gapping platinum spark plugs

[websun]

Hello, having a question on gapping spark plugs, platinum in this case. I've got a set of NGK PFR5J-11 which theoretically are factory gapped to 1.1mm and my service manual says 1.1mm so should match.
However I've found to be alot less than that, and I have doubts all six are wrong.
My confusion is if that gap supposed to include the what appears to be the ground electrode platinum part which sticks out a bit?

Thanks,
Paul

 

[AutoMechanic]

Are you referring to the little dimple like pin under the curved part? If so yes that’s included.

 

[AutoMechanic]

Yes you need to put the gauge between that part and the bottom there.

 

[websun]

I also have a set of denso which again are nowhere near 1.1mm brand new out of the box. And denso says do not gap platinum or tt ones... especially since they are matching oem specs already.

 

[doitmyself]

Your picture is incorrect. The gap is measured between the center electrode and the platinum "puck" on the ground electrode.

Also be aware and study the literature about fake counterfeit plugs on the market today.

 

[websun]

Ah yes sorry I was only pointing out that pin, not measuring that way.
I will check if ones I have are fakes... it's possible.

 

[AutoMechanic]

I also have a set of denso which again are nowhere near 1.1mm brand new out of the box. And denso says do not gap platinum or tt ones... especially since they are matching oem specs already.

They should be in spec if they had the plastic protector on them at the end in the box.

 

[websun]

these are 1.1mm now.
They were new,had plastic protectors and checked them don't appear to be fake. I still had to adjust almost all of them which confuses me...

 

[Malo83]

ALWAYS check the gap on new plugs.

 

[AutoMechanic]

Yeah I always check usually mine are right on it. It’s a good thing you checked too. And if you bought them from a parts place they likely aren’t fakes

 

[websun]

ALWAYS check the gap on new plugs.

That is what I am doing, just being confused why the gap is not correct.
I was thinking I might be doing something wrong.

Another question on topic, do ik iridium tt have same or greater lifetime than platinum? Few years ago they were performance oriented not lifetime.
Quite a job to change plugs on montero sport 3.0 so I want to do it as infrequent as possible.

 

[AutoMechanic]

That is what I am doing, just being confused why the gap is not correct.
I was thinking I might be doing something wrong.

Another question on topic, do ik iridium tt have same or greater lifetime than platinum? Few years ago they were performance oriented not lifetime.
Quite a job to change plugs on montero sport 3.0 so I want to do it as infrequent as possible.

Generally the iridium are top of the line with platinum just below them.

 

[Dave9]

Another question on topic, do ik iridium tt have same or greater lifetime than platinum? Few years ago they were performance oriented not lifetime.

There are more variables. Having the ground needle tip which reduces the ground wear area, they should wear faster than an iridium with a ground puck would, and faster than a platinum with a center electrode puck, but less lifespan disparity compared to a dbl platinum with a center electrode needle (AKA fine wire) and ground puck.

Nothing is a lifetime plug, for best results some engines need a change at 80K mi or lower, especially with a waste spark ignition system but your 3.0L (6B31?) does not appear to use waste spark.

 

[bbhero]

My car went 103,000 miles on OEM plugs. Then I went 136,000 miles on long life Denso iridium long life plugs. Car ran just fine even with 130,000+ miles on those Denso iridium long life plugs.

 

[slacktide_bitog]

Where did you buy them?

 

[atikovi]

just being confused why the gap is not correct.

A specific spark plug may be specified for dozens of applications with many different gaps. The manufacturer isn't going to make 10 different plugs of the same identical specs with gaps between 0.035 to 0.045. They will make them with an 0.040 gap and have the end used set it if their car's spec is larger or smaller than 0.040.

 

[UG_Passat]

That is what I am doing, just being confused why the gap is not correct.
I was thinking I might be doing something wrong.

Another question on topic, do ik iridium tt have same or greater lifetime than platinum? Few years ago they were performance oriented not lifetime.
Quite a job to change plugs on montero sport 3.0 so I want to do it as infrequent as possible.

They were performance when they don't have a platinum wear disc on the ground electrode, and usually have something like a tapered ground electrode to reduce quenching effects, and Denso has their "U-groove" to help with the flame kernel proprogation.

TT's are a combination of both longevity due to the platinum cylinder on the ground electrode and performance since the twin tip reduces quenching effects.

But the smaller diameter iridium tip (.4mm diameter) compared to platinum tip (1.1mm diameter) reduces the voltage requirement for the spark and improves ignitability.

 

[DGXR]

If you need to re-gap them, bend the ground electrode only and do it carefully.

Do not touch the platinum tips with anything but the feeler gauge.