know this for the next time not to gap them.
Will keep you posted.
At least I know this for the next time not to gap them.
Will keep you posted.
Instructor
Joined: Aug 2012
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Safety Car
Joined: Apr 2007
Posts: 3,640
Likes: 84
From: . New York
Odd, Ive never heard of touching the electrode to gap a plug. Even with the Iridium ones (if you choose to) you are usually only bending the strap up or down.
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Le Mans Master
Joined: Sep 2007
Posts: 7,604
Likes: 8
From: Belleville Il
I to re-gapped mine as mine also had a variety of gap readings. I used the little gapping tool that fits on the side of the ground strap..gave it small tweaks to bring them in spec and they have been doing fine for over 30,000 miles.
My guess is they don't want folks messing with them as there are a LOT of ham fisted DIY types out there that mess them up and want exchanges or refunds. They figure with the strong modern ignition systems today that they will cover the "close enough" factor. The old plugs I removed had lost several platinum discs of the ground strap,,and they had gaps all over the place,,and if you weren't paying close attention,,you'd think it was running fine,,,till you changed them out. Mine REALLY perked up after the new iridiums!!!
My guess is they don't want folks messing with them as there are a LOT of ham fisted DIY types out there that mess them up and want exchanges or refunds. They figure with the strong modern ignition systems today that they will cover the "close enough" factor. The old plugs I removed had lost several platinum discs of the ground strap,,and they had gaps all over the place,,and if you weren't paying close attention,,you'd think it was running fine,,,till you changed them out. Mine REALLY perked up after the new iridiums!!!
Safety Car
Joined: Dec 2011
Posts: 4,704
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From: Redondo Beach CA
what do I need to know about iridium plugs?
what are the particular concerns about gapping this type of plug? I have never used an iridium plug before.
I have a couple of tools I could use, my main concern is to preserve the finish on the working end.
I also have a question about indexing the plugs. It's probably not going to happen this time, but I just want to check. I assume the open area should face the fuel intake, and want to check my memory.
I once saw a guy set the gap by pounding plugs on a fender. Not my favorite technique but interesting to see how some guys work fast. Closed the gap by tapping the ceramic side, opened by tapping the side. The only positive about this guy was that he didn't scratch up the electrical face. I usually use a plier like tool that squeezes down on the plug, but I am concerned about working without any surface damage since the plugs will probably be in there for over a decade and the sparking areas are very small and delicate. The car will be an antique before the next set.
Thanks in advance.
I have a couple of tools I could use, my main concern is to preserve the finish on the working end.
I also have a question about indexing the plugs. It's probably not going to happen this time, but I just want to check. I assume the open area should face the fuel intake, and want to check my memory.
I once saw a guy set the gap by pounding plugs on a fender. Not my favorite technique but interesting to see how some guys work fast. Closed the gap by tapping the ceramic side, opened by tapping the side. The only positive about this guy was that he didn't scratch up the electrical face. I usually use a plier like tool that squeezes down on the plug, but I am concerned about working without any surface damage since the plugs will probably be in there for over a decade and the sparking areas are very small and delicate. The car will be an antique before the next set.
Thanks in advance.
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Same here. 
The iridium alloy center electrode, in addition to being very thin, is also more brittle than the old conventional design and easily damaged/broken unless care is taken when checking the gap. I use a wire-type gauge to check the gap and use great care when checking, not to mention doing all adjusting by bending on the ground strap only. I have checked/adjusted the gap on iridium plugs several different times with no problems at all.
The easiest tool to use and least likely to cause damage:
K-D 166
or K-D 165
Premium Supporting Vendor
Joined: Nov 2006
Posts: 30,317
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From: Reading PA
The Iridium plugs have a much different gap than the original plugs and I think that was the basis of the question. You are not supposed to re-gap them to the older plug gap, no.
Le Mans Master
Joined: Sep 2007
Posts: 7,604
Likes: 8
From: Belleville Il
When I got mine at a traditional (not a chain store) parts house I had them look up the specs,,and it said ".040,no variation",but the plugs out of the package were all over the place. So I carefully gapped them all to .040.
Instructor
Joined: Aug 2012
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Safety Car
Joined: Dec 2011
Posts: 4,704
Likes: 239
From: Redondo Beach CA
This stuff is new to me. In looking over the Delco plugs, there is no crush washer, a first for me.
Are all modern plugs like this?
I usually use Ngk or champion plugs, depending on the car, and perhaps it was the age of the cars, but the spark plugs always came with a crush washer. If it is just the AC Delco stuff that forgoes the crush washer, I would have picked another brand
Are all modern plugs like this?
I usually use Ngk or champion plugs, depending on the car, and perhaps it was the age of the cars, but the spark plugs always came with a crush washer. If it is just the AC Delco stuff that forgoes the crush washer, I would have picked another brand
Melting Slicks
Joined: Jul 2006
Posts: 2,332
Likes: 31
From: Silver Spring MD
My new Iridium plugs were misgapped
Checked with feeler guage. 4 out of 8 were misgapped. Took a gapping tool and gently regapped the out of spec ones. Apparently the Iridium plating is very thin and if not careful you will scrape it off the electrode.
Having misgapped plugs is much worse. Take your time and make sure they are gapped to spec.
Having misgapped plugs is much worse. Take your time and make sure they are gapped to spec.
Premium Supporting Vendor
Joined: Nov 2006
Posts: 30,317
Likes: 165
From: Reading PA
What I was trying to say that the Iridiums are a different gap than the originals, first. Second, of course if the new plugs are not within the spec of the newer gap, then by all means that certainly needs to be fixed.
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Completely. And I think it goes without saying, as has been pointed out, that any checking and/or re-gapping MUST be done with great care. The "DO NOT RE-GAP" caveat on the boxes is a CYA thing to keep the bean counters happy because far too many people are too ham-fisted when trying to deal with gapping spark plugs. Much of that I think is from the old-school days of standard plug designs. I call it the "Get a Bigger Hammer" school of maintenance. 
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From: Chicago IL
Update: Wires came in and installed them along with finishing other mods that I added. She hesitated for a bit to start but roared up after four tries. She's running smooth and very nice. The LT's, Vararam, ECS pcm and tune up really woke her up. Very satisfied.