SP Gap and problems it can cause

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What kind of problems can be caused by having a spark plug gap that is a full .01 inches above spec?

posted by  lunatic987

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.

posted by  DodgeRida67

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.

posted by  lunatic987

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.




Just one plug had that .01 bigger gap out of all of them? That's kinda weird :screwy:

posted by  DodgeRida67

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.

posted by  lunatic987

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.

posted by  vwhobo

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.

posted by  DodgeRida67

A spark ignites gasoline from the heat it generates. Not 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.

posted by  theman352001

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.

posted by  DodgeRida67

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.


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.


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.

posted by  vwhobo

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...)

posted by  lunatic987

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 (http://)


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. :thumbs:

posted by  theman352001

Dead link dude. :doh:

posted by  vwhobo

Stupid linking system. You have to copy and paste. Unless........

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

posted by  theman352001

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.

posted by  tbaxleyjr

I can't believe you people are so damn ignorant you think it's not the heat that does it. And then you go and arque over something you don't know what the f your talking about. It's all in the heat. You hold a flame to paper and the paper burns because of the heat from the flame, it's not magic that the flame moves on to the paper.

And wow, some really ignorant soul said "pouring gas on hot coals does nothing" damn buddy, I'd hate to be around you with anything dangerous.

posted by  DodgeRida67

Do you just sit at home all day long and think of stupid things to post? I suggest that instead of resting on your laurels as an "electrition and machinic" (I hope I spelled those the way you do) maybe you should do something productive... Like get a clue. :banghead:

posted by  vwhobo

Combustion is a chemical reaction where hydrocarbons (aka fuel) is combined with oxygen (found in air) in the presence of energy (aka heat) to release more energy than is required to start the reaction

The amount of of energy (heat) required to initiate the reaction is dependent on several variables: the pressure under which the reaction is occuring, the fuel air ratio, presence of other substances, etc.) The guy @ GM, Ford, Diamler Chrysler, etc who is deisgning an ignition system understands these variables including how much energy is required to ignite a fuel air mixture or varying ratios under about 150 psig pressure. This energy requirement is translated into spark plug gap and subsequently, ignition system secondary voltages.

If one wants to go into the gory details of exactly how this works, a good general text targeted to Senior level college engineering students is titled "Internal Combustion Engines * by E.F. Obert, P.E. General level data on ignition energies can be found in a good handbook such as Marks Mechanical Engineering Handbook, a chemistry/chemical engineering handbook or a college level chemistry text.

posted by  tbaxleyjr

Gasoline will ignite when a heat source or electrical spark of at least 853 degrees comes in contact with it. Heat your combustiom chamber tto 860 dgs- no problem----Holy shit, here come the spark plug. :laughing:

posted by  lectroid

can you believe that it can cool off the coals? amazing isn't it? A flame, spark, etc. is a focused source of energy. it is able to ignite the chain reaction. The spark plug controls the reaction by starting it at a specific point. if the heat alone is what would be needed for the reaction, then why aren't we all using engines designed like diesel?

as for the gas on coals, I do not propose that you do that. if there is a slight flare up, even a moth landing in the coals, a blade of grass or a leaf being blown by the wind your dead. Paper can ignite in the presence of just heat (and oxygen) easier than gas, probably because gas vaporizes so easily that it doesn't allow oxygen in with the heat, and as a liquid it can transfer the heat.

(on a high humidity night, the gas will spread along the ground, when ignited it spreads out, then is sucked back into the center into a mushroom cloud of flame. Highly dangerous... and no I did not do it. I just watch the idiots be idiots)

posted by  lunatic987

The reason it ignites under those conditions (the gas on the ground, etc.)
is you have the right combination of fuel, air and energy. You also probably have a fuel rich mixture under those conditions

posted by  tbaxleyjr

Correct. Heat alone would not ignite the gas. it took more energy than the coals alone were giving off ( the paper gave more energy into a focused area, igniting the gas around it, and gas gives off even more energy, the start of the reaction.) along with the presence of oxygen.


the amount of heat given off by the spark in and of itself is not enough to ignite the gas, very little of the spark is going to go off as heat. the energy goes from one side of the gap to the other. The spark itself is the energy that ignites the gas, not any heat created by it. Static electricity can ignite gas, but yet it does not burn our hands. 853 degrees eh? water boils at 212. I can't stand water of 120-140 degrees myself. Static electricity can be fun to play with. lol.

posted by  lunatic987

When will DodgeRida get it through his thick little head that just because a spark plug gets hot, that's NOT how it works....It's the spark that does it, that's what they do...SPARK, whithout the spark you'd have a glow plug..and as most normal people here know, a glow plug aint gonna start an SI engine...coz it's called SI for a reason :banghead:

posted by  Cliffy

He has heard people talk about hot spark and cool spark and that is what is in his head. While there are heat ratings for spark plugs, they refer to the spark plugs ability to dissapate heat.

