[Jeepman]

I'd be very very surprised if anyone can honestly say they can detect the difference between 2 thou, 10 thou or even 25 thou make to a plug's firing. This is kinda like an oil thread....not that there is anything wrong with that.

Gapped a tad narrow should give longer useful life. +/- .004" (0.1 mm) isn't much variation compared to the increased gap of a worn out sparkplug.

 

[Jeepman]

I guess the Autolite branded ones are the ones that fall on the floor before they leave the plant. Motorcraft branded plugs are fine. Even Fords don't like Autolites.

Dodge uses NGK plugs for certain applications. Ever notice your service manual gives you a Champion and a NGK part number? And as Pete said, for Japanese cars you are guaranteed to find Denso or NGK in them from the factory. Even BMW has ditched Bosch for NGK. The "ultimate driving machine" (😆😂🤣) decided that German engineering wasn't good enough.

Yes, my Jeep says Champion or NGK. The Mopar plugs for my Jeep were made by NGK years back, when I bought a set..

NGK and Denso are both Japanese companies, hence the strong Asian connection.

Autolite has been the official spark plug of NASCAR since April 2000. Has to be good.

 

[Jeepman]

AutoLite makes Motorcraft spark plugs for Ford. Can't be all that bad What vehicle manufacturers use NGK for OE plugs?

Lack of warranty serves two purposes
1. Increases sales maybe, helps keep the price down a little, more revenue / money for the higher ups.
2. No after sales commitments

 

[Jeepman]

Funny thing is, both Denso and NGK are my preferred plugs when OEM is not readily available. Autolite, with their lifetime warranty go in the bin every time. Replacing properly gapped Autolites with NGK or Densos is the easiest way I've found to clear misfires. And Autolite's warranty doesn't cover your fouled cats.

I have heard good reports about AutoLite, NGK and Champion. NGK has a lot of technical data on line about their spark plugs. I give them kudos for that.

I'm a thinking that you don't like spark plug warranties. You do realize that every time a company reduces the warranty on its products, their CEOs can afford better quality bologna sandwiches for lunch. Doesn't help your wallet any though, peanut butter and jam for you..

Denso has a warranty on some of its products, but not spark plugs.

https://assets.sparkplugs.com/documents/Denso_Warranty.pdf

Excluded from this warranty are products which are subject to normal wear and tear, such as filters, ignition wires, oxygen sensors, spark plugs, wiper blades, etc.

Doesn't make sense to me. Maybe they are afraid that DIYers messing around with their fine wire spark plugs will put them out of business. Maybe they are connected with NGK (i.e. Rhodium use plus one other reason )

 

[Jeepman]

I usually do a quick check on spark plugs to see if anything has happened to change the gap. I dropped one way back when. Should have heard that flat 4 backfire. Cant say that I have ever adjusted a double platinum or Iridium spark plug out of the box. They were pretty much dead on accurate. Minor adjustments just make things worse. If a tad tight, don't worry.

I doubt they are gapped by humans when packaged, all done precisely by machines with no arthritis.

 

[Jeepman]

This only makes it more complicated. Checked some vids regarding gapping. Recommended gapping tool had 0.044” and 0.045” but no 0.043”. Coin shaped gapper is not recommended.
Champion 9407 on their US site shows 0.041”. Same plug in europe has model number CCH9407 and has 1mm/0.039” gap.
Is the +/-0.004in being ok like common knowledge regarding plug gaps?

Multi use plugs I guess. It use to be simpler.

Today, from the rockauto.com site:

BOSCH: "Pre-gapped and nickel plated threads allow for quick installation without adjusting the gap or applying anti-seize."
I guess they don't want you messing around with the plugs. Warranty - 12 Months.

AutoLite: "This spark plug is pre-gapped, but may require minor adjustments with a Spark Plug Gap Tool / Feeler Gauge to match your engine's specifications. For proper engine performance, gaps should be within ±0.004" of OE-Recommended value."
Warranty - Limited Lifetime

Champion: "This spark plug is pre-gapped, but may require minor adjustments with a Spark Plug Gap Tool / Feeler Gauge to match your engine's specifications. For proper engine performance, gaps should be within ±0.004" of OE-Recommended value."
Warranty - 7 years. Even their copper has 2 years.

