Spark Plugs with the wrong gap

[Bryf50]

I have an 04 Galant V6. Initially I ordered oem replacement NGK plugs from RockAuto. So I bring it to my mechanic friend to change the plugs and do some other maintenance when I realize they sent me the wrong plugs. So I run to Autozone where they look up my car and I pick up a set of Bosch plugs. Looking into now though I see the plugs they gave me are gapped at .044 while the oems were .032. The service manual also calls for .032 plugs. Now it wouldn't be such a pain to just swap them out but the intake manifold on the V6 covers the rear 3 plugs and its quite a pita to remove it. Is it worth worrying about? The car seems to be running fine but Googling turns up some varying answers.

 

[LTC8K6]

Why wouldn't the gap have been set correctly?

 

[EagleKeeper]

If the type of plugs can be used for different vehicles, there is no reason to expect the gap to be set correctly.

I was always told when I purchased plugs and/or a mechanic installed then, to double check the gap.

Larger gap is weaker spark. Smaller gap is not coordinated explosion.

 

[Bryf50]

I didn't mention they're Iridium as were the oem ones. From what I understand the gap on Iridium plugs comes set and shouldn't be messed with.

 

[Zenmervolt]

From what I understand the gap on Iridium plugs comes set and shouldn't be messed with.

Horsefeathers.

You can re-gap iridium plugs all day long. You do have to be careful not to damage the center electrode, but there's nothing preventing you from changing the gap by bending the ground. Just don't get ham-fisted with the feeler gauge and you're fine.

I've never bought a set of plugs where at least one didn't need re-gapping. That's just the nature of spark plugs.

ZV

 

[thelostartof]

If you are sure the gap is wrong I would spend the time and effort and re-gap them correctly.

You can put way to much strain on the ignition system and cause parts to wear out prematurely, nevermind risk of random misfires, bad mpg and overall running bad.

 

[Fritzo]

Horsefeathers.

You can re-gap iridium plugs all day long. You do have to be careful not to damage the center electrode, but there's nothing preventing you from changing the gap by bending the ground. Just don't get ham-fisted with the feeler gauge and you're fine.

I've never bought a set of plugs where at least one didn't need re-gapping. That's just the nature of spark plugs.

ZV

If they're the 4 prong electrode versions, it is very difficult to gap them. You may have gotten the wrong ones. Look up the part # on amazon and verify.

 

[Pacfanweb]

If the type of plugs can be used for different vehicles, there is no reason to expect the gap to be set correctly.

I was always told when I purchased plugs and/or a mechanic installed then, to double check the gap.

Larger gap is weaker spark. Smaller gap is not coordinated explosion.

It'd have to be a LOT larger gap to weaken the spark. A little larger, and you have a stronger spark.
These 100k mile or more plugs have huge increases in the gaps as they wear, and it has the effect of making the sparks stronger.

Only when the coil starts having trouble actually having enough energy to jump the gap does the spark get smaller.

I remember back in the early 90's, when the first Ford Explorers came out with regular Platinum plugs instead of Copper, they were rated for 60k instead of 30k. So a couple of years later, they started showing up for 60k services and we replaced them.
Then we had numerous people coming back, complaining about reduced fuel mileage. And this would be on vehicle we did everything on....fuel filters, tranny/coolant service, injector/throttle body cleans, air filters.....a vehicle you'd think would be in top working order.

We couldn't figure it out for the longest time, then our Ford district engineer told us it was the plugs.....we replaced plugs that had their gaps worn up to .080" and sometimes even bigger, with new plugs with the stock gap, which IIRC was like .052-.056".

The gap increase actually made the spark stronger, and it had more efficient combustion as a result, and slightly better mileage.

Now granted, that was with the old EEC-IV computer systems, and they weren't as adaptable as the OBD-II's are, so with modern cars there isn't much difference, but the point is, you'd have to have a HUGE gap increase to have an actual weaker spark.

 

[phucheneh]

IMO if you're gapping anything other than coppers, you're buying the wrong plugs.

I've never had to modify the gap on NGK or Denso platinum or iridium plugs. They are always spot-on out of the box. My habit anymore is just to pull all the plugs out of the packaging and hold them up to some light to double-check that the gap hasn't gotten crushed as a result of improper handling or something.