"The term "heat range" refers to the relative temperature of the core nose of a spark plug. The words "hot" or "cold," when used in referencing spark plugs, are often a source of confusion and misunderstanding, since normally a hot spark plug is used in a cold engine (low horsepower) and a cold plug in a hot engine (high horsepower). The terms actually refer to the heat rating or thermal characteristics of the plug; more specifically, the plug's ability to dissipate heat from its firing end into the engine cooling system."

Read more at:

http://www.edelbrock.com/automotive/sparkplugs.html

Once he can get over this, he can realize what we have been talking about and truly be informed.

posted by  theman352001

.
.
I wouldn't count on him "learning" anything.
.
.

posted by  BavarianWheels

Bullshit, spark is the heat. Static electricty can and does goes beyond 100K volts ( very little amperage )/ so you don't feel the heat ?/ gasoline has no feelings.

posted by  lectroid

That's how it is. Learn it people. It's the heat from the spark (a spark is heat) that ignites the fuel.

posted by  DodgeRida67

Could you be anymore....wrong?

That's bullsh*t. I know all about heat ranges and what they are. I'm saying that the heat from the spark (spark is heat) ignites the fuel. That's how it is. Get the F over it and admit your ignorance people.

posted by  DodgeRida67

I'm gonna ask you a very simple question now...how old are you and how many years experience do you have with cars? because I know that most people here, that you are calling ignorant, have atleast 15 years behind them :fu:

posted by  Cliffy

this could go on forever :banghead: :banghead: :banghead: :banghead: :banghead: :banghead:

posted by  lectroid

I don't care if you are a damn car, if your wrong, your wrong. Deal with it. Screwy people :screwy:

posted by  DodgeRida67

http://www.ankn.uaf.edu/VS/magneto.html


There, check that out. I'm going to stick with this until you fools learn the most basic crap.


Incase your slow to read that site I sent you, and stop at the first few sentences, I'll quote the point.

posted by  DodgeRida67

Dont get me wrong, I love cars...but not to the extent that I am one :thumbs:

posted by  Cliffy

Ya know what ? I think eveyone got lost in this thread :laughing: What was the question ? :ohcrap:

posted by  lectroid

The spark has lots of voltage. It gives the energy needed to make the fuel combine with the air.

Yes heat is created. But it's the energy from the spark that starts the reaction. A spark plug is not a glow plug.

as per my previous example, hot coals have a lot of heat, but failed to ignite the gas. the spark gives the energy needed to activate the fuel/air reaction

You called the spark Heat. The spark itself is not heat and does not ignite the gas because of it's 'heat'.

you should agree that a spark is electricity. Electricity is not heat.

Heat: A form of energy associated with the motion of atoms or molecules and capable of being transmitted through solid and fluid media by conduction, through fluid media by convection, and through empty space by radiation.

Electricity is not the motion of atoms, but of electrons. Electricity can cause atoms to move and vibrate. Hence, how a toaster works.


does that explain things enough or should we go on?

posted by  lunatic987

How to win freinds and influence people, and get your ass kicked at the same time///in my world. :doh: :laughing:

posted by  lectroid

Although written towards two cycle engines, this is a well written simplified discussion of what I was referring in a couple of my engineering texts

The bottom line here is a plug gapped 0.01 inch wider than spec may not create a spark with enough energy to ignite the lean fuel air mixture under 150 psig pressure, cause misfireing and the subsequent headaches

posted by  tbaxleyjr

Please refer to "LIGHTNING 101" :ticking:

posted by  lectroid

A definition of heat from Websters Dictionary (http://www.m-w.com/cgi-bin/dictionary) e (1) : added energy that causes substances to rise in temperature, fuse, evaporate, expand, or undergo any of various other related changes, that flows to a body by contact with or radiation from bodies at higher temperatures, and that can be produced in a body (as by compression) (2) : the energy associated with the random motions of the molecules, atoms, or smaller structural units of which matter is composed f : appearance, condition, or color of a body as indicating its temperature

definition of spark from the same source: a luminous disruptive electrical discharge of very short duration between two conductors separated by a gas (as air) b : the discharge in a spark plug c : the mechanism controlling the discharge in a spark plug

What happens from an engineering and a physics perspective without going through the calculus to explain it is the spark is essentially a discharge of electrical energy. This electrical energy is converted to heat during this discharge since the air gap in the plug acts as a resistor since a certain energy at a certain voltage is required to ionoze the mixture ald allow the spark to form). The larger the gap, the more resistance or the more energy required and voltage required to ionize the mixture . The leaner the fuel air mixture, the more resistance. (the more energy required The electricity passing throgh this resistance is converted to heat energy similar to what happens on a stove when the electricity passed through the calrod element