NGK: Contains a video on checking and gapping that shouldn't be needed except for their Ruthenium spark plugs.
"This spark plug is pre-gapped, but may require minor adjustments with a Spark Plug Gap Tool / Feeler Gauge to match your engine's specifications. For proper engine performance, gaps should be within ±0.004" of OE-Recommended value."
That's stated for their Ruthenium spark plugs that come pre-gapped at 0.032".
Warranty - 60 whole days, imagine that. If no warranty claims, one would think a limited lifetime warranty or at least 7 years or 3000 to 4000 engine hours would be a no brainer.

Denso: Iridium with Rhodium Center Electrode, Pre-Set Gap: 0.035" No re-gapping required per their video. No warranty on these plugs. Whoa! They aren't standing behind their product for fear of something.

The +/-0.004" seems to be common knowledge regarding plug gaps.

Some manufacturers didn't want Customers messing with the pre-set gaps because Iridium spark plugs are somewhat delicate, with their fine wire, and there's a high possibility they will be tampered with in the process. Manufacturers seem to have relaxed that lately, for some reason. Multi use?

Back in February Champion 9407 were OE pre-gapped at 0.043 per rockauto.com back then. Go figure.

The 0.041" pre-set gap today on the Champion 9407 should be fine, plus it will widen over time. Maybe that's why the warranty for Champion Iridium spark plugs is 7 years (not 60 days ). Even 1 mm gap (0.039" - 0.040") should work.

SIDE NOTE:

Do not adjust gap for factory power. Adjust plug gap from factory specification (.044") approximately .004" less for every 50 bhp added. For example: an application adding 150 bhp would require a .032" gap (.044" - .012").

NGK Spark Plugs

<p>NGK is an original equipment manufacture for the NSX spark plugs. ScienceofSpeed offers the same spark plug with out the dealer premium price. The factory spark plug for the standard NSX is the Laser Platinum No. 6. Using the incorrect spark plug

www.scienceofspeed.com

If you boost up your power, lessen the gap.

 

[Jeepman]

All plugs should be gapped, even the ones that claim to be pregapped. Champion is OEM, but many of us prefer NGK. Jeepman likes pointing out their short warranty period, but I've never seen one fail early so it's a bit irrelevant.

Why they made the decision to trash their reasonably good warranty isn't irrelevant. Did they explain why to their Customers? They need to know that information and backing product matters. Compare their warranty to any other spark plug manufacturer. NGK gets a D-.

Ajax Storm Doors has a better warranty than that. Just sayin.

No failures you say? From Post #8

In Our Experience
For NGK warranty purposes, we have to ship all damaged spark plugs back to NGK UK so that they can be officially examined and documented. As of now, it turns out 100% of the spark plugs in the last 5 years that were returned due to thread breakage were the result of customers using thread compound, or simply over tightening them. The NGK warranty reports are always compiled with detailed photographs pinpointing the exact reasons for failure, even to the very smallest of details such as hex swelling and magnified photos are taken and recorded.

 

[Jeepman]

Jumping back into the thread with a spark plug related question. The OEM plugs are Champions but they’re 0.044” instead of 0.043”. Does that mean they the have to be gapped first? Safer bet is to go with OEM aka Mopar?

Looking at rockauto.com, the OE gap is stated differently per plug
Champion 9407: 0.041 vs 0.043 OE
NGK: 0.044 vs 0.044 OE
AutoLite: 0.040 (1 mm) same as what the Haynes Manual says vs 0.040 OE.
Denso: 0.035 (whoa) vs ? OE
Bosch: 0.040 (1 mm) same as what the Haynes Manual says vs ? OE
PartAvatar.ca says 0.044 as OE for Champion 9407
They can't make up their minds as to what the OE specs are.

Per rockauto.com the Champion 9407 spark plug is gapped at 0.041 with this stipulation:

This spark plug is pre-gapped, but may require minor adjustments with a Spark Plug Gap Tool / Feeler Gauge to match your engine's specifications. For proper engine performance, gaps should be within ±0.004" of OE-Recommended value.

Not to worry, a little closer gap means the spark plug will maintain its closeness to OE gap longer.

 

[Jeepman]

I have gone through the nightmare of broken spark plugs because they were rusted into the heads. I HIGHLY recommend using anti-seize compound.....

