GEN 2 Spark Plug Change - How Often?

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EricM

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Currently no tune but I changed them since goose recommends colder plugs and changing them if you don't know how old they are.

I torqued to the recommended 11 lbs which feels less than turning an old door knob. I've never installed spark plugs that required to be so softly tightened I wonder if it could be too loose. It felt like some dirt in the threads can make it appear to be torqued down but who really knows.
Dirty threads can give you false torque readings. Get a thread chaser for next time. (Not a tap!).
 

JCT

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I think the 3.5L is similar to any other turbo motor. If you are going to push boost and timing with a more aggressive tune, you are going to have to change the plugs more often. I change mine every 15k or so in both my Raptor with a MPT tune and in my GLC63 with a stage 2 Eurocharged tune. Both of them run noticeably better after a plug change. Could I probably get another 10-15k miles out of them both without a plug change, maybe. But, that will put more stress on the coil packs and increase the chances of having an issue.

Just my 2 cents.
 

Reaper308

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I changed mine at 45,000 and they were toast I’m going to a 15,000 change rate and see how that works!
 

EricM

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Yes, all new trucks come with platinum spark plugs as standard equipment. Platinum plugs easily last 100K miles. After that the gap starts to erode beyond spec which puts a higher load on the spark plug's coil, how long they last after that is anyone's guess but I've seen plugs last 200k miles.
I think you mean iridium fine wire plugs. Ford has been runnning those as OE plugs in everything for over a decade.

A platinum / double platinum plug has a thick center electrode with a flat head.

An iridium fine wire plug has an electrode that looks thin enough to poke into your skin. The iridium coating is the only reason that tiny electrode survives at all, let along over 100K. The ground strap is platinum plated, so I guess it's kind of a platinum plug- but not what most people consider a platinum plug.

Platinums are a genration old now- it's harder to jump the gap on a platinum vs an iridium (fat elctrode vs pointy electrode) and worse yet they don't last as long.
 

mad man

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Here’s a mystery just changed my plugs Five of them look the same. One of them is missing half of its porcelain WTF. Look closely to the plug on the left. They all have the same miles on them. That’s the way it came out!!
 

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EricM

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Here’s a mystery just changed my plugs Five of them look the same. One of them is missing half of its porcelain WTF. Look closely to the plug on the left. They all have the same miles on them. That’s the way it came out!!
Is one from the top plugs and the other from the side plugs?

It's probabaly an irririum plug in one, and a platinum in the other if I had to guess. It's likely the spark jumps from the ground strap to the electrode on the irridium, but on platinum it jumps from the electrode to the ground strap. No need for irridium on the platinum style since the sparks erodes the large ground strap instead of the small electrode. Installing platinum plugs that are fired on the "waste side" of the coil in place of irridum plugs in hundreds of thousands of vehicles saved Ford a lot of money, and did not hurt performance at all.
 
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