Tune-Up on LS1?

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donnyj08

donnyj08

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Im going to change the plugs on my LS1. Gm has changed the Ac-Delco part numbers for plugs so much since 2000 im not sure which plugs to use. I bought 41-962 platinum plugs, but some are suggesting using Copper NGK TR-55 plugs for the best value/performance. others buy expensive Iridium plugs. The plugs in the car now are Ac delco 41-952 which i don't think exist anymore.

should i switch the the TR55's for 1.99 each and change them every 30k or keep the platinums i have purchased? What do you LS1 guys recommend? the car is bone stock, all the way to the air filter. thanks!

-Donny
 
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Changing the plugs in my Camaro is such a pain, I put long-life plugs in it and change at 90K mile intervals. I have changed plugs twice in the Camaro's life, and have used the factory recommended AC-Delco plug both times.
 
I'd put the 41-962's in and not look back.
They're double platnum's, so I'd change them out at 75k.
Since everything on your 'vette is bone stock, may as well put stock plugs in too!
 
at the time i purchased the 41-962 i didn't realize there was and iridium upgrade as a TSB. I only purchased the 41-962 because the car came factory with Dbl Platinum plugs. Since ive done some research and most Guys on LS1-tech run either Tr-55 Ngk copper plugs or they run An iridium Plug.

Of course all those post are pretty old post. Also doing a little research it seems the 41-962 is a relatively new plug part # to the Ac Delco line? Basically i bought the platinums and jumped online to get gap specs, and torque specs for the plugs. while reading through some post it was apparent Ls1 guys seem to hate platinum in these engines. Most swing toward copper if you dont mind changing them every 30k or Iridium if you want to run them 100k miles.

basically what I've gathered from the info I've read is that Copper is the best conductor, Iridium is pretty good but pricey and platinum is not as good as either of the other two. Also i pulled one of the 41-952's out earlier to look at it and they are not fit to run another 50k miles. the car has 50k on it now and the plug looked pretty rough. it also was at a gap of 0.72. factory used to be 0.60 before it was back spec'd to 40.

so i was debating on going with tr-55's as i have ran tr6 NGK plugs in a boosted mustang and was very happy with them. and if the platinum's really only hold up decent for 50k miles so far why not just use the NGK's? what are your thoughts on this? Im not opposed to buying Iridiums, but i also know that just Because Gm backspec'd all models to iridium doesn't mean that it is the only good choice. Many Ls1's were happy long before iridium plugs were available for it.
 
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Originally Posted By: doitmyself
Why would you not follow GM's recommendation for the iridium plug in their 2004 TSB regarding this?

http://forums.corvetteforum.com/c5-tech/2456040-spark-plug-question-ac-delco.html

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=874572



doitmyself, i figured out why i did not act on this bulletin when i read it a couple days ago. 41-985 has been superseded by 41-110 i think ill go exchange my platinums for the 41-110's tomorrow so ill be ready to swap this weekend
thumbsup2.gif
Thanks!
 
Originally Posted By: The_Eric
Looks like the 41-985's are recommended in the TSB. Why wouldn't you run those?


Yes, but that bulletin is from 2004. 41-985 has been superseded by 41-110. I exchanged the 41-962s for the 41-110s this morning. I lucked out as the 41-110 are on rebate at AAP so when I returned the 41-962s and got the 41-110s it actually was cheaper! So glad I held off on installing the 41-962 platinums.
thumbsup2.gif
 
Whatever you use, the #8 plug will be the worst. I'm tall, and had to lay on top of the engine and come at the plug from the top.

Good luck.
 
Originally Posted By: Mr_Incredible
Whatever you use, the #8 plug will be the worst. I'm tall, and had to lay on top of the engine and come at the plug from the top.

Good luck.



He has a C5 (y-body, NOT f-body), or are you talking about 5th gen Vettes??

donny; like A Harman has stated for OUR cars (f bodies), IF they are a pain to change on a C5 (I do not know, as I've NEVER done them on a Vette), go with the longest lasting plug you can buy.

If not you CAN use the TR55s, and it will run fine for `30K miles.
Some f body owners do use the TR55s, but they are usually the ones who have long tube headers and NO emissions equipment to get in their way, and butcher their arms and hands during a plug change, so doing this 3x as often is not a big deal.
wink.gif
 
TR55's. Better performing, and easier on coils than a platinum plug. Change them every 20-30k (or more if the cars making a bit more power).
 
