Technical Comment on Spark Plugs

[TripleBlk]

I just changed my Autolite Platinum spark plugs (over 50k on them) for some Autolite 764 (copper cores). I immediately felt a difference in idle quality and acceleration. I changed the original platinum plugs at about 50k, but didn't notice (or don't remember) a difference then.

I don't know why they rate the platinums for 100K, since it's pretty obvious the platinums were "worn out" (though the car "ran")

Anybody else with comments concerning the platinum plugs, especially on how long they are supposed to last ?

 

[Kilgore Trout]

Did you keep the same gap? Post closeup pics of the old plugs.

 

[jeffnoel]

Yeah I'd like to see a pic of the old plugs also.

 

[TripleBlk]

Old set and new set gapped at .052-.055 . Took pics of old plugs ; will post as soon as I find my camera's USB cable (aarrgghh).

 

[TripleBlk]

This site has a limit of 78K ! My pic is 514K - please advise

 

[Dusstbuster]

Photobucket...it's free and you can host a ton of pics.

 

[TripleBlk]

Dusst - thanks man !

here is the pic :

http://s176.photobucket.com/albums/w163/99BlackStang/Stang_Plugs.jpg

 

[CobraRed_96_GT]

i think they meant a close of of the tip. The 2nd from the left looks like it could be white which could mean water or it could mean camera flash.

 

[TripleBlk]

Cobra_Red : I appreciate your comments. I took the pic with a Kodak 2740 ( a decent digital camera) in not so indirect sunlight on my porch.

I did notice the white cast to the tips. In the old days (carburetors) that would mean the engine was running lean. Nowadays, that's not certain.

The point I'm trying to make (weakly, I guess), is that the platinum plugs are rated at 100K, miles, yet replacement with the copper Autolite "el-cheapos" made for a better driving experience. Those plugs have 50K on them (again).

 

[Kilgore Trout]

Copper has a hotter spark than platinum, this is probably the reason for the difference you are feeling. However, platinum is known to last much longer than copper.

Hell would freeze over before I let a plug be in service for anywhere close to 100k miles.

For people who have to pay someone to change their plugs platinum is the most effective metal for plugs.

For a GT owner who can change his own copper is the best metal for plugs.

 

[TripleBlk]

KT - I agree with the points you are making. But, they are still printing owner's manuals with recommended service intervals of 100K. I ignored the 100K interval, too, and changed the originals at 50K.

It sure looks to me as if the platinums last about 30-40K. That being said, I would recommend new copper plugs (due to cost issues, time issues) at 20K or so.

Any other comments would be welcome.

 

[Kilgore Trout]

I agree 2 years or 20k miles for copper plugs.