Voltage gradient is what drives the electricity (similar to a pump driving water) The higher the voltage (30000V + in modern systems) the greater the gap the larger the gap the electricity can jump. If the voltage is not high enough the spark cant jump the gap hence why you don't overgap the plug unless the ignition system voltage is raised (the original question)

Energy is what lights off the fuel mixture. In theory, fuel air mix, as long as it is above the minumum required for combustion, does not care what the source is, as long as it is above the ignition temperature. What it does care about is it is at a certain level measured inorder between .00005 - .00010 joules (a btu is equal to a little over 1000 joules)

The reason for using a spark is simple - with the compression ratios involved in a spark ignition (SI) engine and the speeds a SI runs using a spark which forms and dissipates at the speed of light can provide the energy at the proper temperature and be timed precisely to fire at the right point to get the maximum power and efficiency from the engine

posted by  tbaxleyjr

I think weve beaten this subject to death

The bottom line here is a plug gapped 0.01 inch wider than spec may not create a spark with enough energy to ignite the lean fuel air mixture under 150 psig pressure, cause misfireing and the subsequent headaches

I've tried to use my 20+ years experience as a mechanical engineer to explain physically what is going on during the combustion process. My last response is a digression from the web site lectoid posted to help connect heat and energy and tie the concepts together.

It is not an emotional issue to me. Science, physics and engineering is just that - science, engineering, and physics. These concepts as they apply to cars are not new - They are discussed in a text someone gave me dated 1927 thus in my mind are time tested and true

I am finished arguing this subject. I think the facts have been stated in a simple manner where the target audence of the forum understands.

posted by  tbaxleyjr

PLease don't waste your time arquing. Your flat wrong.



Incase the last site didn't get you there, heres a very in-depth explination of spark plugs.
http://www.stealth316.com/2-sparkplugtech.htm


and heres the main point I want you to read from it:

posted by  DodgeRida67

Listen up class. Today if you understand this lesson you graduate from 1st grade.

#1 notice the "spark" is called a flame kernel. I wonder why...OH YEAH. I know why. Thats why were here.


#2 heat and gas ionization caused by the electrical energy of the spark

Energy is not create or distroyed. It is converted. Electrical energy CAN NOT DO CRAP towards igniting fuel. When it jumps the gap the electrical energy is CONVERTED to heat. That ignites the fuel.


If you understand this class, you then can move on. Otherwise.... :banghead:

posted by  DodgeRida67

Okay Bozo, just to humor you I'll play your silly game. On average, what is the temperature of the spark?

posted by  vwhobo

I don't know. Why dont you tell me? Stick your pea-sized head in a cylinder and find out :hi:




Edit: vwhobo, you fail.

posted by  DodgeRida67

It's amzing not only that it took you 10 minutes to type that but also that with all your bullsh*ting you can't even answer a very basic question that would help to substantiate your theory. There must be a number, give it to us.

By the way, based on what you posted earlier, you have no concept of what a flame kernel is.

posted by  vwhobo

You said a spark is heat, now you say it's electrical energy. Make up your mind. lmao.

Your quoting what we are saying, yet getting a slightly different interpretation. Get this. Heat is not electricity. Electricity can create heat. Incandescent and Flourescent light bulbs both create heat. Just incandescent is a better heater than a light producer. A toaster is another example. Electricity does end up heating up the medium it is traveling through. I'm not arguing that fact.

you need to read this. It's from a page explaining the point to platinum plugs::

"Another issue that plug manufacturers talk about is "unshrouding" the spark so it has a better opportunity to ignite the fuel mixture. Opening up the spark also means the flame kernel it creates can expand more rapidly and evenly inside the combustion chamber, reducing the chance of the flame kernel being quenched and a misfire occurring."

now, a spark is not a flame kernel. A spark is not heat. It is electrical energy. The electrical energy goes through the air/fuel mixture causing it to begin the combustion process. Yes heat is created. But quit calling the spark Heat or the flame kernel. Electricity is NOT heat. Electricity is not Flame. Yes it is all forms of energy.

posted by  lunatic987

Alrighty, sitting here eating pizza and I though of something to sink everylast one of you. Tell me how a cigarette lighter works. The kind you buy at a gas station for about a buck.