I would never use a copper plug in place of an iridium or platinum, just because I want to avoid doing the same job in the future. Does the plug type really make THAT much difference in ignition coil life? The ignition coils were built to use platinum plugs, so unless the ignition coils have some design flaw, I don't see the point in using copper plugs.

So I would either use the OEM plug, or the plug specified in the TSB.
 
the latest 41-110 Ac-Delco Iridiums are installed! same plug used in the newer ls3 cars. gapped 0.040. car runs fine. Reduced a little of the high rpm spark knock it was having. Car is headed to the dealer on friday to have the ECU reflashed with the flash that eliminates the common spark knock on some early 98-02 Ls1 powered vehicles. Apparently some ECU's came from the factory with a little too much timing on some models.

I checked online to see if my car was missing any reflashes and it was missing two. one being a GM reflash for spark knock. The dealer knew exactly what i was talking about so i guess it was pretty common on stock LS1's I also replaced the PCV valve while i was in there. Tune up was a breeze. took me 45mins. used anti-seize, dialectic grease and torqued each plug to 132inch pounds..11ftlbs
 
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Originally Posted By: donnyj08
the latest 41-110 Ac-Delco Iridiums are installed! same plug used in the newer ls3 cars. gapped 0.040. car runs fine. Reduced a little of the high rpm spark knock it was having. Car is headed to the dealer on friday to have the ECU reflashed with the flash that eliminates the common spark knock on some early 98-02 Ls1 powered vehicles. Apparently some ECU's came from the factory with a little too much timing on some models.

I checked online to see if my car was missing any reflashes and it was missing two. one being a GM reflash for spark knock. The dealer knew exactly what i was talking about so i guess it was pretty common on stock LS1's I also replaced the PCV valve while i was in there. Tune up was a breeze. took me 45mins. used anti-seize, dialectic grease and torqued each plug to 132inch pounds..11ftlbs



Not to mention they were probably tuned a little closer to the edge, and were fine on 87 octane of 1999, but with todays [censored] gas with a higher ethanol content....
 
Originally Posted By: donnyj08
the latest 41-110 Ac-Delco Iridiums are installed! same plug used in the newer ls3 cars. gapped 0.040. car runs fine. Reduced a little of the high rpm spark knock it was having. Car is headed to the dealer on friday to have the ECU reflashed with the flash that eliminates the common spark knock on some early 98-02 Ls1 powered vehicles. Apparently some ECU's came from the factory with a little too much timing on some models.

I checked online to see if my car was missing any reflashes and it was missing two. one being a GM reflash for spark knock. The dealer knew exactly what i was talking about so i guess it was pretty common on stock LS1's I also replaced the PCV valve while i was in there. Tune up was a breeze. took me 45mins. used anti-seize, dialectic grease and torqued each plug to 132inch pounds..11ftlbs


How did you check to see if your ECU is missing reflashes?
 
Calid.gm is the official GM recalibration site. You can type in your vin and find out which reflashes that have been issued for your vehicle, if any! You can then print of the results and take them to your GM dealer. If your vehicle is out of warranty you will have to pay the hourly rate for calibrations. I was quoted 160$ for all 3 updates my car hasn't received.
 
I will go with the 41-110s on my next plug change as well.

They are more likely than not made by NGK.
I wonder if they are the IXes, or the Lasers under the AC Delco label?
21.gif

(I'm guessing the latter, given that they rate them for 100K miles.)
 
Originally Posted By: dailydriver
I will go with the 41-110s on my next plug change as well.

They are more likely than not made by NGK.
I wonder if they are the IXes, or the Lasers under the AC Delco label?
21.gif

(I'm guessing the latter, given that they rate them for 100K miles.)



i wondered this as well. The plugs say assembled in the U.S with quality Japanese parts right on them around the hex area. Im pretty sure they are NGK's made for AC-Delco. The ends of the igniter are a blue color with a gold colored tip. I should ask to look at a NGK TR5IX next time im at AAP and see if its virtually the same plug... The laser cut NGK's run a few dollars more than both the AC-Delco and the TR5IX plug so im guessing they are just IX's. no doubt still a nice plug for $6 each
 
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