3.5 EB spark plug design update ‘22+

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ayoustin

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Indexing plugs is generally for efficiency reasons when being used in OEM applications. The only other production car I'm aware of to use indexed plugs is the first generation Honda Insight. Honda stamps the cylinder head with a letter by each plug hole for what plug is needed to get the ground strap oriented correctly. I've seen Insight owners say they've had significant changes (a few MPG) in fuel economy going from correctly indexed plugs to non indexed plugs and vice versa. Those Insights are highly sensitive cars though (it gets over 70mpg for crying out loud) so small changes make a big difference, I doubt it would be nearly as noticeable of a difference on one of these trucks.

I'm honestly very surprised to see Ford do this though. I would imagine with modern manufacturing they can get the threads in the head oriented the same for every hole so they don't need to call out different part numbers for different indexes like Honda had to 25 years ago. I'd also wager that most aftermarket plugs won't be threaded the same every time as an OEM plug, so unless you want to mess around with indexing washers stick to OEM plugs.

index.PNG
 

SurfRaptor

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Indexing plugs is generally for efficiency reasons when being used in OEM applications. The only other production car I'm aware of to use indexed plugs is the first generation Honda Insight. Honda stamps the cylinder head with a letter by each plug hole for what plug is needed to get the ground strap oriented correctly. I've seen Insight owners say they've had significant changes (a few MPG) in fuel economy going from correctly indexed plugs to non indexed plugs and vice versa. Those Insights are highly sensitive cars though (it gets over 70mpg for crying out loud) so small changes make a big difference, I doubt it would be nearly as noticeable of a difference on one of these trucks.

I'm honestly very surprised to see Ford do this though. I would imagine with modern manufacturing they can get the threads in the head oriented the same for every hole so they don't need to call out different part numbers for different indexes like Honda had to 25 years ago. I'd also wager that most aftermarket plugs won't be threaded the same every time as an OEM plug, so unless you want to mess around with indexing washers stick to OEM plugs.

View attachment 420209
So essentially, if I wanted to change the plugs in my 22 I would have to simply remove and then reinstall without dropping or damaging the plug during install and then torque to spec. Isn't this what everyone was mostly doing anyway when installing plugs? In my 08 wrangler, you definitely didn't need to torque to spec (index) the plugs but torquing to spec seemed easy enough to do anyway as long as you had the tool in your box. Am I missing something here? Working with the raptor after 14 years of Jeep is a lot different, lol.
 

m6ar2cel6o

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Can anyone confirm these plugs work for gen 3s? Ford Racing (M-12405-35T) 10-17 Flex 3.5L EcoBoost Cold Spark Plug Set
 

Lanthas

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Can anyone confirm these plugs work for gen 3s? Ford Racing (M-12405-35T) 10-17 Flex 3.5L EcoBoost Cold Spark Plug Set
I am using these same part number plugs on my Gen 3. Bought them from Goosetuned when we did the tuning last year.
 

SurfRaptor

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I'd love an update as changing the spark plugs is a job I plan on doing at 30k on my gen 3. Many will say its early, but I could always feel a different in my JKU with new plugs. It improved HP and gas mileage. I'm also looking into cleaning the throttle body if anyone has any advice for that job also.

This is the single replacement plug I am running right now for my Baja tool kit. Is this incorrect?

 

FordTechOne

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Ford changes the recommended replacement plug for the 3.5L EB about every 6 months it seems.
No they haven’t. The spark plug replacement interval hasn’t changed since the engine came out in 2017. It’s 100k under “normal” conditions and 60k under “special” operating conditions.
 

EricM

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No they haven’t. The spark plug replacement interval hasn’t changed since the engine came out in 2017. It’s 100k under “normal” conditions and 60k under “special” operating conditions.

I didn't mention the word "interval" smart guy.

I am referring to the plug itself- the SPXXX of the month flavor. 534s, 580s etc
 

FordTechOne

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I didn't mention the word "interval" smart guy.

I am referring to the plug itself- the SPXXX of the month flavor. 534s, 580s etc
There are only 2 parts numbers for 2017-2020/2021; the original - SP578 - and the supersession, SP 594.

2021 3.5 built after 7-19-21 use SP596, which are gasket seat instead of tapered seat and use an indexed ground electrode.

You’re exaggerating as usual.
 
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