spark plug gap tolerance

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the gap spec on my camry is 1.1mm. the standard copper plugs, good for 30k miles come int he box gapped at 1.0mm. I don't want to regap them from the factory. Ok to install with the 1.0mm gap?
 

crinkles

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i might add that the NGK plug that i have has an "-11" at the end of the part no, but i measured it with a feeler and it is 1.0mm not 1.1mm....
 
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Well, the old school of thought was that it was better to gap the plug a tiny bit less than what was called for, the idea being if the gap was too wide the coil would have to work harder to make the spark jump the wider gap. I'd leave them at 1.0 and use them, can't see anything detrimental about doing that.
 
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 Originally Posted By: hate2work
Well, the old school of thought was that it was better to gap the plug a tiny bit less than what was called for, the idea being if the gap was too wide the coil would have to work harder to make the spark jump the wider gap. I'd leave them at 1.0 and use them, can't see anything detrimental about doing that.
I second that. As they wear they will wear in to the proper gap. Install them and use a torque wrench!
 
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It is MUCH MORE important that all of the spark plugs be of the EXACT same gap - as each other- this is much more important than the actual gap itself. check them very carefully with the wire gap gauge - i almost always spend about 1/2 hour on a set of 4 plugs before i'm satisfied.
 
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pbm

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I would install them as they come out of the box. I always prefer the gap being on the tight side since it will open up a bit with wear. PS: Residential property is a good investment....I wish I owned some.
 
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Check the gaps when taking them out of the box if they are crushed from being shipped.They move around in the box when being shipped by truck.I have seen plugs out of a Jeep already brand new,would not start and the gaps was not checked.The gaps were crushed and the guy from another used car dealer said not to check them because it was a waste of time
 
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I would recommend re-gapping your plugs to spec. That's what the engineers thought was best for that plug and that engine. Closing the gap was a bandaid approach to weak ignition systems of the past. Today it just decreases the size of the spark which can promote a lean misfire in a pollution-controlled engine. Your gap isn't going to "open up" over night. I've found that it takes about 20K miles on most modern engines to see any gap erosion in a properly maintained, stock engine. (I change plugs frequently from "hot" street plugs to "cold" competition plugs; however, they both use the same gap.) Make sure that your feeler gauge is not worn. Try another feeler gauge preferably of a different construction (wire vs. flat). If you get different readings, buy a new gauge for your plugs. Good Luck!
 
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 Originally Posted By: MrBeachcomber
I would recommend re-gapping your plugs to spec. That's what the engineers thought was best for that plug and that engine. Closing the gap was a bandaid approach to weak ignition systems of the past. Today it just decreases the size of the spark which can promote a lean misfire in a pollution-controlled engine. Your gap isn't going to "open up" over night. I've found that it takes about 20K miles on most modern engines to see any gap erosion in a properly maintained, stock engine. (I change plugs frequently from "hot" street plugs to "cold" competition plugs; however, they both use the same gap.) Make sure that your feeler gauge is not worn. Try another feeler gauge preferably of a different construction (wire vs. flat). If you get different readings, buy a new gauge for your plugs. Good Luck!
Good advise. I never trust the out of the box gap, aside from them being banged around from shipping etc, it is very easy for a store clerk to drop the box and mess up the gap. After working in an auto parts store and doing deliveries while going to college, I can tell you, don't trust the out of the box gap!
 
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A feeler gauge is not recomended for checking spark plug gap. Some plugs have a slight radius on the ground electrode. I think you will find the plugs are gaped at 1.1mm if you use a quality wire gage. 0.10mm = 0.0039369 inches which is not enough to be concerned about.
 
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Sure, you can just screw them in. It is best to check them and set them, though. Best plug performance comes with the widest gap that will never misfire. That .004"extra allows better in and out flow of gas, in addition to a bigger and hotter spark. Are they double platinum tips? BEing a copper plug usually means the core is copper for heat dissipation. It is rarely on the tips. Precious metal tipped plugs wear slowly.
 