Steel spark plugs in aluminum heads?

Over torquing can cause that.

The "trivalent plating" is an anti-seize, of a different type, that facilitates removal plus provides protection against moisture. Besides, robots and DIYers can mess up the application of anti-seize paste. Can't fire a robot.

On second thought, what does NGK know about spark plugs anyway. They only need to last for 60 days.

 

[Jeepman]

I relayed that story, not to try to impress y’all with my roadwheel installation prowess, as an example that things can be torqued, at least close enough, without using a torque wrench, the trick is knowing when it is really critical. Every fastener has a torque value, for example a 3/8”x16 grade five bolt has a torque around 39 ftlbs, any looser and it will most likely come loose and any tighter it will damage the threads snd loose it’s strength and possibly break. Now, is there a problem if it gets torqued to 38 or 40 ftlbs? I would highly doubt it would matter on your car but it will on a NASA rocket. One last question, when was the last time your torque wrench was properly checked for calibration?

When I made the comment about the guy in the video not using a torque wrench I was joking. Most mechanics have a feel for torque and it was just a quick video.
Sent from my iPhone using Tapatalk

I think wheels on public transportation vehicles have to be pretty much tightened using a torque wrench here. Two grunts and a whistle don't make the grade legally.

Many a time I have seen a Mechanic (yes an experienced Mechanic even), tighten lug nuts, using an impact wrench, and then check them with a torque wrench set at 100 ft.lb. The only thing done right in the process was setting the torque wrench at 100 ft. lb. Didn't use a star pattern either.

Once, when I went to redo nuts, things were tight, very tight actually. Eventually a 3/8" adapter, I was using, twisted off. Those adapters are good for 150+ ft.lb. normally. One of those Mechanics, I mentioned above, originally did the job.

.

 

[Jeepman]

1/12th is easy. Imagine you have a clock and you turn about one hour.

I'm digital.

 

[Jeepman]

I have been using this method for years now, works really well and the amount you need to turn after making contact doesn’t need to change when using anti-seize vs dry. But if you use a torque wrench you need to reduce the torque by about 20%.

"1/2-2/3 turn on plugs with a gasket. 1/12-1/8 turn on plugs with a tapered seat."

That 1/12 turn must be a little difficult to measure. Would that be about 5/16 of a grunt?

 

[Jeepman]

And he did not even need a torque wrench.


Sent from my iPhone using Tapatalk

That was surprising but then again, spark plug manufacturers have charts for "turn of the wrench" tightening of spark plugs.

Use a torque wrench to tighten spark plugs following manufacturer’s recommendations, or refer to the torque chart in the Autolite Spark Plug Catalog if you don’t have a torque wrench.

https://www.autolite.com/docs/default-source/product-documents/spark-plug-installation.pdf

From: NGK.com: NGK Plug Torque Settings

With a Torque Wrench:
To find NGK's recommended torque setting, please enter the spark plug number in the search box. While viewing the part detail page, click on the "specs" tab. If a recommendation has been made, it will appear under the "Specifications" heading.

Without a Torque Wrench:

If a torque wrench is unavailable, finger tighten the spark plug, then use a plug wrench to tighten. 1/2-2/3 turn on plugs with a gasket. 1/12-1/8 turn on plugs with a tapered seat.

 

[Jeepman]

Autolite Video:

I missed the application of anti-seize in the video.

As I understand it:

Plated spark plugs = no anti-seize unless reused (plating compromised). Plated plugs have a shiny finish on the threads

Unplated spark plugs = anti-seize. Unplated plated plugs have a raw, non shiny finish on the threads. Not likely for aluminum heads though. Aluminum heads get the special plated treatment.

Anti-seize, motor oil, maybe even maple syrup have been used on spark plugs for years without concern about conductivity. I don't believe there is a concern today either.

 

[Jeepman]

Just as I thought, the manual has no mention of it, so it is not used. 14ft/lbs that's it.

There's some that don't want to acknowledge that.

I don't even use anti-seize on my lawnmowers and snowblower.

