Iridium plug replacements?
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From: San Francisco CA
Iridium plug replacements?
I've got a 2000 c5 with 31k mi. Decided to replace plugs and wires. 1st time in 18 years as far as I know.
Little confused.
Got the AC Delco iridium plugs (# 41-110) which I thought were supposed to be gapped at .40 in from factory, but they seem to be gapped a little less than that. On the side of the plug box from AC Delco it's says to "SET GAP PER VEHICLE SPECIFICATION" which the manual says the gap for the original platinum plug (#41-952) is .60 in. ??? Also told NOT to use antisieze on them.
So anyone know the correct gap for the iridiums???
Also used the silicone grease (dielectric) that came with the wires (GM GMPP red performance 12495519) on the interior of rubber boots but understand you are not supposed to put the grease on metal connections as it is an "Insulator". Wanted to put something on metal plug connector that attaches to top of plug to help prevent corrosion Little WD40 maybe?
Any thoughts or experience with it would be much appreciated.
Thanks!
Little confused.
Got the AC Delco iridium plugs (# 41-110) which I thought were supposed to be gapped at .40 in from factory, but they seem to be gapped a little less than that. On the side of the plug box from AC Delco it's says to "SET GAP PER VEHICLE SPECIFICATION" which the manual says the gap for the original platinum plug (#41-952) is .60 in. ??? Also told NOT to use antisieze on them.
So anyone know the correct gap for the iridiums???
Also used the silicone grease (dielectric) that came with the wires (GM GMPP red performance 12495519) on the interior of rubber boots but understand you are not supposed to put the grease on metal connections as it is an "Insulator". Wanted to put something on metal plug connector that attaches to top of plug to help prevent corrosion Little WD40 maybe?
Any thoughts or experience with it would be much appreciated.
Thanks!
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41-110 is the correct AC Delco plug. Gap varies by year. IIRC the gap for 1997-2000 is 0.060” and for 2001-2004 is 0.040”. Torque them to 11 ft/lbs. The issue with anti-seize is the concern it could affect the torque. However, a common anti-seize, Permatex/Loctite, says in their instructions to use it and then torque to manufacturers specs. I typically use NGK and they have a torque range of 7-14 ft/lbs, so don’t believe the anti-seize is going to throw it off more than that range. The problem with dielectric grease on the coil end of the plug end is that it can cause misfires. I would think WD40 would have the same potential misfire effect.
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41-110 is the correct AC Delco plug. Gap varies by year. IIRC the gap for 1997-2000 is 0.060” and for 2001-2004 is 0.040”. Torque them to 11 ft/lbs. The issue with anti-seize is the concern it could affect the torque. However, a common anti-seize, Permatex/Loctite, says in their instructions to use it and then torque to manufacturers specs. I typically use NGK and they have a torque range of 7-14 ft/lbs, so don’t believe the anti-seize is going to throw it off more than that range. The problem with dielectric grease on the coil end of the plug end is that it can cause misfires. I would think WD40 would have the same potential misfire effect.
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I can certainly see how getting an excessive amount inside the boot could lead to problems however.
Good luck... GUSTO
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From: Lake Charles, LA
It seems you already have your answer, but I'll back it up again for some extra assurance. Yes, the 41-110 spark plugs are correct. The gap should be .040, not .060. Remember, these cars did not originally come with iridium plugs. The older plugs were platinum, and due to the change from platinum to iridium, the gap spec changed as well. If you ever run the platinum plugs again (if you can even find them anymore) then you would run the .060 gap.
So, just to clarify, if you've purchased the AC Delco Iridium spark plugs (41-110) then the gap should be set at .040 for your car.
As far as putting WD40 on anything regarding the plugs or boots, I personally wouldn't do it. However, I don't really think it would cause any major issues. I just don't think it would help any either.
So, just to clarify, if you've purchased the AC Delco Iridium spark plugs (41-110) then the gap should be set at .040 for your car.
As far as putting WD40 on anything regarding the plugs or boots, I personally wouldn't do it. However, I don't really think it would cause any major issues. I just don't think it would help any either.
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It seems you already have your answer, but I'll back it up again for some extra assurance. Yes, the 41-110 spark plugs are correct. The gap should be .040, not .060. Remember, these cars did not originally come with iridium plugs. The older plugs were platinum, and due to the change from platinum to iridium, the gap spec changed as well. If you ever run the platinum plugs again (if you can even find them anymore) then you would run the .060 gap.
So, just to clarify, if you've purchased the AC Delco Iridium spark plugs (41-110) then the gap should be set at .040 for your car.
As far as putting WD40 on anything regarding the plugs or boots, I personally wouldn't do it. However, I don't really think it would cause any major issues. I just don't think it would help any either.
So, just to clarify, if you've purchased the AC Delco Iridium spark plugs (41-110) then the gap should be set at .040 for your car.
As far as putting WD40 on anything regarding the plugs or boots, I personally wouldn't do it. However, I don't really think it would cause any major issues. I just don't think it would help any either.
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Joined: Oct 2016
Posts: 95
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From: San Francisco CA
It seems you already have your answer, but I'll back it up again for some extra assurance. Yes, the 41-110 spark plugs are correct. The gap should be .040, not .060. Remember, these cars did not originally come with iridium plugs. The older plugs were platinum, and due to the change from platinum to iridium, the gap spec changed as well. If you ever run the platinum plugs again (if you can even find them anymore) then you would run the .060 gap.
So, just to clarify, if you've purchased the AC Delco Iridium spark plugs (41-110) then the gap should be set at .040 for your car.
As far as putting WD40 on anything regarding the plugs or boots, I personally wouldn't do it. However, I don't really think it would cause any major issues. I just don't think it would help any either.
