So I was about to complete my Summit order last night when I stopped because I started to think about my spark plug options...

No Earth shattering stuff here, but we did just replace the plugs on my wife's 2017 Jeep Grand Cherokee Trailhawk (3.6L V6) and whatever was the OEM stuff got replaced with NGK 7751 plugs (Laser Iridium, NGK Part# ILZKR7B11, Hex Size = 5/8", Heat Range = 7, Gap Size = 0.044", Thread Diameter = 12.00mm).

The Jeep has 150K KMs, so nearly 100K Ms, and if there was one thing I was always unhappy about is that at about 30K KMs the motor started to run a little rough. Nothing major, just that it would not have that smooth idle it originally had. Several dealership visits later netted us nothing, and well, since not many other options presented themselves and my frustration with Mopar was growing exponentially each time we visisted, well we just gave up and ran along with it.

Now after the plug change the motor is butter smooth...I kid you not! This could be a bit of a "mental horsepower" thing also, but I'd swear the engine pulls stronger as well. Hard to quantify though.

OK, so back to the Mopar hotrodding thing we got here: I've been running the NGK V-power plugs in my small block for years now (BKR6E-11). Each time I do any maintenance on the ride they look pretty clean, no complaints. But the tech moves on. NGK has had the Iridium line for a while and now has the new Ruthenium plug line with multiple ground electrode options.

Here are a few specific examples:

1) current plug - BKR6E-11


2) Iridium IX - BKR6EIX-11


3) Ruthenium HX - FR6BHX-S


4) Ruthernium HX -


The science behind it, as NGK explains, is that the finer tip and the alternative ground electrode shapes help with preventing the quenching of the starting flame front immediately after the ignition happens. This makes sense to me. Further on they claim other benefits such as less fouling, almost no wear (different materials), etc.

Therefore, given that I'll be finishing up my W2 stroker over the winter I figured why not give this thing a shot?

I'm curious if anyone has tried any of the newer tech plugs?

Thanks!

Lot of the spark plug designs are driven by the EPA standard that an engine has to run and no produce excessive emissions for 100,000 miles, so they have to last a really long time. The other thing to consider is what type of ignition system the vehicle has and the design of the plugs to work with that style ignition. The more energy it takes to Ionize the gap at the plug the more stress there is on the ignition coil. One reason why most modern engines have one coil per cylinder. I have seen lots of ignition coils burnt and replaced when the root cause of the problem was a spark plug worn out.

this will sound really stupid, but how does/should one gap the new style plugs with the super fine tips ?
i have several plug gapping tools in the box, different styles purchased over the years, but other than using feeler gauges and very carefully bending the side electrode, those super fine tips with the welded on "super metal" make me pretty nervous when it comes to gapping a plug.
i'm just afraid the gapping tool will chip, or otherwise damage the tip material.
i know the material holds up to ignition arcs and high flame temperatures, but sometimes i have been known to break an anvil or two.

You may have, and not know it, problems with the spark plug wires, coil wire, and not the plugs
I have had them wear out on one of my old bracket motors using the MSD 7 and 7AL2 race boxes, the carbon coating on the plug wires center conductor at the distributor cap burns off and will start missing a tiny bit in high gear about the 1000 clocks in the 1/4 mile . Cut the ends off and reterminate them and your good to go for some more racing

I pulled the Iridiums out of my newer stuff and put copper equivalents in after wondering about this stuff my self. My results seem to agree with what others have found on other forums..

They all ran noticeably better, Especially my little turbocharger hooptie.

Copper is a better conductor of electricity AFAIK.

My conclusion is the Platinum, Double Platinum, Iridium plugs provided progressively longer replacement intervals. Period.

Street car, beater, driver, which is a PIA to change plugs, the longer life stuff is probably the way to go if you don't want to change plugs..

Performance, race, use the copper or a race plug. And figure on replacing it once in a while.

I had a conversation with a tech guy (not a salesman) from one of the big gauge manufacturers years ago when they still had people like that on the payroll, about RFI.

He suggested, and I have followed his advice with good results, that plug wires are consumables, and should be replaced yearly if you make any number of passes. Coil wire every 6 months. Especially with the new, high energy ignitions and coils.

