SG Lou

I was under the impression that the plug was a Iridium 41-110 but I came across this Bulletin, Subject: ACDelco Spark Plugs 41-110 and 41-962 - Application Update


http://acdelcoadvantage.saepio.com/L...13/13D-070.pdf


ALSO...CHECK OUT THE CHART ON PAGE 2

http://acdelcotechconnect.com/pdf/ne...-news-2013.pdf

jose7740

I bought my 98 about three months ago with 132,000 miles and at my first tune up used the 41-962 plugs not knowing about any bulletins from GM and I picked those because they were listed in the auto parts store along with the all other iridium plugs from Delco and everybody else, they were about two dollars cheaper than Delco and they work real good

LoneStarFRC

They both "meet spec". The platinums (962s) are cheaper than the iridiums (110s).

strand rider

I have been wondering about this since SG Lou brought this to light in another post. I know that is not much for me to brag about.

I was wondering what advancement has allowed the double platinum plug to supersede the old plug.

I can understand wanting to bring a price advantage to market, but the good conductive platinum was already replaced by the inferior conductor, iridium , when they bumped the specs in the 20001 engine.

Now it is back, and the engine hasn't changed, so it could be interesting, if your trigger of interest is as low as mine. I am even wondering about the ding dang spark gap, new verses old. Will it stay the same , or will conductivity advancements change the gap. I wonder about that, then wonder why I even bother to spend time considering future spark plug gaps.

So I don't think the advantage of better conductivity is the deal changer here, it could be a new machine has cut costs, both thoughts could no more than be a poor guess, How would I know?

It is just the idea of a new design, or even a new manufacturing process being the driver for this change, I find interesting. I don't think it is the cost of platinum driving change, another guess.

The iridium plug continues in the newer stuff, and still meets specs for all the new applications for the platinum , again reinforcing my thought that conductivity is not the critical concern with the kind of spark available. So what changed about the double platinum plug to now make it able to meet spec?

It gets even worse. My spark plug interest is fueled by the viewing of a collection of old spark plugs in some display somewhere, most dating to the time where the optimal shape of a spark was still open for debate. FRom viewing that assembly, I continue to find out about spark plugs, expanding the time line that is part memory, part imagination, as I contrast the new with the old, and continue adding to the memory of the display with new thoughts. .

I guess I will cruise on over to the AC delco web site , to see if they are bragging about features of the new plug. I don't have a lot of hope of any info on manufacturing advances, or deep cost strategies.

jackthelad

Your comment re viewing old plugs reminds me that many years ago (my grandfather's day), in England if you wanted "quality" plugs you bought Lodge. They were unique in that they had a central anode, but 3 cathodes pointing at it, rather than the typical bent over piece of metal we see today. See: http://vintagegarage.co.uk/vg/vgimag...e/1919%203.jpg

The theory being you got a more distributed spark. I think Lodge may have been OEM for Rolls Royces way back when.

SG Lou

I posed this same question to C4/C5/C6 Specialist Paul Koerner and his reply to me was this: " The story is ACDelco is wrong from a technical aspect.

They are doing it for pricing so that they will sell more plugs at a cheaper cost.

41.110 is the ONLY plug I put in any LS1 LS6 LS2 LS3, applications for LS7 and LS9 are different.

All the best, Paul "

Paul seems to know his stuff so I'll take his word for it !

MAC5

Paul relayed the same info to me a couple of years back when I was changing my 98's plugs.