So, just to clarify, if you've purchased the AC Delco Iridium spark plugs (41-110) then the gap should be set at .040 for your car.
As far as putting WD40 on anything regarding the plugs or boots, I personally wouldn't do it. However, I don't really think it would cause any major issues. I just don't think it would help any either.
Thanks.
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From: Guinness Its whats for B'fast JAWGA
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If I am going 18 years between plug changes I would put a touch of anti seize on the plug. If you have wrenched on these motors it isn't uncommon to have to chase threads. I'll take the preventative maintenance.
Agreed I'd use the newer revised gap.
Agreed I'd use the newer revised gap.
Last edited by 93Polo; Sep 28, 2018 at 02:30 PM.
Burning Brakes
Joined: Aug 2017
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From: Newark Delaware
Not to swerve out of lane here, but I am currently fighting with AC-Delco after purchasing 8 iridium plugs for my C5. I sent the rebate form in expecting to get $24 bucks. AC-D sent me a check for 3 dollars. I have sent them two emails that has so far gone unanswered. Buyer beware when it comes to their rebate program.
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From: Michigan
I put a set of the 41-110 in last night, I used a light coat of hi-temp copper anti-seeze on the threads and die-electric grease on both ends of the new wires (as I do with every car I own)
I set the gap @ .040
I set the gap @ .040
Last edited by monteholic; Sep 28, 2018 at 02:37 PM.
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From: San Francisco CA
Thanks.
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I torqued them by hand until good and snug, been putting plugs in alum heads for over 20 years with no issues from my method, some people just get way to OCD about things, and to be honest...I bet they are at least 20ft lbs and I'm not the least bit concerned
I had to open them up to get the .040, ran perfect this morning, idled smoother, the old plugs were well over .060 gap and had 84K on them
I had to open them up to get the .040, ran perfect this morning, idled smoother, the old plugs were well over .060 gap and had 84K on them
Last edited by monteholic; Sep 28, 2018 at 02:59 PM.
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From: San Francisco CA
Thanks! any problems using the .040 gap setting? Mine are off from that on new plugs in box. May take minor adjustment. Did you torque to 11lbs? I too have alway used just a little anti-seize on plugs and plan on going that route even though ACDelco says not to. Hope to be able to get torque wrench on all of them but doubtful but don't plan on going all gorilla on them after getting feel for the ones I can torque.
Thanks.
Thanks.
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From: San Francisco CA
I torqued them by hand until good and snug, been putting plugs in alum heads for over 20 years with no issues from my method, some people just get way to OCD about things, and to be honest...I bet they are at least 20ft lbs and I'm not the least bit concerned
I had to open them up to get the .040, ran perfect this morning, idled smoother, the old plugs were well over .060 gap and had 84K on them
I had to open them up to get the .040, ran perfect this morning, idled smoother, the old plugs were well over .060 gap and had 84K on them
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Joined: Sep 2018
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From: Lake Charles, LA
Thanks for the assurance. Frustrating getting conflicting info on gap from several source. The AC Delco plug box says "set gap per vehicle specification" maybe thats on all of them regardless. which is .060. So that has changed to ,040 because of switch to Iridium? My understanding is that the 1997 to 2000 LSI engines are 345 hp and the 2001 to 2004 have 350 hp. Make any difference for recommended gap setting with the iridiums our ,040 for all c5's?
Thanks.
Thanks.
My buddy has a 1998 with the 41-110 plugs set at .040 and has no issues, runs much better and no more misfiring he says. I have an 2001 and actually plan on putting the exact same plugs with the same .040 gap in my car today.
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From: San Francisco CA
The power and torque rating changed in 01 as "pup cats" were added to all c5's, which restricted exhaust flow and reduced power. In order to make up for that, all 2001 and up got the LS6 intake manifold, a slightly better airbox, and a slightly higher lift cam. That is why they are rated for 5hp more. But no, that doesn't matter when it comes to the plugs. All C5's use the same ones, including the Z06 with the LS6 engine. The f-bodys with the LS1 use the same ones too.
My buddy has a 1998 with the 41-110 plugs set at .040 and has no issues, runs much better and no more misfiring he says. I have an 2001 and actually plan on putting the exact same plugs with the same .040 gap in my car today.
My buddy has a 1998 with the 41-110 plugs set at .040 and has no issues, runs much better and no more misfiring he says. I have an 2001 and actually plan on putting the exact same plugs with the same .040 gap in my car today.
Good luck with your plug change out.
Do you torque plugs? if so how much 11lbs ?
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From: Lake Charles, LA
Thanks, and yes, I torqued them using my short 1/4in drive torque wrench to 132 inch pounds, which is in fact the same as 11 ft pounds. If you don't have a torque wrench that goes that low I wouldn't worry about it. Just make sure they are all fairly snug and don't go crazy with them.
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Picked up a small pack of anti-sieze and will put a tiny film of on threads.
So looks like the plan (after days of trying to figure it out) is:
Gap em to .040
Slight film of antiseize on plug threads.
Torque to 11lbs or finger tight and 1/16th in turn on wrench.
Hope the change out doesn't take as long as figuring out best way to do what I thought was going to be straight forward and simple process. ;-)
Thanks to all for input and help.
Love this site!
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From: San Francisco CA
Thanks, and yes, I torqued them using my short 1/4in drive torque wrench to 132 inch pounds, which is in fact the same as 11 ft pounds. If you don't have a torque wrench that goes that low I wouldn't worry about it. Just make sure they are all fairly snug and don't go crazy with them.
Done over thinkin it all. But better safe than sorry though. Don't want to blow it.
Thanks again.