And some of the performance was most likely due to the fact that it takes less KV to fire the old style plugs. If you ever find a good one the old spark plug cleaners that had a window to check the plugs under a load with air pressure really tell the tale on spark plugs.

...Interesting...OK, but even the NGK Iridium or Ruthenium plugs are still 98% (or so they say) copper core, while it is ONLY the end of either electrode that uses a different material.


You do bring up an excellent point: the longevity of the plug. I am not surprised at all that OEMs have been pushing this forward...heck, who ever thought that a spark plug replacement would require an intake monifold R&R? Sure...I had to do that on my V6 Mazda6 once, but yeah, only one time, and that was well after the 150K mile marker, and I wouldn't want to do that job again.

Alright...thanks for the feedback everyone!

I'm still on the fence regarding this.

It would seem that the Ruthenium HX w/ exposed thin wire grounded electrode design offers a potential improvement to the flame-front travel. I cannot imagine that this would be a bad thing in any application either.

My ignition system today is a tranditional MP Chrome ECU + Yellow Coil combo, plenty of hot spark on my current NGKs which are gapped at 0.045". Although, I do have the MP (part# P4876729) labeled MSD box, which I believe is the 6ALN actually, that I was thinking of trying out springtime.

Anyways, I am thinking that whatever difference these make, may not actualy be noticable given my application, that being the regular "weekend warrior" type of a ride.

still no answer to the "stupid old man question of the day" about gapping the new type plugs and not screwing up the tiny tip elements ?
i try not to sound idiotic, but i try to learn new methods of doing things when possible.

All the racing plugs I use are V gap manufacture says use them out of the box. All the new style plugs With precious metal electrodes I use them also out of the box. A good racing ignition as well as newer OEM ignition systems will jump almost any gap. Gapping plugs is mainly for older style plugs in older style engines, so the old-style gapping tools still work. Back in the day we used to close gaps a little to make them run better. On new stuff it just doesn't matter. I taught at an automotive technical college we had two 350 horse SBC as mule motors. After a discussion in class, I had students index the plugs and change gaps we ran about 25 pulls that week, answer was indexing plugs and changing gaps made little to no difference.

Actually, I felt like you had already answered that in your very post by saying that adjusting by bending at the side of the ground electrode was the way...at least that's what I figured I would do if I end up trying that style of plug.

...besides, you know what they say: the only stupid questions are the ones that haven't been asked!

I don't know about the V6's, but I think Ma calls for the plugs to be replaced on the 5.7's at 35K or so miles. I think I changed the plugs in our 3.5, 2004 Intrepid at 195K miles LOL.

https://youtu.be/X31bCPiwaIk

Kevin

sometimes, i amaze myself............
i will have to make sure i have a good pair of cheaters on, and take care when measuring the gap. it looks like those tiny tips are way stronger than i give them credit for being.
thanks to all that put up with my rambling.

Dynos are just that. One type car (mopar) that I play with and others in the group have noticed a good improvement in some ares that copper provide vs others. Enough to not mind the needed change if only after 20k miles use.

I put the NGK Ruthenium plugs like in #4 in the wifes Kia last year because they were slightly less expensive than the Iridium plugs. I can't tell much difference in her car, I think it idled a bit better, but that is comparing the newly installed plugs to ones with 60,000 miles on them?
From what I could find out from some google searches, the Ruthenium plugs don't last as long as the Iridium plugs, but are supposed to have "high ignitability"?
The claim is they are supposed to get better fuel mileage?
Some info from google search:
https://carphrases.com/ruthenium-vs-iridium-spark-plugs/
https://vehiclefreak.com/ruthenium-vs-iridium-whats-the-difference/

I would use the hook, hole or whatever your adjuster tool has to bend the side strap as needed. Use the gapper to only check the gap, gently. Avoid the temptation to used the gapper as a wedge between the center electrode and the side strap to open it up.

I always verify gaps. Sometimes they need to be touched up. You have no idea how those plugs may have been handled, dropped on the floor, etc. before you got them.

Its possible to get away with non stock spark plugs in some instances.

But I can tell you from unpleasant previous experience - When a vehicle comes in for a misfire. If it has non stock spark plugs (even if they are iridium, platnum, etc just not the OE exact plug) The very first thing we do is put factory plugs back in. Many many times incorrect plugs are the cause.