41-110's gapped at .040

tblu92

I don't think the new plug recommendations have anything to do with the metal used in the plugs----Whether they are plain old copper cores or single platinum or double platinum or single or double irridium---The reason for the change of part numbers is strictly because GM is now recc. a .040 gap rather that a previous .060 gap--- The original part numbers all came pre-gapped at .060---
You can buy NGK plugs gapped at .060 and the part number is a TR55---- But the same exact plug gapped at the new recc gap of .040 is a part # TR5
When it come to Irridium and Platinum plugs they are all pre gapped at .060 --No part number for them pre gapped at .040 That's why they aren't listed or recommended -
GM would prefer you buy pre-gapped plugs However anyone with minimal mechanical knowledge can re-gap any plug part # to the newly recc. .040

Russell Boulding

GM changed its recommended spark gap from .060" to .040". I believe at the time the did not have a proper iridium plug with a preset .040" gap in their line-up for the C5. They are not fond of people gapping iridiums in the field due to possible electrode damage. But, now there is a proper .040" gap iridium available for the C5. The new recommendation is 41-985 and that is what we use here at the shop.

*Edit* Had a car in today for plugs and was out of stock so I went to order more. My local Delco vendor did not have 41-985 so I did a little digging and the 41-110 is the superseded number for the 41-985 according to my Delco rep. This makes more sense as the 100 series number are supposed to be iridiums and the 900 for platinums. The 985 was the only weird iridium with a 900 number. And the 41-110 is a .040" gap plug. I was looking at an outdated TSB #03-06-04-060B when I posted the above information and still had 985's on the shelf from the last stocking order. By looking at the Delco PDF's it says that the changes are geared towards being cost competitive. The cars came with double platinums so they figure no harm in selling double platinums as the "OE" recommended plugs. Previously, we had been running 41-985 for our customers which were coming gapped at .040" and our latest stocking order of 41-110 all came gapped at .040" (at least the eight we checked) and that is what we will continue to run here *Edit*

SG Lou

Here ya go Mac5

http://www.thecorvettemechanic.com/forum/

MAC5

Thanks, I tried my link later in the afternoon and it worked. I may have had internet prob's or his site was down for maintenance. Paul's been an extremely valuable source of information & advice for years on the C5.

strand rider

My plugs were shipped from GM parts house gaped at .04 on the 41.110 part . So, in my instance , the part number does not describe the gap. Two were gapped incorrectly, I assumed from shipping impact, but perhaps they were old stock, with an old gap, I didn't measure, but they were more open.

Corvette_Ed

This is incorrect. The AC Delco 41-110's I bought three years ago all came gapped at .040. I never install a spark plug without checking the gap in it first as it is possible for quality control to miss a plug during manufacture and send one out over- or under-gapped, so I know for certain every one was at the .040 gap.

tblu92

If it's not the GAP then why would the poster say "AC Delco say not to use them ????--\
Either the poster is wrong---\
Or AC Delco is wrong
AC Delco may have changed their settings from the original setting--The poster's information may be old and PRE-Change
C5's came out in 1997--3 years ago was 2011 when you bought your set at .040--- A lot could have happened in 8 years---
I think It could be all about price point and the "corvette tax"
If not that then all we are left to assume is the GAP----

Corvette_Ed

Iridium is more expensive than platinum to obtain and manufacture. It's all about selling a cheaper plug for AC Delco. The OP's info came from what looks to be an announcement put out just last year. They'd just made the switch to the new plug gap when I'd bought mine in 2011.

SG Lou

tblu92......did you not read the 2 attached pdf files? First off, they are both dated May 21,2013 so they are not that old, secondly, It was AC Delco, not me who said don't use them.

ACDelco Spark Plugs 41-110 and 41-962 - Application Update
WD Bulletin 13D-070
ACDelco announces that 2006-and-older, as well as some 2007, spark plug service applications
covered by the iridium spark plug 41-110 have moved to the platinum plug 41-962. 2007-and-newer
applications used iridium plugs in production and service requirements will remain assigned to the
iridium plug, 41-110.

Another thing.....no where in the Bulletin does it mention anything about plug gaps. Someone else brought that topic up...not me.

And last but not least, if you read my other post, 6th one down, it explains how I contacted C4C5 Specialist Paul Koerner and posted HIS reply to this question that I originally started this thread with.