 

[Jeepman]

Interesting article here re anti-seize (copper for high heat):

How to Change Your Spark Plugs & Why You Shouldn't Use Copper Grease

Spark Plug threads - To grease or not to grease, that is the big question. Click here for the answer and the common copper grease myth busted.

www.driven2automotive.com

In Our Experience
For NGK warranty purposes, we have to ship all damaged spark plugs back to NGK UK so that they can be officially examined and documented. As of now, it turns out 100% of the spark plugs in the last 5 years that were returned due to thread breakage were the result of customers using thread compound, or simply over tightening them. The NGK warranty reports are always compiled with detailed photographs pinpointing the exact reasons for failure, even to the very smallest of details such as hex swelling and magnified photos are taken and recorded.

But I Know a Mechanic Who Always Uses it on Spark Plugs?
Don't we all.

If your mechanic uses copper grease on spark plug threads well as torquing them down, then be warned! NGK is adamant this procedure should be avoided on all costs. We must remember that the spark plug manufacturers are the most experienced out of all of us, with millions of pounds spent on R&D and hundreds of qualified mechanics testing them day in, day out.

Copper is the higher heat anti-seize. Case closed on using anti-seize, don't you think?

I have about 2750 engine hours on the OE spark plugs in my 2016 DGC now. They say Iridium are good for 3000 to 4000 engine hours depending on quality of gasoline used. I run about 150 to 160 engine hours per oil change. So, they are good for another oil change or two.

 

[Jeepman]

What does the official service manual say? In Haynes manual it recommends the usage of anti-seize.

For many spark plug installations, I use to use a drop of motor oil on the threads. Worked for me, but I don't no more. Spark plugs are different these days, for our vans they come plated with a "miracle product" already in place on the plugs making a regular application of anti-seize redundant and actually a bit dangerous.

This silver or chrome-colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal.

Regardless of what anybody, or any Vehicle Manual says, spark plugs come with a torque spec and application instructions form the spark plug manufacturer itself as well as a warranty by non other than the spark plug manufacturer, not Haynes, not Chrysler, not by whoever says to use anti-seize because they have always done so.

Haynes says "it's a good idea to lightly coat the threads of the spark plugs with an anti-seize compound to ensure the spark plugs do not seize in the aluminum cylinder head". They say this without any reference to a plating already in place to do the same thing and better. Looks like they need to update their Manual.

It's funny, front wheel bearing hub assemblies commonly come with instructions saying "do not use an impact wrench for tightening". But watch a Mechanic and he/she is using an impact wrench for tightening, because they have always done it that way, plus to rush the job.

Now I know why NGK spark plugs recently moved to a measly 60 day warranty, Installers don't pay attention to their installation instructions. .

Since back about 2004 I haven't used anti-seize for initial installation of spark plugs. They go in dry and work just fine. Getting them back out hasn't been a problem either, especially when I use an impact wrench.

Note: The installation instructions for Champion spark plugs don't mention applying anti-seize.

 

[Jeepman]

Spark plugs for aluminum heads have a trivalent, or similar, plating on them to act as anti-seize, likely to facilitate installation by robots or robotic DIYers.

NGK likely knows more about spark plugs than any member here or any service manual for that matter. They make the plugs and have been doing so for a couple years now.

Here's what NGK says: 5 Things You Should Know About Spark Plugs - NGK Spark Plugs

5 THINGS YOU SHOULD KNOW ABOUT SPARK PLUGS

1. Anti-seize
NGK spark plugs feature trivalent plating. This silver or chrome-colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal. NGK spark plugs are installed at the factory dry, without lubrication or anti-seize.
Anti-seize can act as a lubricant, altering torque values up to 20 percent, increasing the risk of spark plug thread breakage and/or metal shell stretch. Thread breakage can sometimes involve removing the cylinder head for repair. Metal shell stretch changes the heat rating of the spark plug and can result in serious engine damage caused by pre-ignition. Do not use anti-seize or lubricant on NGK spark plugs. It is completely unnecessary and can be detrimental.

Other companies, like Champion, say something similar, their coating will have a different name.

The question has been asked before:

So, what is the final word on using anti seize on...

I am about to do my first changeout of the factory plugs and want to know from some of you experts what is the deal on anti seize. I asked a friend who rebuilds racecar engines professionally and got a long discussion about the relative value of different compounds, including an interesting...

www.chryslerminivan.net

The coating is a one time use as I understand it. If reusing spark plugs then anti-seize is used.