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Run them at spec. A known engine builder who works on my type of car recommends running gap at .6, instead of the .55 factory spec. This car has COP ignition, so there is some extra capacity to handle the larger gap. Dyno's show around a 3-4hp increase with the use of the larger gap on a basic copper core plug. Thats Different cars and different ignitions, but the factory specced 1.1m for a reason...
 
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 Originally Posted By: mechtech2
Sure, you can just screw them in. It is best to check them and set them, though. Best plug performance comes with the widest gap that will never misfire. That .004"extra allows better in and out flow of gas, in addition to a bigger and hotter spark. Are they double platinum tips? BEing a copper plug usually means the core is copper for heat dissipation. It is rarely on the tips. Precious metal tipped plugs wear slowly.
Even a double platinum is likely to have a copper core, as well as a resistor. My understanding is that most standard plugs use some sort of alloy material that includes nickel and copper for the exposed portion of the center electrode. The ground electrode seems to always be nickel plated. http://www.densoproducts.com/product.asp?productCategoryID=1 In my experience, spark plugs tolerances are usually something like 1.0-1.1 mm. There's almost always an allowed 0.1 mm range in most specs I've seen. I'm not sure exactly how the gap is measured with some of the proprietary standard plugs on the market. NGK V-Power makes things a bit interesting. However - Denso's U-Groove can make things even more interesting when the ground electrode is uneven. It's a little bit further in the groove, although I suppose it's supposed to be measured from the closest point between the two electrodes.
 
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Run at spec. It's a service replacement spec just like minimum reassembly thicknesses for brake rotors being thicker than the discard thickness. They count on the gap opening up and can handle that gap. Many threads on people finding plugs at .080 or wider still running fine. My 96 saturn had a service campaign to get a new underhood sticker demoting it from .060 to .040 gap for some reason that made sense to them.
 

crinkles

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was fiddling around with my feeler guage last night and best i could get was 1.05mm in between the tip and electrode. i reckont hat is close enough! thanks for all the replies. my camry has a 30,000 mile change interval on the standard p;ugs (no iridium on aussie model)
 
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 Originally Posted By: Captain_Klink
It is MUCH MORE important that all of the spark plugs be of the EXACT same gap - as each other- this is much more important than the actual gap itself. check them very carefully with the wire gap gauge - i almost always spend about 1/2 hour on a set of 4 plugs before i'm satisfied.
Can you explain this? I know large gaps put more load (and therefore more heat) on ignition electronics and shorten their lifespan.
 
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The current flow through a spark plug is by DEMAND. It changes. A wide gap should not wear faster. At least it cold not be measured. I like to file the ground electrode back and radiused around the plat tip. Better in and out flow. Gets rid of useless square edges.
 
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think about this for a sec: you are talking about 1/10 of a mm difference! you can't tell me that with all the variables involved that there would be any appreciable difference at all. there is no way that a wire guage will be accurate to within .1mm. now, like eljefino said about saturn, yes, for one year (1996?) they went to .060 gap, then went back to .040 and back spec'd that year. they just found that .040 worked better. FWIW, I remember reading about an old drag racers trick was to cut off the electrode completely; it created a huge spark and was good for one 1/4mi run @ a time.
 
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 Originally Posted By: hinterlander
 Originally Posted By: Captain_Klink
It is MUCH MORE important that all of the spark plugs be of the EXACT same gap - as each other- this is much more important than the actual gap itself. check them very carefully with the wire gap gauge - i almost always spend about 1/2 hour on a set of 4 plugs before i'm satisfied.
Can you explain this? I know large gaps put more load (and therefore more heat) on ignition electronics and shorten their lifespan.
Over the life of the plug the gap increase way more than that. If this is so important we would be changing plug and regapping them every oil change or so. That's clearly not the case other than the feel good factor. Unless of course if the life of the plugs you install are different by, say 30k miles apart, then that would cause some balance issues that may feel like engine misfires.
 
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