Spark Plugs

[axeman_87]

Hey, so I know in the manual it says I should change spark plugs around 120000km. Should I follow this or change earlier. ?

2015 Sport 2.7L 78,000km now.

Would I just get stock plugs or another iridium brand? Also the spark plug boot, I've read out there for the F150s to change the boot, is this recommended?

 

Thanks

[Snox801]

Yes change them now. I change mine every 50,000 and notice a sizable gap change at that mileage. That being said I am pushing mine hard. So yes earlier.

Second stock plugs are great in fact livernois reccomends them. I use ngk one step colder in all my ecoboosts. I went this route as they are reccomended by plenty of tuners and I can save a decent amount from my local Napa.

Be sure to gap the plugs. They are supposed to be pre gapped but Ive found them to be on the large end of gap and even out of spec for the ecoboost. Gap them to.026-.028

Third just be careful when replacing and the boots are fine. Ive had no issues on my truck or cars.

[axeman_87]

okay. those NGK One step colder? Are they the Iridium plugs? never heard of one step colder

[Snox801]

Yep ngk iridium and yes one step cold helps with detonation. Its very common in st and RS world

[chefduane]

I changed mine and 90k miles (per Ford recc) and used the stock Ford OEM plug. No problems. I did not change out the CoP.

[veener79]

How hard is it to do the plugs with the 2.7?

[Xtra]

SP 534 is the exact plug that NGK calls LTR6CI-11 stock #97177. It is NGK's best plug. It's double precious metal meaning it has iridium on the electrode and the ground strap. Which gives it the 100k service life compared to the single precious metal plugs such as the Iridium IX which is also a really good plug which NGK said is good for 40-50k.

The stock LTR6CI-11 is gapped by NGK at .032" and is stock heat range. They don't offer 1 or 2 step colder in the OEM double iridium plug. The 6 designates the heat#, 7 would be 1 colder. the 11 is the gap designation.

If you want 1 step colder goto the LTR7IX-11 stock 6510. The problem is that plug is gapped by NGK at .044" and NGK recommend only gapping down a maximum of .012" or you risk weakening the weld of the ground strap. Then it could break off in the cylinder. So that means that they only recommend gapping that plug down to .032"

Anyone running the LTR7IX-11 which is a recommended part for popular 3 bar tunes and gapped at .028"-.030" are running a little less than NGK recommends for that plug.

f you want to gap down that far I'd run the stock plug but then it's not colder. Or you run the iridium IX line gapped down to a minimum of .032" and you can be colder but also have an inferior plug. But be careful when gapping down you don't go too far and have to go back up...You still over extended it in that case.

 

**** Source AJP Machine

Edited September 10, 2019 by Xtra

[veener79]

How hard is it to do the plugs with the 2.7?

 

I am wondering the same. Not too sure how bad it is reaching the back plugs.

[Xtra]

I just installed the NGK 6510 plugs in my car. I decided to gap them at .029 despite that it is not recommended to gap them that tight. It is only .003 more than NGK recommends, about the thickness of one sheet of yellow legal pad paper.

[enigma-2]

Don't you weaken the spark when you gap plugs too small?

[Xtra]

On 8/3/2018 at 8:14 PM, enigma-2 said:

Don't you weaken the spark when you gap plugs too small?

 

 

Stock gap is .032 I went tighter because I may run a 3 bar boost. At those pressures a tighter gap will give a more reliable spark.

 

EDIT:  I ended up with a 1.3 bar boost . 

Edited September 10, 2019 by Xtra

[dolsen]

It seems to me the concern he has is with you weakening the ground on the spark plug. By closing the gap tighter, you have reduced the weld strength.

 

Think of it like this, after you open your beer can, the can tab is weak at its connecting point. If you continue to bend it back and forth, past its yield point, eventually it will break off, and youll cut your lip drinking your beer.

 

The manufacturer recommends gapping no smaller than 0.032 because you are bending the ground strap past its yield point and could cause premature spark plug failure due to a bad ground strap.

[Xtra]

The manufacturer recommends gapping no smaller than 0.032 because you are bending the ground strap past its yield point and could cause premature spark plug failure due to a bad ground strap.

 

 

This is very true. I do not intend to use them for 50,000 miles, only 10 thousand and then replace them. I hope that this short service schedule will prevent any problems.

[Snox801]

I know the say .032 but seems an awful lot of aftermarket tuners and shops go tighter. Ive been at .026-.028 on all mine since 2015 when livernois did my truck and went one step colder and tighter gap. Im at 160,000 and no issues. Look at it this way what are the chances you have a strap failure on a plug. Its almost none but what you could have is pre ignition or knock with to wide of gap when tuning. So I like my chances.

