Spark plug gapping

[tak1313]

So I was just browsing another thread that's about starting plugs with a rubber hose. I PERSONALLY just use a socket and gently turn with my hand until it starts, but it reminded me about this tool.

I don't need it, as both my Tacoma and Prius use plugs with the gap out of the box, but just curious how well something like this really works if anyone has used it. There's a video in the product pics.

https://www.amazon.com/dp/B09NVQJYPX/?tag=atomicindus08-20

 

[teagueo]

Never seen one of those before. I've always used one of these:

 

[seber]

The standard tools sold at the counter of every parts store for less than a dollar have been working just fine for at least fifty years. I see no reason to complicate the process.

 

[bwringer]

Interesting. I don't see why that tool wouldn't work, other than the fact that it only works if you always start out with a wider than needed gap. And if you crank down too hard on the knob, you'll damage the center electrode.

One of the problems with the old-skool tool is that it's easy crack the porcelain around the center electrode if you don't know what you're doing. Setting gaps is not hard, but you have to pay attention.

And yeah, the gappable spark plug is beginning to fade from memory. Other than some lawn equipment and very old vehicles, they just aren't used.

Even on vintage machinery (like my 1983 Suzuki), new plugs have always come out of the box perfectly gapped from the factory. I eyeball them for damage, but I mostly stopped bothering to check the gap long ago.

 

[tak1313]

Yeah, when I've had to gap a plug, I've only used the type @teagueo shows above.

The tool showed up on Amazon when I was searching for a magnetic spark plug socket some time ago, and I thought it was interesting for the following reasons.

1. One is less likely to "overshoot" when narrowing the gap, which would then mean having to pull the gap back, with the possibility of again overshooting the other way, etc.

2. It seems like one would have to crank down fairly firmly because to overcome the "memory" of the outer electrode so it would not then bounce back at least a little, resulting in a gap a little wide - but of course, one could compensate by using a slightly smaller feeler.

3. But then, even if you use a slightly smaller feeler to compensate, as you state, there is a high danger of damaging the center electrode or the tiny disk of iridium that is usually at the tip of the ground electrode - especially with iridium plugs. Of course, that would be less of a concern on "standard" style plugs.

3a. I THINK all cars that spec iridium also spec to NOT regap/change the gap because of this.

 

[dnschmidt]

Fine for old school copper plugs. VERY RISKY FOR new school iridium plugs. The center electrode on these are a fine as human hair. Don't mess with them.

 

[andyvh1959]

With modern high energy ignition systems gapping is less an issue than in the past. Although, vintage magneto systems can easily produce huge spark gap jumping ability. Spark plug gap is really a way to fine tune ignition timing. Ancient hit/miss engines relied on plug gap to actually set the "timing", most of them didn't even have points to adjust. My 2001 Dakota (4.7V8) had over 175,000 miles on it when I replaced a few coil packs, so I checked those plugs on the coil packs to find the ground tip had fully eroded back to nothing. I removed all the plugs to find them all the same. The "gap" had eroded to well over 0.063", when standard plug gap is around 0.030". The spark from the tip was jumping sideways to the plug body. My Dakota always started easily, idled smooth, still got the typical crappy Dakota 4.7V8 mileage at 19mpg on a good day.

So I replaced all the plugs, properly gapped, expecting to at least gain maybe a mile per gallon on the highway. Nope, not one bit of change. Started the same, idled the same, mpg the same, even after making sure all the other usuals were correct (air filter, etc). Plug gapping helps fine tune ignition timing, put it doesn't require anything more than the cheapo gap tools sold in every automotive aisle in nearly any store.

 

[Rusted Nut]

I can see how this tool will decrease gap, but how would it increase a gap? Maybe I’m missing something here. I know you shouldn’t use the ramp style gapping tool on newer plugs, to avoid damaging the electrode, but can’t see spending $$$’s on something like this.

 

[cmandp]

Yeah I do not touch modern platinum or iridium plugs with any kind of feeler gauge. I look to see if the gap seems correct by comparing to all the other plugs and install. I also only use the original OEM plug that came with the engine.

 

[rlitman]

Fine for old school copper plugs. VERY RISKY FOR new school iridium plugs. The center electrode on these are a fine as human hair. Don't mess with them.

NGK says you can test gap using the WIRE style tool shown above. Never test gap with a feeler on these, as electrode damage is likely. And if the gap is wrong, the plug is NG.

 

[pbon]

I gap down plugs for performance forced induction use, both iridium and copper. I like the new style tool though I also have the old style tool. I never open a gap for my use. Most people don’t need a tool — just buy the correct plug application for your car from a quality provider (to avoid counterfeits) and they will come reliably pre gapped.

 

[Certified Drunk]

I do everything you guys say not to do. lol
I have to gap iridium plugs all the time, otherwise I'll have spark blow out.
The problem I've ran into is counterfeit plugs.

 

[bwringer]

WTF is "spark blowout"?

And yeah, counterfeit plugs are all over scAmazon and fleaBay. You have to stick to the proven auto parts supply chain; your local auto parts store, car dealer, or RockAuto.com

 

[Certified Drunk]

Spark blowout is not really a blow out, but unable to fire in a boosted engine.

Spark Plug Selection and Spark Blowout - VAST Tuning LLC

Iridium, copper, platinum, multi-electrode, single-electrode, plutonium, space dust! The list of spark plug options at first glance can be daunting. Many manufacturers claim their spark plugs will boost performance and increase mileage. Online preachers will swear that their $20 quad iridium tip...

vasttuning.com

As for the counterfeit plugs, they have made it into the authorized dealers.
Iv'e gotten fake plugs from Summit, Rock Auto..
Sparkplugs.com is my goto place for plugs.

 

[JeepYJ]

A few questions

-How do you determine you have purchased counterfeit spark plugs?

-How often are you buying spark plugs?

-How often are you changing spark plugs?

Cars built within the last 25 years or so are usually good for a 100,000+ mile change interval and I’m sure quite a few cars go their full lifetime on the original plugs when they go to the crusher with 200,000-300,000 miles.

 

[rust in the eye]

Most plugs today are correct out of the box.
This type has served me well for decades. The wires are better than flat feelers and the hook can be used to widen the gap without touching the center electrode.