Some will argue that it's too hard to see thousandths of an inch, but if one is far enough out to really matter, it will be surprisingly apparent. I don't check with a gapper...I guess you can if it makes you feel better, but I would avoid using any pressure- use the tapered disc type, slide until you get the tiniest hint of drag, check number. If one is out, return it.

Of course, this all goes out the window with coppers...or if you buy Champion, Delco, Autolite, or one of the other various brands that I've seen come out the box looking like they were gapped by Helen Keller and/or sat on by an elephant. Delco is the worst...I've seen the cathodes in various positions that did not actually pass directly over the center electrode. Didn't appear to be damage...just REALLY poor manufacturing.

 

[Zenmervolt]

If they're the 4 prong electrode versions, it is very difficult to gap them. You may have gotten the wrong ones. Look up the part # on amazon and verify.

Fair, but no car on earth specifies those piece of shit plugs as OE. Multi-electrode spark plugs are marketing gimmicks that just aren't worth using. With the 4-electrode plugs you're shielding almost all of the spark which is just awful. I've also had problems with the damn things grounding out on the cylinder head instead of the electrodes.

IMO if you're gapping anything other than coppers, you're buying the wrong plugs.

I've never had to modify the gap on NGK or Denso platinum or iridium plugs. They are always spot-on out of the box. My habit anymore is just to pull all the plugs out of the packaging and hold them up to some light to double-check that the gap hasn't gotten crushed as a result of improper handling or something.

Completely disagree. I've had NGK platinums off by several thousandths with no obvious crushing on visual inspection. I always run a wire feeler gauge through the plugs to check the gap before use.

ZV

 

[kitatech]

Fair, but no car on earth specifies those piece of shit plugs as OE. Multi-electrode spark plugs are marketing gimmicks that just aren't worth using. With the 4-electrode plugs you're shielding almost all of the spark which is just awful. I've also had problems with the damn things grounding out on the cylinder head instead of the electrodes.



Completely disagree. I've had NGK platinums off by several thousandths with no obvious crushing on visual inspection. I always run a wire feeler gauge through the plugs to check the gap before use.

ZV

....and if NEW/UNINSTALLED plugs are indeed out-of-spec then they should be returned and replaced before installation.

 

[tortillasoup]

If the type of plugs can be used for different vehicles, there is no reason to expect the gap to be set correctly.

I was always told when I purchased plugs and/or a mechanic installed then, to double check the gap.

Larger gap is weaker spark. Smaller gap is not coordinated explosion.

Bigger gap = more efficient/complete combustion at the cost of increasing likelihood of a high RPM misfire since it's a harder/more difficult spark to make. You use a smaller gap if your car has trouble with combustion and misfires easily. I tend to stick with stock specs because if the car can't run well at stock specs then it means I need to address some issues before they get out of hand. People use smaller than stock gap if they're burning oil, the center electrode is worn and they don't want to replace the plugs, turbo'd cars I believe us smaller gaps as well, those with weak ignition systems also use smaller gaps.

 

[LTC8K6]

Q. Do I need to set the gap?
A. Generally, no. The DENSO Iridium Power plug comes pre-set with a protective sleeve over the firing end, to protect the gap from accidental alteration. DENSO Iridium Power?s ultra-efficient firing power compensates for normally recommended gap settings that are smaller than the pre-set value. In the cases of vehicle modifications (nitrous, turbo-chargers, super-chargers, high power ignition systems, etc.), some adjustments may be desired. Or, if you prefer to remain consistent with factory specifications, you may adjust. However, please be careful not to place any stress on the fine center electrode during adjustment. You could accidentally break off the very hard, and therefore brittle, tip.



Q. How do I gap Iridium plugs
A. Before attempting to gap any DENSO Iridium Power spark plug, please review the specification chart to see the factory-preset gap. In most cases your Iridium Power plugs do not need to be gapped. Even with small variations in the factory set gap the ultra-efficient firing power design will compensate for those small variations. Should you decide to re-gap your Iridium Power plug, use extreme caution as improper gapping may damage or destroy the Iridium center electrode or porcelain center. To increase the gap size: Step 1 Use needle nose pliers or spark plug gapping tool to bend the ground strap up to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN. Step 2 Re-check the gap with a calibrated gapping tool. To decrease the gap size: Step 1 Use the same method as above, however bend the ground strap down to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN. Step 2 Re-check the gap with a calibrated gapping tool. WARNING: Failure to follow these directions may permanently damage the spark plug. Note: Never use a round gapping tool to check the gap or to increase or decrease the gap setting.