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Old 04-13-2004, 08:06 PM   #1
lunatic987
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SP Gap and problems it can cause

What kind of problems can be caused by having a spark plug gap that is a full .01 inches above spec?
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Old 04-13-2004, 08:15 PM   #2
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Slight power loss. Don't let your average saturday redneck tell you gapping your plugs more is better. Trust me, when cars are engineered they spend a lot of time getting the specs on the gaps right.
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Old 04-13-2004, 11:08 PM   #3
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I saw a plug come out of a car that the gap had increased by that much and was wondering what problems that keeping that in the car would/could cause.
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Old 04-14-2004, 12:02 AM   #4
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A bigger gap than specs call for cools down your spark which inturn doesn't ignite your fuel as well causing a power loss. .01 is not much of a difference though.

Quote:
I saw a plug come out of a car that the gap had increased by that much



Just one plug had that .01 bigger gap out of all of them? That's kinda weird
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Old 04-14-2004, 02:12 AM   #5
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actually I think the one plug was actually more of .011

2 other plugs were .005 different and the 4th was .003


nice wide range. the car was also idling rough and stalling but only when hot...

I believe the first spark plug, with the .011 difference, also reeked of gas, even hours later...

I was just posting to maybe find out what else a difference like that would cause. I read somewhere normal should be about every 10,000 miles it will increase about .001. I think it has just over 60,000 on it.
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Old 04-14-2004, 05:44 AM   #6
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Quote:
Originally Posted by DodgeRida67
Slight power loss. Don't let your average saturday redneck tell you gapping your plugs more is better. Trust me, when cars are engineered they spend a lot of time getting the specs on the gaps right.


Quote:
Originally Posted by DodgeRida67
A bigger gap than specs call for cools down your spark which inturn doesn't ignite your fuel as well causing a power loss. .01 is not much of a difference though.
Everytime you almost stop before you make a fool of yourself, but then...

Excessive gap does not "cool" the spark because the spark is not there to cause heat. Too much gap will prevent or cause a weak spark due to insufficient voltage which will cause a power loss.

As for your assertion that .010" extra gap isn't that much, for some engines that is 30%+ more than the proper gap. In my book that's alot. I should also point out that for every extra .010" gap, you need about 10-15k more volts from your secondary ignition to fire. That is a butt load in anybody's book.
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Old 04-14-2004, 02:01 PM   #7
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Quote:
Excessive gap does not "cool" the spark because the spark is not there to cause heat.




On a serious note, this should go in the thread called "dumbest thing someone ever said to you"(or something like that)

A spark ignites gasoline from the heat it generates. Not just for being a spark.
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Old 04-14-2004, 02:41 PM   #8
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PHP Code:
A spark ignites gasoline from the heat it generatesNot just for being a spark


So what your saying is that if I heat up gas with an electric element heating with no flame that the gas will burn? Gee, I always thought you needed a spark or some sort of burning action.

Your right, what you said should go into the "dumbest things ever said".

If you missed vwhobo's point, and it's obvious you did, he was saying that due to the excessive gap, no spark would occure (not enough electical potential energy to jump the gap), and therefore due to no spark there would be no heat.
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Old 04-14-2004, 07:06 PM   #9
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Quote:
So what your saying is that if I heat up gas with an electric element heating with no flame that the gas will burn? Gee, I always thought you needed a spark or some sort of burning action.




Alright you brainy people. If it's all in the spark and not the heat, how does a diesel engine ignite?

THIS is a fact and theres no use arquing over it: The HEAT is what ignites the fuel. The spark IS heat. That's what a spark is genuises. A slightly bigger gap, (if the voltage will still arch) will WEAKEN the spark, lessen the heat of the spark, AND inturn not ignite the fuel properly.

Just so I can stick this on a post-it and not loose my mind everytime some know-it-all wants to arque, why do you want to purposely follow every post I make, and make an arqument out of it? And um, don't try to blame it on me. The people who come here for help, that dont stick around are people with lives. They get mad at you people for acting like you do. I help to the best of my ability. Yes, I makes mistakes, we all do. I can't help it if someone needs to know how to replace CV joints but asks for a procedure on U-joints. Not my fault. Don't bitch at me about it.
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Old 04-14-2004, 07:25 PM   #10
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Quote:
Originally Posted by DodgeRida67
Alright you brainy people. If it's all in the spark and not the heat, how does a diesel engine ignite?
Oddly enough you're comparing apples and oranges when you compare gasoline engines and diesel engines. One is called a spark ignition engine and the other is a compression ignition engine. I'll make it real simple for you. Try running gas in a diesel and/or diesel in a gas engine and see what happens. I won't bother with a complete explanation because you wouldn't grasp it.

