Plugs and wires.

[jeepgclwj]

I am in the process of changing plugs and wires. How can I tell if they are the factory plugs and wires.

I changed my plugs on my Jeep the other day and the wear on them is different than on my GTP. 0.040 is the gap for my Jeep and the old ones were measuring .060-.062 I assume due to them wearing down to nothing. The plugs on the GTP have the same .060 gap as I am supposed to use but they are wore toa point instead of a nub. Does this make sense to anyone on why they would wear like that.

I am wondering out of curiosity only I have not run into any problems yet.

[GTP Dad]

The wires would be marked with AC Delco or GM. The plugs would be more difficult to tell as they may have been changed many times. GM uses AC Delco plugs as original equipment. As for the wear it is difficult t say why they would wear in this way. It could be caused by normal firing of the plugs. As long as the electrode is there you aren't having any issues other than normal wear. If the plugs were new and you pulled them after a couple thousand miles and they looked burnt or like this you may have a problem with detonation.

[jeepgclwj]

Well, I have run into a small problem. The number 6 wire. Is there a secret on how to pop the plug wire off? There is something in the way of it. Do I need to somehow remove that thing? It looks like it goes into the driveshaft or something, I dunno. Once I do it the first time I will be able to do it for life. So you guys dont have to ever worry bout helping me on the same thing... I hope

[BNaylor]

High probability you do not have the OEM spark plugs and wires but you never know for sure until you check them out.

Back in 1998 the igntion wires were marked with the name Packard spaced out in intervals and will have the marking for the cylinder (1,2,3,4,5,6) it went to since each length of wire is custom fitted. The AC Delco 7mm Premium Silicone wires that are now recommended for use do not have the cylinder number markings and say AC Delco.

The OEM spark plugs from the factory were probably AC Delco 41-921. These are double platinum meaning both the ground and center electrodes are platinum. The plugs were advertised to be good for at least 100K miles. I have pulled OEM platinum spark plugs of the 41-921 variety at over 90K miles and noted little or no visual wear of the electrodes and the gap was consistent at .060".

[MT-2500]

Originally Posted by jeepgclwj

Well, I have run into a small problem. The number 6 wire. Is there a secret on how to pop the plug wire off? There is something in the way of it. Do I need to somehow remove that thing? It looks like it goes into the driveshaft or something, I dunno. Once I do it the first time I will be able to do it for life. So you guys dont have to ever worry bout helping me on the same thing... I hope

I do not think there is a drive shaft near it.
Make sure you are on the plug wire.
The 02 sensor goes into the exhaust pipe in that area.
If you can get your hand on the wire where it plugs onto the plug twist and wiggle a little and pull.
Or if you can grab the boot with a pair of pliers twist and pull.
They can be a pain but just keep working at it.
If at first you do not succeed take a break and the have at it again.
Good luck MT

[BNaylor]

You should have the metal heat shields over each boot? Do not grab those with pliers because you will damage them. They are used as heat shields and for anti-static suppression.

What I do is remove the 02 sensor which is in the way to remove #6 spark plug. That way you give your hands more area to work for leverage. With engine cool grab the heat shield with your hands and pull hard until shield and boot come off the spark plug. With patience and you should get there.

BTW - When you install the wires make sure you coat the end of each spark plug (boot side) with dielectric silicone grease that way they will come off easier next time around.

[jeepgclwj]

Well I got all six spark plugs out and replaced. I will work on getting the new wires on tomorrow. I tell you what, those plugs dont look to good, really dark and dirty. NKG PTR4B-15 were the plugs I took out and I put the Autolite back in.

Should I take the Duralast plugwires that I bought back or use them? I was kinda short on cash when I bought them last week. What difference would I see using something else.

Also, what made that number 6 plug easiest for me was climbing onto the car. I put my knees on the mounts and leaned in over the engine. I wont say it was a piece of cake but, I didnt have to take out the o2 sensor....My car did have the metal boot over the plugs...

thnx everyone,
Chad

[BNaylor]

Use the AC Delco Premium Silicone 7mm wires. Best on the market. Or the Taylor Spiro Pro 8mm. I'd can the Duralasts. Which Autolites did you decide to use and what heat range?