Thought so.

posted by  DodgeRida67

Now, tell me, how does the lighter create a flame by the spark? There is no "electrical energy" there. Don't say im comparing apples and oranges, thats bull. It's the heat from the spark. Always is :hi:

posted by  DodgeRida67

Actually yes it does, it's from resistance.

posted by  DodgeRida67

A spark is VERY VERY hot. It is heat. Someone asked how come you cannot feel the burn, it's like this. How quickly is a spark there, and then not there? VERY VERY FAST. Just like that, it's there then its gone. You don't feel the burn because of the speed. Touch a hot peice of something very quickly, you wont feel it. Leave it on there and you definately will. Do the same with a flame. Run your hand through a flame right quick, nothing. Hold it in there - yikes.



Basically I'm sick of losers spewing bull and then blaming me for spewing the bull.

posted by  DodgeRida67

a good apark will burnn you too - ask a lightning strike victim

posted by  tbaxleyjr

my Quote:
Electricity does end up heating up the medium it is traveling through. I'm not arguing that fact.

your quote:
Actually yes it does, it's from resistance.

wtf are you arguing???? I said YES it heats up the medium it is traveling through. Then you say Actually yes it does..... Read what is posted before arguing with it.


Now, as for sparks.... read this then I will make a distinction in 2 types of sparks

"If you strike iron or steel with flint, the flint flakes off tiny particles of iron. The force of the blow and the friction it creates actually ignites the iron, and it burns rapidly to form Fe3O4. The sparks that you see are the hot specks of iron burning!" http://people.howstuffworks.com/flintlock2.htm

Now, those sparks are specks of iron that are burning. Burning something produces . That's not an electrical spark. The spark in a spark plug is an electrical spark. That's Electrons moving from one side to the other. Maybe thinking of it this way will help. Heat is basically the atoms vibrating and moving.

"For example, in the case of a gas like air, the molecules of gas are all free from each other, and they're all flying around smacking into each other at high speed. If you put more energy into this mixture, the atoms will move faster. In other words, heat energy is nothing more than the kinetic energy in the hot material. "

posted by  lunatic987

yes you can get burned. Because it heats you and the air around it up. By quite a bit. Not because the spark is heat, though. An electrical spark is NOT heat.

posted by  lunatic987

**** it - your hopeless.

posted by  DodgeRida67

Oh yeah, Why does the burning flint ignite the lighter? ( heat, heat. )

posted by  DodgeRida67

I'm hopeless because I know that electricity is not heat? how about this. Go talk to a real expert, not just searching websites, because as you should know, you can't believe everything you read, especially online.

posted by  lunatic987

You were comparing the spark of a spark plug to the 'sparks' that you see coming from flint on steel. those 'sparks' are burning flecks of iron. That is beyond apples and oranges. your comparing apples and pickles. By the arguments you present, the person that poured gas on the coals should have been toast. It took something that burnt at 451 to provide the energy needed to ignite the gas.

spark1 ( P ) Pronunciation Key (spärk)
n.
1 An incandescent particle, especially:
One thrown off from a burning substance.
One resulting from friction.
One remaining in an otherwise extinguished fire; an ember.
OR
2 A flash of light, especially a flash produced by electric discharge.
3 A short pulse or flow of electric current.


Flint lighter is 1. Spark plug is 3.

posted by  lunatic987

Amazing... according to what I just asked, hot coals are at 1600 degrees Celsius. Ok, even accounting for a loss of temperature that should still ignite gas correct? Oddly enough that person was not toast.... Long complicated reason why, we'll give up on that for now ok? You said that a spark is heat. If an electrical spark is heat then why can't we use all the heat we produce to create electricity since your calling them the same thing?

As someone I mentioned this to today said. "A spark is a spark. Heat is Heat."

Read this closely:

"Heat is thermal energy that's flowing from one object to another because of a temperature difference between those two objects. Whenever an object contains thermal energy--which it always does--the atoms and molecules in that object are jittering about microscopically. Each atom or molecule isn't completely stationary; instead it is vibrating back and forth, and pushing or pulling on its neighbors. The object's thermal energy is the sum of the tiny kinetic and potential energies of those atoms and molecules as they move back and forth (kinetic energy), and push or pull on one another (potential energy). The hotter an object is, the more thermal energy each of its atoms has, on average, so this thermal energy tends to flow to a colder object when you touch the two objects together. When that thermal energy is flowing from the hotter object to the colder object, we call it "heat.""

Now, first sentence completely rules out a spark as heat. the difference between the gap is a charge difference. One side is positive, the other negative. Not a temperature difference. Now, to restate to eliminate confusion and in a way we are all saying the same thing. the spark provides the energy needed to activate the reaction. I am not saying heat does not ignite gas. If I did it's obvious I would be wrong. As stated, cigarette lighters prove that. But an electrical spark is not heat. Heat is produced in what the spark is 'traveling' through, but the spark is not heat. You need to understand that fact.

posted by  lunatic987

Ok OK I think weve run this into the ground -

posted by  tbaxleyjr

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