defcon(ls)1

iTrader: (1)

on my 1998 Trans Am (1st owner took delivery in 9/1997).

Car runs great with great gas mileage. So there's no motivation there to swap out plugs.

But I heard maybe keeping plugs that long in alum. heads could be asking for trouble with regards to seizing in the head?

Any thoughts on plugs in alum. heads for 10+ years?

Thanks.

johnson7454

iTrader: (3)

you need to take them out and put no seize lube in there. They can lock there self in there. You can buy a little package from the parts store for like a buck. You just need to lube around the threads and everything will be fine. But if they are the same plugs from the factory i would replace them with some stock NGK's.

Roadhouse

iTrader: (8)

If you decide to at least see what the plugs look like, set aside a good portion of your afternoon to do it. It took me 3 hours the first time to change them out.

pjb

iTrader: (2)

mine were in my 98 until a little over a year ago. 125k miles, still running fine. They were very difficult to break loose, but spun out freely after that. They are so hard to change that it would be foolish to put the old ones back in. always use anti-seize wth aluminum heads.

defcon(ls)1

iTrader: (1)

Thanks so much.

Greggy

I would not touch them. You are more likely to break the wires or something else trying to get them out. Check the easiest one to get to, and if ok then go another 30k and check again.

Mine were fine at 85k, but put in new AC irridiums and MSD wires.

On a stock motor that is running good, the plugs really do last 80-120k. Most likely they will come out fine...mine did.

Medic/Z28

iTrader: (9)

Mine only gave me 45,000 miles of life. They we're bad. This was years ago. Spring of 02. I have a 2000 Z that I bought new.

tripps

iTrader: (7)

Believe it or not my car got its first spark plug change this weekend when I did headers. 114k miles and still runs great. Of course it runs even better now with MSD, NGK and the headers.

You should be fine until at least 60,000 miles. Then you can try changing them out.

ghardester

[QUOTE=Greggy]I would not touch them. You are more likely to break the wires or something else trying to get them out. Check the easiest one to get to, and if ok then go another 30k and check again.

Yeah, because once you start yanking on old wires just to check a plug you might need to replace them. And if you decide to pull more than one, just wait and have all new wires and plugs on hand and change them. Just leave it alone then.

defcon(ls)1

iTrader: (1)

I got some AC Delco Iridiums and the box is pictured here. There are two numbers on the box:

8#41-985 <-- written big
12571164

I will also get new OEM wires.


I also found this off the web concerning these plugs. Note these plugs should be kept at 0.040" gap vs. the stock 0.060" gap.

"A new spark plug has been released for use in the above vehicles. The new spark plug has an Iridium tip instead of the current Platinum tip. Due to the different tip design, the gap of the spark plug has also changed. The new spark plug, P/N 12571164 with AC Delco P/N 41-985, is gapped to 1.01mm (0.040 inches) when the spark plug is made. The spark plug gap is set during manufacturing and should not be changed or damage to the spark plug may result. Any new spark plug found to not be properly gapped should not be used."

"The new gap is because they're iridiums instead of platinum. They issued the tech. service bulletin for a reason. The new 0.040" gap and new iridium plug is correct. Check the gap before install. Better yet, bring your gap checker to the store (or buy one at the store) and check them before you go home. If the gap is wrong, don't buy that plug."

defcon(ls)1

iTrader: (1)

I just installed the AC Delco Iridiums (at 0.040" pre-gap) and OEM plug wires in lieu of the original 30,5xx mile platinums and plug wires.

Car is not any faster at my 100% stock engine spec but it's definitely smoother at idle (less gritty feel at steering wheel) and it's pure silk when charging to redline. After comparing new stock platinums in a Lexus ES300 to new stock Iridiums in the same car, I'm sold on Iridiums.