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View Full Version : 100,000 mile iridium plug test


leiniesred
01-21-2010, 09:00 AM
I know I changed my plug wires when I got the truck in 1996. Around 123,000 miles.

I think I changed to NGK iridium plugs one plug change after that. Call it 150,000. Maybe 1999? I put in iridium plugs thinking there was no way my clunking engine would make it another 100,000 miles. I thought it was my last plug change on the truck!

Last night, at 273,000 miles, I put on a set of Jacobs 8mm plug wires that I've had kicking around the garage for about 5 years. I also put on a set of normal NGK V-grooves plugs.

I did NOT put anti-sieze on the NGK iridium plugs 10 years ago! (part of the test!) # 3 and 4 were hardest to remove. I just took my time and cranked them back in a bit when it got hard to un-do them. Eventually they came out without messin' up the threads. I suspect it was carbon stuck on the threads that were exposed in the combustion chamber. No big deal.

Looks like I'm buring a little oil based on the white deposits. Not a shocker at 273,000 miles. The deposits are mostly on one side, so that usually means valve guides/seals, but I think it is actually coming right in with the intake charge. The throttle body is pretty wet. Probably stuck PCV or just plain and simple blow-by.

Performance result of the new plugs/wires? Seems about the same. Only the big run up I-70 tells me if there is a power difference. (how soon I have to shift into 3rd gear!)

Jacket
01-21-2010, 01:06 PM
You didn't put another set of 100k mile iridiums? That engine's proven you wrong so many times now....

DaveInDenver
01-21-2010, 01:19 PM
I love it, electrodes that look like cones. Cool.

nakman
01-21-2010, 04:11 PM
That engine's proven you wrong so many times now....

:lmao: :lmao: :lmao: :beer:

J Kimmel
01-21-2010, 04:49 PM
You didn't put another set of 100k mile iridiums? That engine's proven you wrong so many times now....

nothing else to say:rolleyes: