indexing sparkplugs [Merged 7-8] index plug plugs spark

[romeen]

I'm not sure if this would provide any benefit given the design/shape of our combustion chambers. Has anyone tried it? If so, what difference if any did you notice?

 

[twicks69]

Indexing your spark plugs for "optimum burn direction" is not going to show you any real levels of measureable performance gains. The intake/exhaust manifold and head port design is much more important for combustion efficiency, along with all the other details....

It is more important to run good NGK spark plugs set at the same gap across all cylinders.

For example: stock performance levels up to 18psi or so NGK BPR6ES. Modified and boosting up to 22-23psi use NGK BPR7ES. Heavily modified and 28-50psi NGK BPR8ES. Add at least another stage colder for nitrous setups. Gapping at 0.028" is stock and good for most vehicles. It is not reccomended to increase the gap higher than this number unless you are running a good aftermarket ignition system, and even then it isn't nececssary.

If you have a dyno at your disposal, go ahead and see if there are any measurable performance gains by indexing your spark plugs. If not, you have better things with these cars to do to make power -- turn up the boost.

 

[Defiant]

It matters more on single-valve engines, although there you'll be lucky to see 5hp. Note that the factory standard plugs are dual-electrode.

 

[Echo5Zulu]

After researching spark plug indexing I never did read anything that mentioned the following observation/tip Im about to share. Please correct me if wrong.

Anyway I decided to index my sparkplugs last weekend since my car is down for winter installs and upgrading. (Indexing is aligning the gap to aim at the intake) I first called on indexing shims they said they were $15 a kit. Ok not bad but a little steep then he said you need a kit for each cylinder. I said forget that. He then mentioned I could just buy a bunch of spark plugs and try em all out and keep the ones that aligned right. Little crazy but true.

That got me thinking. Why not just strip different shims off old plugs I had laying around! Turned out the idea worked perfectly! Some needed thicker shims and some needed thinner. The moral of the story is my plugs are indexed, it cost me nothing, and saved me from spending $60 on $1.50 worth of shims!! What a racket. Hope this helps some of you save some cash.

 

[forcefed 95]

I have heard both good and bad about indexing spark plugs. Some ppl think it helps and other say its a waste of time. Im just curious to see what some others thing. IF you have tryed and compaired or notice any difference in doing this?

joe

 

[AK_4g63t]

I haven't done it myself but I am going to when I get my car running. I have a friend who use to race muscle cars that swears by it and says it will get you 1/2 a car length in a 1/4 mile.
-Donny

 

[DSMboostin15]

The reasoning behind indexing is the fact that the spark is directly in front of the incoming air/fuel mixture. Theory is that the mixture will travel into the spark and not have to go around the plug to ignite. Now whether this works is debatable, but a 1/2 car length sounds very suspect. I doubt that it would make that great of an impact.

 

[Mr Peepers]

This is from NGK's website:

4. Indexing

This is for racers only !!
Indexing refers to a process whereby auxiliary washers of varying thickness are placed under the spark plug's shoulder so that when the spark plug is tightened, the gap will point in the desired direction.

However, without running an engine on a dyno, it is impossible to gauge which type of indexing works best in your engine. While most engines like the spark plug's gap open to the intake valve, there are still other combinations that make more power with the gap pointed toward the exhaust valve.

In any case, engines with indexed spark plugs will typically make only a few more horsepower, typically less than 1% of total engine output. For a 500hp engine, you'd be lucky to get 5hp. While there are exceptions, the bottom line is that without a dyno, gauging success will be difficult.

http://www.ngksparkplugs.com/tech_support/spark_plugs/installation/index.asp

 

[Defiant]

The only possible negative I can dream up is perhaps a loss of some plug cooling from using more than one gasket. Perhaps.
I just can't see it helping enough to bother with, but with four cylinders, it wouldn't take long. But where's the optimum index in a dual-valve head?

 

[SpawnedX]

I am curious if anyone here has actually indexed their plugs, and if they have, do you notice a change in performance or not.

 

[99gst_racer]

It probably wouldn't ever make a difference on an a 4G63. We have a hemispherical combustion chamber with the spark plug centered between the valves. If we had a head that more resembled that of an old small-block Chevy, we could probably benefit a small amount from doing it.

 

[SpawnedX]

Thanks, I won't bother to waste my time then. That makes perfect sense too, never really thought about the fact that the intake it spraying right on the plug as is.

 

[Freerevving]

I'll probably get flamed for this

I just use DENSO iridium plugs, it's almost like indexing them (in some ways better) as the electrodes are so small

Indexing is to acheive a nice even burn... which definitely has a benefit on high HP applications.... Small electrodes achieve the same thing

I like NGK copper plugs but NOT their iridium plugs... NGK iridium center electrodes hold up fine, but the ground electrodes melt

 

[SpawnedX]

Have you used those Denso plugs prior to this recent change? If so, how do you personally feel on their performance.

 

[silver bullit]

I do, but i cant really tell you if it made a difference cause i have the but dyno.

 

[SpawnedX]

I was considering trying them over the NGK's, but I get mixed comments on them.

 

[Freerevving]

Have you used those Denso plugs prior to this recent change? If so, how do you personally feel on their performance.

I've used them (as well as many other plugs) in several cars... the "butt dyno" has shown a torque increase in every one of them... although harder to notice on the turbo 4g63. Start-ups are better with denso iridium, for a long time.. The same as a brand new set of copper NGK's

Better fuel efficiency usually creates more torque... which I believe is the case with both the iridiums and indexing. The Denso iridiums don't change for a very long time either

NGK coppers are the best copper plug, but with their iridiums, the ground electrode has massive erosion after 10k miles, sometimes sooner

 

[99gst_racer]

Let's keep this on-topic, guys. I don't want this to be another "which spark plug do you use" thread.

I do, but i cant really tell you if it made a difference cause i have the but dyno.

How did you do it? Just aim the grounding electrode at the centerline between the exhaust valves?

 

[romeen]

I indexed the plugs that are currently on the car. I really couldn't tell any difference.

How did you do it? Just aim the grounding electrode at the centerline between the exhaust valves?

Yes. I used a Sharpie and made a mark on the spark plug socket. I put the plug in the socket with the open side (opposite the grounding strap) lined up with the mark so that I could tell how the plug was oriented when installed. Then tried different plugs in different cylinders and through trial and error chose ones with the desirable orientation (center electrode unobstructed towards intake valves). Again, I didn't notice any benefit, most likely for the reasons you stated earlier.

 

[Freerevving]

How about thin washers? just one common method... but then again, not sure you would see the benefit without a dyno, as the gains are small

Most people who claim this is advantageous are running well over 500 hp and the car is race-only... It's one of those things for racing "any little edge" over the opponent... but many people claim it works

 

[Defiant]

I'll probably get flamed for this

I just use DENSO iridium plugs, it's almost like indexing them (in some ways better) as the electrodes are so small

Indexing is to acheive a nice even burn... which definitely has a benefit on high HP applications.... Small electrodes achieve the same thing

I like NGK copper plugs but NOT their iridium plugs... NGK iridium center electrodes hold up fine, but the ground electrodes melt

Please explain to me why you'd flush your money down the iridium toilet? Iridiums are for longevity, created for the marvelous modern GM shitboxes that require engine displacement for spark plug servicing.
There is no real payoff for using them in an engine where you can reach the plugs.

No, plug type -other than surface gap plugs- will not simulate indexing. Indexing is done to "gain" where the flame front starts in the combustion chamber. It's as much superstition and compulsion as it might be sound tuning.

You'll do better with NGKs in a DSM than you're doing with those NipponDenso plugs. NDs are for Toyotas.

 

[Freerevving]

Please explain to me why you'd flush your money down the iridium toilet? Iridiums are for longevity, created for the marvelous modern GM shitboxes that require engine displacement for spark plug servicing.
There is no real payoff for using them in an engine where you can reach the plugs.

No, plug type -other than surface gap plugs- will not simulate indexing. Indexing is done to "gain" where the flame front starts in the combustion chamber. It's as much superstition and compulsion as it might be sound tuning.

You'll do better with NGKs in a DSM than you're doing with those NipponDenso plugs. NDs are for Toyotas.

Denso makes a good iridium plug... the gap doesn't change every 10k miles... NGK makes a crap iridium plug... I've seen the gap change dramatically at 5k miles

I've tried many many plugs... and NGK coppers work best in ALL engines
....BUT SO DO DENSO IRIDIUMS

To say that iridiums don't do something similar to indexing would mean that indexing has nothing to do with flame quenching. The Very Reason for using iridiums is for the extremely small electrodes. They quench the flame a lot less, and burn more evenly across cylinders... which is the exact same reason you index your plugs.

On top of everything else, they heat index differently. The smaller amount of metal means that they run a tad bit cooler... But the main thing is they aren't as affected by temperature variations, for example they'll run cooler during a sudden blast onto the freeway

What's more denso (i repeat, Denso) iridium stay cleaner than the BPR6ES's... Not sure why but they do... and it's not because they're hotter because I've ran the stock heat rating on a (bumped up) 12:1 compression engine without any knock or signs of pre-ignition. Never had a problem with these plugs and still don't. They are supposed to have a stronger spark because of the fine electrodes and larger gap... and I believe it.

So smaller electrodes (similar to indexing / less flame quench), long gap life, cleaner plugs, =
You've changed your plugs 4 times and my plugs are still looking new

Believe it or not they run AT LEAST as well as the BPR6ES's and about a 1/2 step cooler

I'm not sure what makes you think they were made for cars with hard to get to plugs... that just isn't so. They were specifically designed for performance
Denso doesn't make a lot of high-quality products, but they do make one thing really well

It's rediculous that so many people can jump to the idea that "only one plug works" when so many others have had equally great results with other plugs.
I believe that most of the people having bad results with non-NGK plugs were using a platinum plug, a multi-electrode plug, or an autolite. The heat indexes are all screwed up with those plugs.

I would have never bought Denso's back when they were $15 for one plug. But after having two (in a row) bad experiences with NGK Iridium, I wondered if the Denso's would be better... and now they are affordable...

At $31 after tax for a set (check Autozone), they are hardly a waste of money... especially when start ups are as smooth as butter, and you never have to re-gap the plugs

 

[Defiant]

Denso makes a good iridium plug...

I never intimated that they didn't. I asked why you waste the money on them.

the gap doesn't change every 10k miles...

You have gaps changing? From what? By how much?

NGK makes a crap iridium plug...

Any plug's crap if you're using it in the wrong application.

I've seen the gap change dramatically at 5k miles

You should track down what's causing that. It shouldn't be happening. Then again, if I'm pulling a plug, it's only to replace it. I've never understood doing $10 worth of work on a $2 part.

I've tried many many plugs... and NGK coppers work best in ALL engines
....BUT SO DO DENSO IRIDIUMS

So.... you have more than one "best"? This could be some of the trouble. Is there another personality there I'd do better speaking with? This sounds eerily like the "more fair" expression.

To say that iridiums don't do something similar to indexing would mean that indexing has nothing to do with flame quenching.

Well, no, it's flame propagation, not quench. Quenching should be pretty-much done with by the time the spark's started the burn.

The Very Reason for using iridiums is for the extremely small electrodes.

Which isn't a good thing to be doing in a supercharged combustion chamber. Perhaps you weren't around when they found that out when Bosch Platinums were new on the market.

They quench the flame a lot less, and burn more evenly across cylinders... which is the exact same reason you index your plugs.

Or, so the old wives will claim. It really doesn't matter. You won't get five consecutive cylinder firing events to be consistent enough to show any significant difference between indexed and screwed-in-till-snug sparkplugs.

On top of everything else, they heat index differently. The smaller amount of metal means that they run a tad bit cooler...

Less metal would both have less heat retention, and less heat conductivity. The second feature is what they decided was killing-off the Bosch Platinums in turbocharged engines.

But the main thing is they aren't as affected by temperature variations, for example they'll run cooler during a sudden blast onto the freeway

I'd like some empirical data on that.

What's more denso (i repeat, Denso) iridium stay cleaner than the BPR6ES's... Not sure why but they do...

Or, so you think? I've not seen "dirty" plugs on a healthy engine since we got rid of carburetors.

and it's not because they're hotter because I've ran the stock heat rating on a (bumped up) 12:1 compression engine without any knock or signs of pre-ignition.

Holy crap, what the hell are you using for fuel to be able to get that thing to run? And better, can you shut it off?

Never had a problem with these plugs and still don't. They are supposed to have a stronger spark because of the fine electrodes and larger gap... and I believe it.

Well, reality can't trump faith.

So smaller electrodes (similar to indexing / less flame quench), long gap life, cleaner plugs, =
You've changed your plugs 4 times and my plugs are still looking new

And they'd better, for the prices you're paying. Three more changes with my nice, shiny new plugs, and your hoary old used-up plugs will be tapping your wallet again. And still deeper.

Believe it or not they run AT LEAST as well as the BPR6ES's and about a 1/2 step cooler

I'd like to know how you're measuring your combustion chamber temperatures. Or is this simply your faith speaking, again?

I'm not sure what makes you think they were made for cars with hard to get to plugs...

Because I was there when the goddamned things came out, along with the GM dogbone engine mount that had to be removed to get to them.

that just isn't so.

Apparently we have a divergence of opinion.

They were specifically designed for performance

They're for consistent performance -primarily, stable smog emissions- over long life. New car owners no longer change sparkplugs. That task usually falls to the third owner of the car.

Denso doesn't make a lot of high-quality products, but they do make one thing really well

They make every switch, relay, knob and harness for half the Japanese manufacturers, and I've lost track of what all other world makers. I'd say their quality is easily the match for Stanley, and far beyond Lucas, Jaeger and Bosch.

It's rediculous that so many people can jump to the idea that "only one plug works"

It's not an idea we've "jumped" to. It's one that has been proven to us thousands of times over.

when so many others have had equally great results with other plugs.

Check these and other DSM forums for the "great results" others have found in using non-NGK sparkplugs.

I believe that most of the people having bad results with non-NGK plugs were using a platinum plug,

Proven to be a disaster in turbocharged applications since about three months after their debut, and subsequently marketed by Bosch to not be used in turbocharged applications.

a multi-electrode plug,

The factory specified plug for the turbo DSM is the NGK EKN, dual-side-electrode plug.

or an autolite. The heat indexes are all screwed up with those plugs.

I'd like a cite for that claim. Not that anything would affect how many Autolite products I'll be buying in my lifetime.

I would have never bought Denso's back when they were $15 for one plug. But after having two (in a row) bad experiences with NGK Iridium,

Why would you have gone to iridiums in the first place? The manufacturer doesn't call for them, the users out here don't use them.

I wondered if the Denso's would be better... and now they are affordable...

At $31 after tax

Holy crap.

for a set (check Autozone), they are hardly a waste of money...

Your money must come in easier than mine does.

especially when start ups are as smooth as butter, and you never have to re-gap the plugs

"Re-gap"? Que? Oh, I guess at $7.75 a throw, you'd need to re-gap them to make up for the cost.

Hey, do what you like. It was your money. I still just can't grasp why.

You see, back on the "indexing" topic (oh yeah, there was one), it might occur to people that it's not the indexing that's making the difference. More likely it's that any mechanic who'll put in the effort to index spark plugs on a four-valve head is also more likely to be the one to not just install adjustable cam gears, but to actually degree-wheel the crank to find the optimum point in that adjustability. I've been there. I've been the thirty hand-rubbed layers of Dulux lacquer route. I've got twenty years of that crap behind me and the cars were still just cars, dying to get back to being iron oxide as soon as you'd turn your back. It's sand against the tide. Iridium plugs are just another example of it. Save your money, unless spending it is to help stave-off your other compulsions. The car's not going to give a crap. The "performance edge" you imagine you're reaping falls just a bit short of how much better a good wax job makes the car run. And I don't mean your bikini line.

 

[Freerevving]

I e.

NGK iridium ground electrodes erode very quickly (didn't I already say that?).... that's why the gap changes so quickly
This doesn't happen with the Denso's

I'm not sure what you're arguing

You say Flame Quench has nothing to do with indexing and you use the term flame propogation, which doesn't make sense since you must be referring to the same thing:
The spark occurs in the center of the cylinder no matter what...
The flame spreads across the cylinder differently because of flame quench

As to the extra metal in the cylinder, You only reiterated what I said... it stores more heat... It's a hot-spot... can't find you a reference at the moment but proof is out there

When it comes to the smaller electrodes running cooler during a "sudden blast"... I must admit I have no proof... it is merely speculation and theory... but agreed upon by many racers who use small-electrodes, or file their electrodes

Platinums suck... never enough platinum in them to help (except NGK Platinums which are too expensive... $14 plug)
The design and heat index of Bosch Platinums are especially the worst... A lot of people know this

Autolite: my mistake... THEY WORK GREAT IN CHEVY's as you like to make reference to... and apparently a lot of other cars..... but I've notice problems with erosion and idle quality in both German and Japanese cars

After reading your original argument I called a racer in both Circle Track and Drag Who's been racing for over 30 years and building engines longer.

He agreed with me on ALL my statements... EXCEPT for the Autolites
He especially agreed about the small electrodes... AND he files his electrodes for that reason. This is apparently a common practice.
I heard from him what I've heard from so many other racers and mechanics.. and what I've been telling you. I just wanted to call him to affirm what I've been telling you

I still don't see how this is a waste of money... When you're willing to use Redline oil or BG because it performs better and has longer service intervals... Same as these plugs...
sorry if I sound like an advertisement

And you're right... I can do what pleases me. Using these plugs makes sense. So I want to spend a little extra money... what business is it of yours and why are you arguing this?

AND FOR G*D'S SAKE, WHY AREN"T YOU JUST RE-GAPPING YOUR PLUGS? It takes all of 1 minute per plug.... Maybe you are the one wasting money.

As this refers to indexing:

As my racer friend, Tom, said in his own words (not exactly word for word):

"I don't bother indexing the plugs... I just file the electrodes... This does an even better job of reducing flame quench.... on Dyno tests we have seen gains between 5-10 hp, usually across the whole power band... I don't bother with iridium plugs because I get Autolites basically free, and we replace them before every race"

Holy crap, what the hell are you using for fuel to be able to get that thing to run? And better, can you shut it off?

is this proof of your limited knowledge of modern combustion engines? 93 octane (we don't have 91 in Texas)

 

[Defiant]

NGK iridium ground electrodes erode very quickly (didn't I already say that?).... that's why the gap changes so quickly
This doesn't happen with the Denso's

How often do you pull your sparkplugs to check their gap?

I'm not sure what you're arguing

I don't mean to argue anything. I'm still trying to find out why you think iridium plugs make any sense in an engine with easy access.

You say Flame Quench has nothing to do with indexing and you use the term flame propogation, which doesn't make sense since you must be referring to the same thing:
The spark occurs in the center of the cylinder no matter what...
The flame spreads across the cylinder differently because of flame quench

You're using the term "quench" in a way I'm not accustomed to seeing it. "Quenching" a fire is to put it out, not getting it to burn.

As to the extra metal in the cylinder, You only reiterated what I said... it stores more heat... It's a hot-spot... can't find you a reference at the moment but proof is out there

The porcelain shields it from becoming a hot spot. That's why it's there, and why it's there in the configuration it is. It is how a plug's heat range is differentiated.

When it comes to the smaller electrodes running cooler during a "sudden blast"... I must admit I have no proof... it is merely speculation and theory... but agreed upon by many racers who use small-electrodes, or file their electrodes

I'll keep that in mind if I ever go racing.

Platinums suck... never enough platinum in them to help (except NGK Platinums which are too expensive... $14 plug)
The design and heat index of Bosch Platinums are especially the worst... A lot of people know this

It wasn't a matter of the alloy of the center electrode; it was a matter of them shedding their side electrode in turbocharged engines.

Autolite: my mistake... THEY WORK GREAT IN CHEVY's as you like to make reference to... and apparently a lot of other cars..... but I've notice problems with erosion and idle quality in both German and Japanese cars

I'd expect Delco to make a better Chevy plug, but again, that's not within my anticipated automotive ambitions.

After reading your original argument I called a racer in both Circle Track and Drag Who's been racing for over 30 years and building engines longer.

Oh, good. More track tech.

He agreed with me on ALL my statements... EXCEPT for the Autolites
He especially agreed about the small electrodes... AND he files his electrodes for that reason. This is apparently a common practice.

Does he do this on his street engines? Does he have dynamometer results to show a difference in the return for these efforts? Can it be measured?

I heard from him what I've heard from so many other racers and mechanics.. and what I've been telling you. I just wanted to call him to affirm what I've been telling you

Thank god you did that, I guess.

I still don't see how this is a waste of money... When you're willing to use Redline oil or BG because it performs better and has longer service intervals... Same as these plugs...
sorry if I sound like an advertisement

Don't be sorry. But don't make assumptions about what I'm willing to use in my cars, either. But you are proving my postulate that obsessive owners will take extraordinary steps to make things "better". It's a good thing they do, too: Speed Channel, SEMA, and every automotive product on the center shelves are depending on you.

And you're right... I can do what pleases me.

Yes you can. As can I.

Using these plugs makes sense.

To you. Your claimed gains remain unfounded.

So I want to spend a little extra money... what business is it of yours and why are you arguing this?

Because you come in to our site and start talking up iridium plugs, of a brand not in good favor with fifteen years of DSM user's experience, as though they're better. Nothing shows they are. Costing more isn't a gauge of better use of money.

AND FOR G*D'S SAKE, WHY AREN"T YOU JUST RE-GAPPING YOUR PLUGS? It takes all of 1 minute per plug.... Maybe you are the one wasting money.

It's more effective to start with fresh. Especially when you don't bother with wasting money on them. If I replace the plugs in mine before the car's used-up, I'll take a look at them and see how horribly eroded they might be. But at over forty-thousand miles, the car's running fine and the gas mileage hasn't budged. I'm not going to work on a working machine.

As this refers to indexing:

As my racer friend, Tom, said in his own words (not exactly word for word):

"I don't bother indexing the plugs... I just file the electrodes... This does an even better job of reducing flame quench.... on Dyno tests we have seen gains between 5-10 hp, usually across the whole power band...

Or, so he thinks. Show it to me on a Test Engine with a crystal window, with no other changes made. Better yet, just pull the plugs and put them back in, and dyno it again. You'll see 5~10 horsepower difference every time you make a run.

I don't bother with iridium plugs because I get Autolites basically free, and we replace them before every race"

That's fairly telling. Maybe he's missing another five or ten or fifteen horsepower by not using Splitfires.

is this proof of your limited knowledge of modern combustion engines?

Yeah, I'm clueless about motors. I ask circle track racers when I want the real scoop. Or, I would if I were racing on circle tracks. Unfortunately, I'm stuck here in the real world, dealing with cops, traffic lights, speed limits, and SUVs that don't know what a slow lane is for.

93 octane (we don't have 91 in Texas)

That's just cheating, then.

We're of different schools. I'd bet if you didn't know your iridiums had been swapped-out, you'd never realize they were. But you can't overcome faith.