[WWWPerfA_ZN0W]

Well, a lot of aftermarket tuners also blame spark blowout for issues with their tunes. Not usually the case. Now Ford did gap the plugs smaller with Gen 5 of the SHO, but it is hard to tell why they did that. Was it due to programming updates, or did they think they were running the engine too lean, or ... etc.

 

But if it works for you, great! Just be sure to use proper technique/tools as already mentioned

[dolsen]

I know the say .032 but seems an awful lot of aftermarket tuners and shops go tighter. Ive been at .026-.028 on all mine since 2015 when livernois did my truck and went one step colder and tighter gap. Im at 160,000 and no issues. Look at it this way what are the chances you have a strap failure on a plug. Its almost none but what you could have is pre ignition or knock with to wide of gap when tuning. So I like my chances.

I understand your point and I dont disagree with you.

 

With that said I dont think that gapping a spark plug to .xxx inches is going to cause a failure. Gapping a spark plug to xx% of the manufactured gap is what you would need to look for.

 

I dont know much about spark plug manufacturing but I do know a lot about manufacturing. I believe they are manufactured to a specific range (the gap range is likely different from plug to plug, manufacturer to manufacturer) and this range ultimately dictates how small of a gap is too small for wear/reliability purposes.m

The issue isnt necessarily the gap size, the issue is how far the ground strap has been stressed by gapping outside of manufacturers recommended limit.

[Xtra]

I found this and thought I would share:

 

Damage from gapping,

Some people knock the iridium welded tip off because it is extremely brittle and soft. If you knock it off you have a dead plug. If you bend it, you have a dead plug. If you make the gap too tight and you have to open it back up you can weaken the ground strap weld and or mar the ground electrode . If you mar the ground electrode it won't cause a dead plug but will cause inconsistent spark as it will be igniting off the side of the ground electrode. The channel on the bottom side of the ground electrode is raw - no plating, so when you create more raw spots on the ground electrode you are making it hard for the plug to generate a straight spark between the gap.

If the plug starts igniting anywhere BUT the channel in the ground electrode you get weak spark and can cause spark blowout.

 

And direct from NGK:

ADJUSTING THE ELECTRODE GAP

NGK does not recommend gap adjustment for precious metal spark plugs.

A variety of techniques are used to adjust electrode gaps. An appropriate method and tool should be used for gap adjustment although it has come to our attention that a variety of improper methods are used that lead to complications.

When adjusting the electrode gap, the gap may commonly be made too small, as such, the gap may need to be opened slightly. Typically some customers use a lever such as a flat screwdriver to pry open the gap. Traditional Nickel plugs have a solid piece Ø2.5mm centre electrode that may withstand such force. Precious metal spark plugs however have Ø0.6mm fine tips that are laser welded to the centre electrode. These tips are very fragile and not designed to withstand any force. As such NGK will not provide warranty for the breakage of precious metal centre electrode tips.

It is possible to adjust the electrode gap on precious metal spark plugs using an appropriate method that will not place any force on the centre electrode tip.

Edited August 6, 2018 by Xtra

[dolsen]

Interesting, I probably just tripled my knowledge on spark plugs by reading that

[Snox801]

I have read most those warnings before. I am surprised most try and tap the plug like an old school snowmobile plug. I have a threaded tool special for this that works very well that way you have no need to touch the iridium.

[WWWPerfA_ZN0W]

Nobody wants to pay for a tool that costs more than a set of plugs LOL, but it IS the correct way to do it.

[Snox801]

I got six of paying $100 for six plugs that cost me $58 now lol I have to many ecoboost and all run the same plugs and gaps so its saving my Dutch self money

[Rob0381]

A few people in this thread mentioned it, but I can’t find an answer anywhere. What has to be removed to access the back three plugs on the 2.7 EB, how difficult are they to change?

[NoDTMF]

This service now supports the edge, fairly cheap for service manual: http://www.alldatadiy.com

So looks like a bit of work to get to all of the rear plugs.

Note the gap specified is .028 -.031

Does anyone know where the .032 came from?

[1004ron]

Any pictorials or video on how to change the plugs.

 

On my wife's 3.7L Mustang the intake manifold needs to come off, but even so it's a fairly easy job.

[Special_K]

10 hours ago, 1004ron said:

Any pictorials or video on how to change the plugs.

 

On my wife's 3.7L Mustang the intake manifold needs to come off, but even so it's a fairly easy job.

 

@snmjim Should be able to help you.  but the fronts are easy as pie, its the backs that are a straight up PITA.  you have to remove the intake box, rear turbo inlet, and then use skinny hand powers to get them out.