How would changing the tip material from platinum to iridium really made a difference in the gap distance?

Call NGK Tech Dept [ http://www.ngksparkplugs.com/About_nGK/contactus.asp ] and ask them ... all of their spark plugs regardless if they are V-groove or platinum or iridium, etc are all factory gapped at 0.040" for the LS1/LS6. I didn't research other spark plug brands, but I'd bet you would find the same thing, that they have all gone to 0.040" regardless of plug type.

Go here and look up the spark plugs for the C5 Vette ... they all have a 0.040" gap.

http://www.ngksparkplugs.com/part_fi...t.asp?mode=nml

 

No offense, but I'm not interested in researching the platinum v/s Iridium tip technology, and why GM decided to change the required gap... In any case, it really only applies to a "something close to stock" configuration, because once you start adding power adders, the type plug/gap will change....based on the application.

Good luck on your spark plug quest sir.

 

I have a low milage 2003 stock vert. What spark plugs are in my LS1 now?

 

Yes, we're talking OEM replacement here, and the manufactures like NGK are only concerned about making spark plugs to OEM specs. I've done the research, and passing along what I've found.

The bottom line is NGK - and probably all other spark plug manufacturers - have changed all their spark plugs for the LS1/LS6 to 0.040" by direction of GM / AC Delco. If people still want to use the original GM spec of 0.060" then it probably isn't going to hurt much of anything - but GM changed the spec for a reason. And even though the TSB is written to make it sound like it's just for that specific spark plug, keep in mind they assume people are going to go to the GM dealer and get AC Delco plugs. NGK Teck Dept told me they (and probably all other spark plug makers) received this same TSB info for them to incorporate.

If required spark plug gap distance was dependent on the exact design and materials of a spark plug, then every type of plug and every manufacturer would have different gaps for the same engine ... and we all know that isn't true since the gap will be 0.040" no matter who the maker is or what type of plug it is.

 

You won't know until you look at one. My 2002 Z06 had Denso spark plugs when I assumed it had AC Delco. GM used a couple different vendors over the years of the C5.

 

Since you insist.....let me put it another way......I DON'T CARE....

I only posted the TSB, because fendermender questioned the gap.

Good night Gracie.

 

Yeah, I know you don't care so why you still posting in here?

That's why we are trying to clarify the gap question. The TSB is written with a GM dealer/tech in mind ... not the entire public.

 

Mis-spoke-- should have said "tuner friendly" Because the copper core and standard (electrode and strap)--they heat cycle better and read more accurately---especially just after their 1st cycle The cadium plating also burns a nice mark on the strap to read spark timing and the center electrode produces a nice ring to read AFR
Platinum and so forth aren't as acccurate to read even though they have a copper core--Remember that the "tip and strap " are different than the "standard " materaial and it needs to get rid of heat as well !!!! We find reading irridium -platinum-and multi- strapped plugs extrememly difficult to read---

GM now recc tighter gaps om most ALL of their hi-energy ignitions----It's not because the plug won't fire--But the weak point in the link is the WIRES---The larger the gap--the more the spark searches for a point of LEAST resistance to jump accross--GM has had HUGE wire failures !! however most are out of warranty and hit the complaint dept--That's why they now recc .040 on almost everthing

If you use NASCAR as a referance--They do all they can to prevent failures in endurance racing---They gap their plugs even CLOSER !!! .030-.035--- To prevent wire /coil failures without any loss in HP.
AND trust me----If there were even a tiny HP advantage in usuing E3 or platinum plugs all of them would be using them--but they don't Just plain ol copper core ---standard tip/ strap plugs - provides them with accurate fuel/spark data and failure prevention !!!

 

Wernt most "muscle cars" gaped at .035?

 

YES with old points type distributors but with the advent of hi energy ignitions most all car companies rasied the gap up to around .060 in hopes to clean up the smog and get a better burn--But NASCAR type engines which allow CD and MSD type ignitions still only gap them at
.035 to prevent wire failures

 

Where are you getting this information about the "HUGE wire failures"??

 

From the local Chevy dealer and the parts MGR of the largest wholesale warehouse in our area---The dealer says they sell more wires than ever before( why they came out with a GM Hi perfomance model ) to give the people an alternate product---The parts wholesaler also says that they sell more wires to auto repair business's than spark plugs---
Home repairers often mistake that the plugs are bad when in fact because of the large plug gaps the wires have failed---

 

Big jump in new spark plug wire sales could be because it's almost impossible to remove the wires from the spark plugs without damaging them. This would force the owner to buy new wires, even though they were good before he tried to remove them. That's what happened to me when I went to remove the wires.

 

If I understand correctly, it is your contention, that large plug gaps destroy spark plug wires? How is this possible. Please feel free to be as technical/in depth as required.

 

I think what it is is that the larger gap takes more power to get a strong spark where as the smaller gap will not require as much power so the wires can deteriorate further before you lose enough power to where it will not produce a strong spark.

 

A larger spark plug gap also makes the coils work harder. If the gap becomes too large, the coils may not be able to produce an effective spark, and performance will suffer.

 

Entertaining guys.......

 

All this? Who does a moron like me listen to? Plugs getting changed this winter!

 

LOL

 

Well, I hadn't read this thread for a while. All I know is I put in a new set of Autolite double platinums and wires. They were gapped at a tight .060 out of the box and I had no reason to change that since I had no knowledge of this bullitin. That's why I asked the question.

In any case, the original plugs and wires seemed fine at 71,000. Who knows if I'll ever put that many on. A lifetime gaurantee has a different meaning to a 60yo man. I think I'll take my chances the way they are. Looks like a bit of a PITA pulling them out now that the engine is back in.