zinzin,

i'm starting to believe that people are reading what they want and not what is written.

concerning the Northstars, my gut feeling is that a N* will go 250,000 to 300,000 miles without much
maintenance, including running the OEM plat plugs for that long, as long as:

1. change out the coolant at 24 month intervals,
2. change oil as required by oil monitors,
3. routinely replace all little things that fail, like coils, primary wires, etc ..,
4. run engine until it warms up well,
5. clean out the coke deposits on the intakes and make sure it doesnt build up on the piston rings.
6. dont race it every day.

I only change spark plugs ONCE on any car and that is only to the end of installing dual plat plugs for the
life of the engine. I have never every replaced OEM dual plat plugs and dont expect I ever will.
Whether GM or Lincoln/Ford, same practices.

the trani .. well, that is another subject.

 

Ah but you didn't read my post. I would almost defy anyone from "trying" to get out a set of plugs from an aluminum block after say five years and 100,000 miles. I asked the service manager when my 96 Voyager was in for service at 50,000 miles and three years about this same question. (The Voyager had 100,000 mile platinum installed plugs) He asked me how the car was running and suggested I go for another year and 15,000 miles more because so much of the engine had to be removed to get to the rear plugs (intake manifold and some injectors.) Said they werecausing more problems aftera plug change. But he did agree with me about "pulling" them at 65,000. Not because of the plug life but because of "plug freeze."
I know that you would make sure that a well lubed set of plugs would go in any work you do but not so sure this occurs in the factory asembling mass produced engines.
I've encountered just to many frozen plugs over the years of rebuilding engines.

 

I did read it. That being my point. Other than curiosity, why remove them, ever?
Unless the car ended up with cheap single electrode plats, installation was not done well
or is questionable, or car has problems like overheating.

Another reason to pull them? buyer demands a compression test. Now you possibly got a problem
if the factory didnt do the job OR over-torqued them.

If the engine has to come out, then it makes no difference.
Once the engine on a stand, we got ways to get plugs out, frozen or not.

Last year I had to deal with a 6-cyl import where someone "removed" the plugs cuz the manual
said 100,000 miles and an electrode broke off - he didnt bother to get it out. That plug change,
that was really not needed cost the owner the whole engine - $3,500 rem.

As you eluded to, a proper lube (I use anti-seize) of the threads is a must to avoid that.

Lastly, if it was a newly acquired car on my hands, I might be tempted to "inspect" or replace the plugs.

 

From my experience removing spark plugs from aluminum headed GM engines that were factory installed and undisturbed for 100k+ is not that big a deal. It's plugs that have been removed and re-installed or replaced without anti-sieze and/or improperly tightened that are. I know Ford 4.6 has some concerns. I have no info concerning Chrysler. To me replacing plugs on rear head of 4.1,4.5,or 4.9 especially the 86-92 E/K & V bodies that are most challenging. 4.5 pfi with its AIR pipes are the worst of all them.

 

May I assume that the challenge you experienced is due to access ?

 

Cut hands, fingers, wrist and forearms, doing them on the ground. Cuts and occasional burn from exhaust on a lift. Many times getting plug wire boot off plug is a challenge. Sticking boots lead Cadillac to come out with special coated spark plug, to help combat problem.

 

I believe "access" is the reason platinum plugs were designed. The first I remember were for a Pontiac??? that was designed for the new Wankle engine. The Wankle could not contain "seals" and a small V6 was subsituted. Wouldn't quite fit and engine had to be raised to get to the rear bank of plugs so platinum were installed in the rear. This was to far back for me to remember model of car but I'm sure these were the first long life platinum plugs.

 

zinzin,

here is a site that should keep you busy on them snowy nights.
http://rstreet.us/sparkplugs/index.htm

is this the 1st one ?

 

Spark plugs are the most boring subject in the automotive world. A little like brands of oil. Someone will come up with the car name. It was sporty and produced for several years with the V6. My guess would be "mid seventies" when the "Wankle" was supposedly "revolutionary."
I used to have to pull over about every 700 miles with my XK 120M in the early fifties and remove and wire brush 6 plugs when the engine started "missing." No big deal, and well worth it. With a spin wrench on that engine, took less than five minutes. After a while I just purchased a spare set and the replacement time got down to three minutes. My wife got used to it! So much for the "leaded gas" at that time.
Was part of the "ritual" during pit stops at races then. Two outside tires and a set of plugs in less than a minute. (A simple operation with those "Offies.")