Removing the 02 sensor is easy with the right tool. 1 minute job. I'm too old to be sitting on the top of an engine but at least you got it done.

[jeepgclwj]

I used the Autolite Platinum-AP606. I just looked at the thread in tips and maintenance it looks like I should have used copper core, I hope that I didnt screw up. I will take the Duralst back and get your recommended ones. Will I be screwing anything up running the platinum ones? If so maybe I should change them out as well.

The o2 sensor looked to be about 7/8" and everytime I got my wrench in there I couldnt see what I was doing. Trust me I had no buisness up there like that but got to do what you got to do....

Looking at the plug wires they are numbered 1thru 6 so I assume those are factory. If the plugs were not factory because they didnt have AC Delco or GM on them that would mean that they have been changed at least once. The car only has 76,000 miles on it. What would cause the second set of plugs to look as bad as they did. Could the previous owner ran low octane gas or could there be a problem that I should look at or am I being paranoid?

Chad

[BNaylor]

You are fine with the Autolite AP606. I use them in my stock L67 Regal GS. Works fine. BTW - My gas mileage increased using them.

When you mod with a smaller supercharger pulley then use the Autolite Copper Core - 606, 605, 104, 103 to keep knock retard in check. The AL AP Platinums will last longer for the time being.

The 02 sensor is 7/8" but you need a special 02 sensor socket with the cutout for the wiring harness used with a 3/8" drive ratchet and short extension. Around $10 at Autozone.

Plug wires if numbered look stock OEM. I'd have to research the heat range and type NGKs used but they don't look OEM AC Delco. But the AC Delco Iridiums (41-101) are made by NGK and that number sure looks similar which is stamped on the metal base by the threads.

My plugs are a perfect light tan/brown. But they are AL Copper Core 103. 3.0" SC pulley. Put the right ignition wires in then take a plug reading off a few of the odd bank plugs (easy to get to) and see how they look. Good luck.

BTW - Even with only 76K miles the ignition wires will need replacing sooner or later.

[richtazz]

Those NGK's were used from the factory in the GTP's due to shortages from Delco (Delphi in Flint actually produced plugs for NGK, and the 3800 assembly plant used those marked as NGK when supply of Delco marked plugs ran short). Just a note, now that spark plug production has ceased at Delphi here in Flint, MI; most Delco Platinum and Iridium plugs will be manufactured by NGK, with Nippondenso producing the rest.

[BNaylor]

Originally Posted by richtazz

Those NGK's were used from the factory in the GTP's due to shortages from Delco (Delphi in Flint actually produced plugs for NGK, and the 3800 assembly plant used those marked as NGK when supply of Delco marked plugs ran short). Just a note, now that spark plug production has ceased at Delphi here in Flint, MI; most Delco Platinum and Iridium plugs will be manufactured by NGK, with Nippondenso producing the rest.

That makes sense Rich. Looks like NGK's version of the AC Delco Platinums. Classified as double platinum, extreme long life. Same gap at .060".

[jeepgclwj]

So it sounds like those were the stock plugs on my car, huh? That would explain the bad shape they were in. Were these cars supposed to go 100,000 miles before a tune-up? In any case they are garbage now. Once again you guys have been helpful and I thank you..

Chad

[BNaylor]

Yup, 100K miles according to GM.

But I've seen the AC Delco Platinum counterparts in relatively good shape even with at least 90K miles.

[MT-2500]

Originally Posted by jeepgclwj

So it sounds like those were the stock plugs on my car, huh? That would explain the bad shape they were in. Were these cars supposed to go 100,000 miles before a tune-up? In any case they are garbage now. Once again you guys have been helpful and I thank you..

Chad

Sometimes they do and sometimes they do not.
I have saw some go over 125K and some do not make it to 90K
A big foot and hard driving may shorten the life of them.
But a lot of other things may also need to be checked before 100K.
Making the 100K tune up deal a bunch of bull that miss leads people.
Gm said the pink Dex cool would make it 150K or 7 years to. But???

Good luck with it.