Hey everyone! Car is a 00' M6 with 96k. It still has the original plugs along with the wires.

I was considering changing the plugs for these NGKs as quite a few of the threads have recommended this brand.

https://www.oreillyauto.com/detail/b...corvette?pos=2

And the wires for one of these

https://www.summitracing.com/parts/s...model/corvette
https://www.summitracing.com/parts/s...model/corvette

My questions are:

Are these plugs likely nearing their end of life?

Are the wires nearing end of life? 20 years is plenty of time for oxidation to wear them and things are still working, however, I am not sure how well they are working.

Does 50 ohms Vs 270 Ohms result in a measurable difference in spark? I ask because these wires are rather short and I think the engine would look rather dashing with the red accent of the 270 ohm wires. The black ones work fine if 50 ohms is really worth it.

I know these upgrades won't result in much extra power, if any, however, in theory, is it correct thinking that lower resistances would result in more accurate timing due to more responsive components?

If I change the wires should I add some thermal sleeves? I do have LT headers. I was looking at some titanium sleeves from Design Engineering.


Thank you for reading, you guys are always such great help!

 

I feel the 100k mile rating on the factory plugs is modest. I've pulled them and they have looked great with no issues. I replaced them anyway along with wires. Absolutely no noticeable change in power or fuel economy. I'm also running long tubes and using the dei sleeves. I would recommend using sleeves just for the peace of mind.

 

If you are going to replace the plugs you may as well get a new set of wires also.You will more than likely tear a couple of them up while removing them.The factory wires and plugs are reasonably priced and readily available.They are as good as any you can find and with them lasting100k miles,why not replace with the same?As far as the heat sleeves,VERY cheap insurance and highly recommended with headers

 

The original double platinum plugs have a noted tendency to lose the occasional ground electrode platinum pad. On my 99 about half the plugs had the pad, the other half did not. Gaps on the order of .080! I'm running the same NGKs, as are many others on the forum. The most common replacement plug wire recommendation around here are the GM Performance, #12495519. May have less resistance than the red wires you noted, probably about the same as the black, but definitely designed to work with the factory heat shields.
Other suggestions: (Amazon links are just where I found things, and show what each looks like)
GearWrench 80546 5/8-Inch x 6-Inch Swivel Spark Plug Socket. A couple of the plugs are a bear to get to, this socket makes it much, much easier, and it's a magnetic hold on the plug, instead of the foam rubber that pops out of other plug sockets -- even some of the expensive ones.
Lisle 51410 Offset Spark Plug Boot Removal Plier. The odds are extremely high that many of your plug boots have bonded themselves to the plugs in the 20+ years they've been together. An offset ring nose plier makes quick work of breaking them loose. Although, at 20+ years the odds are also quite high of coming off in more than one piece.

 

Just an FYI,the new replacement AC Delco plugs are iridium.They no longer have the platinum puck that has been known to"disappear".

 

I think the 100k recommendation is more about replacing them while you can still get them out rather than the plugs wearing out. I changed plugs on wife’s Impala SS with 5.3 at 150k. None of the plugs had much wear. Plugs on the 4 Displacement on Demand cylinders were full of carbon. Couldn’t believe they were still firing.

 

After 20 years like you said, may as well begin the restoration process or build.

 

I decided to change my plugs and wires because it was a used car, I didn't know the condition of the plugs and wires, and I figured with the new stuff , it couldn't hurt,

I wanted to look at the plugs anyway, and I would have a record of when the plugs and wires were last changed, andI didn't mind eliminating any questions about function.

I also come from a time when build technology was very different, changing plugs was a usual deal to keep the heaps running ok, so I might have had some old long unused neural pathways influencing my decision to fix something that wasn't a problem. 1000,0000 plugs would have been science fiction back then.

Mark the old wires for location , the wires are very similar in length, but are slightly different.

I have been very happy with the GM red wires and plugs, and the later specs for the plug gap smoothed my idle a bit. From reading , I was told the GM stuff is a perfect fit, and it did snap on correctly without trouble, but I can't say how they compare with other wire sets.

my plugs might have been through some shipping trauma, they are supposed to come pre gapped, but two of them were off, and
I used great care to measure the gap and the set the distance without working with the finished tip surface as it is very brittle or scratching the electrode. I bought them from a supporting vendor rather than over the counter.

good luck , bring extensions and swivels .

 

I'd change both def at that mileage. You won't necessarily gain power, but you might recover some lost power. Many on ls1tech have gone MSD Ignition wires, including me, with great results. I don't know about Summit wires. You might gain a few ponies going to a hotter copper plug (like TR55's), but you'll have to change them out more often..

 

Talking with several engineers who worked on the LS1/LS2/LS3/LS6 from my local club, they indicated the spark loss from the short OEM wires was very minimal that any good 7/8 mm plug wire will be good. They were more concerned on the size of the wire if you had headers. They included several W2W racers, GM test engineers, etc. that most knowledgeable performance Corvette and racers would know.