Quote:
Originally Posted by DodgeRida67
THIS is a fact and theres no use arquing over it: The HEAT is what ignites the fuel. The spark IS heat. That's what a spark is genuises. A slightly bigger gap, (if the voltage will still arch) will WEAKEN the spark, lessen the heat of the spark, AND inturn not ignite the fuel properly.
No, as everyone here seems to understand, except for you of course, is that it's the spark that ignites the fuel/air charge. When heat ignites it, that's what we brainy people know as detonation.

Quote:
Originally Posted by DodgeRida67
Just so I can stick this on a post-it and not loose my mind everytime some know-it-all wants to arque, why do you want to purposely follow every post I make, and make an arqument out of it? And um, don't try to blame it on me. The people who come here for help, that dont stick around are people with lives. They get mad at you people for acting like you do. I help to the best of my ability. Yes, I makes mistakes, we all do. I can't help it if someone needs to know how to replace CV joints but asks for a procedure on U-joints. Not my fault. Don't bitch at me about it.
You're right, people come here asking for help, but all you do is confuse them with your special brand of bullsh*t. So now read this thread very closely.

http://www.car-forums.com/talk/showthread.php?t=2499

How did you f*ck that one up? Or is that everyone elses fault too? Face it, you're too busy making excuses and trying to be the all knowing one to read the questions and ask yourself 'Do I know the answer or should I shut up?'. I vote for shut up.
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Old 04-14-2004, 07:36 PM   #11
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a very small spark can ignite gasoline. that's why you are told to put a gas container on the ground. to avoid static discharge.

A small flame that you can run your hand through can also ignite gasoline, where pouring gas on hot coals does nothing. but throw a little piece of paper on the coals and you better hope you can move faster than the flame.

(btw that is quite cool on a very humid night... just be warned you could burn yourself or potentially die, not to mention the risk of starting a large fire...)
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Old 04-14-2004, 07:39 PM   #12
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This has nothing to do with you personally. This has everything to do with getting the correct information out there so that the people reading this information can be properly informed. That said, lets go into diesel fuel......

Diesel fuel is used in Compression-ignition engines. This means that air is compressed (and yes, heated) above its (with the diesel fuel added) autoignition temperature. Then the fuel is sprayed in at high pressure and once the fuel enters the chamber, it automatically ignites.

In a gas motor, the pressure in the compression stroke heats the fuel/air mixture above its flash point and then a spark is needed to ignite the mixture. The spark does not provide the extra heat needed (it already has enough), it provides the extra energy (probably a better term) needed to ignite the fuel.

Here is a great link that goes into most of the details between the two types of engines.

http://encyclopedia.thefreedictionary.com/Gasoline/Petrol%20engine


Of course I see that others have already answered this. Can't hurt to repeat it though. Maybe it will sink in.

Good job lunatic987 with a very practical example.
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Old 04-14-2004, 07:47 PM   #13
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Quote:
Originally Posted by theman352001
This has nothing to do with you personally. This has everything to do with getting the correct information out there so that the people reading this information can be properly informed. That said, lets go into diesel fuel......

Diesel fuel is used in Compression-ignition engines. This means that air is compressed (and yes, heated) above its (with the diesel fuel added) autoignition temperature. Then the fuel is sprayed in at high pressure and once the fuel enters the chamber, it automatically ignites.

In a gas motor, the pressure in the compression stroke heats the fuel/air mixture above its flash point and then a spark is needed to ignite the mixture. The spark does not provide the extra heat needed (it already has enough), it provides the extra energy (probably a better term) needed to ignite the fuel.

Here is a great link that goes into most of the details between the two types of engines.

http://encyclopedia.thefreedictionary.com/Gasoline/Petrol%20engine


Of course I see that others have already answered this. Can't hurt to repeat it though. Maybe it will sink in.

Good job lunatic987 with a very practical example.
Dead link dude.
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Old 04-14-2004, 07:51 PM   #14
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Stupid linking system. You have to copy and paste. Unless........

http://encyclopedia.thefreedictionary.com/Gasoline/Petrol%20engine
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Old 04-15-2004, 04:40 AM   #15
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On a plug gapped @ a nominal 0.044 inches, a difference of + or - 0.001 inch or 0.002 won't matter much (most gap gages shade trees use - the little square or round ones with some plug manufacturers or auto parts stores name stamped on them) probably will not measure that close.

lager gap is not better is the ignition system does not have the voltage to fire the plug.

The reason for larger gaps on late model cars is to get a stronger spark (more ignition energy) for reliable ignition of cars running lean fuel mixtures and with EGR systems. The ignition system voltages, however, have increased from 20K and 25K volts and gaps of 0.030 inch to 35K - 40K volts and gaps of 0.050 in to 0.054 in

As far as problems, a plug gapped @ 0.010 inches above specification (either worn plug or deliberately gapped) could eventually cause missing or misfiring. This would result, if the ECM did not shut down the fuel injector on the affected cylinder, raw fual being pushed into the cats which are not fond of raw fuel.
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