100K sparkplugs at 40K

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These are 3 of my 6 plugs out of the G35. They are supposed to be 100K iridium plugs. This is after about 40K. All 6 look about the same. I am pretty sure they would not make it to 100K. This is my fourth set of plugs in this car.

They are one heat range cooler than stock, but otherwise the same plug.

I put a new plug in one picture so you could see the electrode wear. Being iridium, these can't be gapped.

infplugs007copy.jpg


infplugs004copy.jpg


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Those look like they've been eroded.

And, I've gapped iridium plugs. Use a feeler gauge and an old-school spark plug tool to avoid damaging the iridium tips. Re-gapping the plugs on the Cruze did wonders for drivability.
 
I don't know anything about the engine in the G35.

I'm curious why you went with the cooler plugs? Is this a typical thing among those who have a lead foot? Did you have pinging?

Inquiring minds want to know!
 
I had problems like this when I went to colder plugs, I did it because of some claims on other forums. Do you have a tune that requires them? Otherwise, as I learned, stick with stock heat range.
 
I would try a double platinum plug in the VQ engine. It appears like there is excessive ground erosion.
NGK Laser Platinum PLFR5A-11 is double platinum.
At 50K they look great.
 
Let me guess, NGK plugs and city driving.

You can drive 3 miles on hwy for every hr of city driving (engine hrs wise).

Also, NGK iridium have no precious metal on the ground electrode, leading to erosion.
 
Originally Posted By: CBR.worm
Being iridium, these can't be gapped.

Yes they can. You grab the sides of the top electrode with pliers to do the bending.
 
I think something else is going on with this engine other than plugs. If you are running colder plugs, I have to ask why? How many miles on this engine?
 
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Indeed, unless it is boosted (and running more boost) or on the bottle, it would seem that the colder plugs aren't helping, judging by the generous deposit formations taking place here.
 
Those only look like single iridium plugs. Those will wear much sooner than a double platinum or iridium plug.
 
Originally Posted By: friendly_jacek

You can drive 3 miles on hwy for every hr of city driving (engine hrs wise).


LOL! I meant you can drive 3 miles on hwy for every mile of city driving (engine hrs wise).

Thus, 40,000 miles of city = 120,000 miles of hwy give or take.
 
I don't know the engine, but looks like it would be waste spark - the wear on the ground electrode is because the spark is jumping from ground to centre. I'm picking the other 3 should be looking good. Fit double plats and they will last the time.
 
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