Just changed the spark plugs

[Pacfanweb]

Originally posted by: Iron Woode
very interesting thread.

let's take my old school Mopar as an example.

I am running the factory electronic ignition. My ignition puts out roughly 45,000 volts. Points were much lower usually in the 25,000 range. A coil is nothing more than a step-up transformer, with max voltage based on the ratio of windings.

Throughout the 70's, spark plug gaps got wider and wider. Some up to .060. The reason for this was due to the very lean air/fuel mixtures for emissions and fuel economy. The larger gaps allowed a longer duration spark in order to ignite the mixtures.

In a performance situation, finding the optimal plug gap is a tedious procedure. The results are usually very small, but every bit counts.

as for a flooded carbed engine, the solution is simple: pump the gas pedal 3 times and hold it to the floor while cranking the engine over. It will start after 10 or 15 seconds. I have never seen this procedure fail, assuming the engine does run properly in the first place and the battery is good.

Agree with most, except the "pump the gas 3 times when flooded". You don't want to pump the pedal, as that squirts more gas into an already-flooded engine. What you do there is hold the gas wide open and crank the engine.
That's what mechanics are taught, anyway. I suppose lots of people have had varying results, but that's the generally accepted way to start a flooded carb engine.

And "longer duration spark" pretty much = bigger spark...as I have been saying.

 

[LTC8K6]

"And "longer duration spark" pretty much = bigger spark...as I have been saying."

Nope. Duration does not equal bigger or hotter. Nice try at a save, though.

Notice the term "allowed", rather than "caused" or "created".

Really, if you think a different spark will do all that much, put in an MSD system and have multiple "big" sparks to burn your mix.

I mean, if opening the gap gives a noticeable mileage increase, then opening the gap and having 2 big, strong, sparks ought to make even bigger gains, right?

Hey! I know! Why don't you put 2 (or more) spark plugs in for each cylinder!

Now there's a novel idea! :laugh:

 

[Pacfanweb]

Originally posted by: LTC8K6
"And "longer duration spark" pretty much = bigger spark...as I have been saying."

Nope. Duration does not equal bigger or hotter. Nice try at a save, though.

Notice the term "allowed", rather than "caused" or "created".

Really, if you think a different spark will do all that much, put in an MSD system and have multiple "big" sparks to burn your mix.

I mean, if opening the gap gives a noticeable mileage increase, then opening the gap and having 2 big, strong, sparks ought to make even bigger gains, right?

Hey! I know! Why don't you put 2 (or more) spark plugs in for each cylinder!

Now there's a novel idea! :laugh:

You're getting off on a tangent, into hypothetical stuff that's irrelevant.

I never said that opening the gap would make everyone see a mileage increase. In fact, I gave and made note that I was giving one specific example.

Opening the gap WILL give you a bigger spark. That's common sense. It has to be bigger to jump the bigger gap. There's no reason to expect a longer duration spark, unless you're counting as "longer duration", the extra unmeasurable amount of time the spark takes to jump the bigger gap.
Again, you say you're good a Google. Google it, and you'll find MANY, MANY people backing up what I say. Call Accel or MSD and ask them.

Me? I KNOW this is the case. I have a CC degree in automotive repair where I was taught this. I worked at the largest car dealership in the Southeast, where all the professional mechanics there (myself included) knew it. My Ford certifications taught it.
The Explorer example was known to Ford techs back then, and Ford themselves.
The old "backing the coil wire off to get a bigger spark" trick for flooded vehicles is as old as internal combustion itself. If you don't know that one, you haven't been a mechanic for very long.

No, putting an MSD on a stock vehicle probably won't do much, and I never said it would. Putting one on an older, 70's, early 80's carb vehicle very well might. But today's precisely controlled OBDII engines? Not so much. Their ignition systems are already the strongest one ever used in production cars. No need to upgrade those until you do some modifications elsewhere.
So getting even bigger sparks won't help anything, as you are suggesting (sarcastically, and totally missing the point), since the current ignitions are already plenty strong. Won't hurt anything, but all you'll gain is a lighter wallet.

As far as putting the 2 plugs per cylinder....already done many times. Varying results...it was mostly for emissions, as I recall. First one that comes to mind were the old 4 cylinder Rangers with twin plugs. REAL fun to replace the intake side plugs.

And no, it wasn't a "save". And "allowed" is EXACTLY the same in this case as "Caused".
Using Ironwoode's info, if the longer duration (I would still debate that, but let's assume it's right) is "allowed" by a larger gap, then that means it wouldn't happen without the larger gap, so the larger gap CAUSED and even CREATED that "longer duration" spark.

 

[LTC8K6]

Are you going to document the Explorer story or not?

That seems to be the crux of your posts.

Also, lighten up, Francis.

 

[Pacfanweb]

I just documented it. Look above, I wrote it a couple of times. I'm a former Ford tech. I was there, I did it. So it's either true, or I'm lying. I don't think I have a reputation for lying here, or anywhere else for that matter.

And how would you propose I document a story on 91-9 3 model vehicles? It was well-known back then. If you Google the things I've told you to, you'll find many instances of increasing the plug gap causing increases in gas mileage. You say you can Google...do it. Don't believe me. But you'll find that the preponderance of evidence will back me up.

This is common knowledge...it's not like I'm revealing the secrets of the universe that only a few know about here.

 

[nakedfrog]

If only the garage was heated, I could head out there and have a look at the spark I get from various gaps with my test plug

 

[Pacfanweb]

Originally posted by: nakedfrog
If only the garage was heated, I could head out there and have a look at the spark I get from various gaps with my test plug

You know, that reminds me....the local hot rod store used to have an MSD demonstration machine.
You could switch from a standard ignition to an MSD to see the difference right in front of you.

It would let you increase the gap. (wasn't a spark plug, just two metal tips the spark jumped between.

You could see a noticeable difference with both ignition systems when you increased the gap.

The MSD was impressive....lots of sparks.

 

[LTC8K6]

Well, they wanted to sell you on MSD after all, and it really is useful for certain folks. Naturally they set up an impressive demo. My guess is that the demo increased the voltage as the gap got wider.

No one is arguing the point about larger gaps per se.

A larger gap does not magically make your coil put out a higher voltage or a stronger spark, or whatever you wish to call it.

I believe you made that claim earlier.

In fact, you made an even stranger claim.

"As the plugs wears, you get a hotter spark."

You certainly did not limit yourself to early Explorers, either.

I am going to the junk yard tomorrow to get some old plugs to put in my car.

Why google when I can experience the improvements of worn out plugs for real?

You seem to have made several odd claims, but I haven't time to test them all.

If only I'd known these things long ago...

 

[Pacfanweb]

Originally posted by: LTC8K6
Well, they wanted to sell you on MSD after all, and it really is useful for certain folks. Naturally they set up an impressive demo. My guess is that the demo increased the voltage as the gap got wider.

No one is arguing the point about larger gaps per se.

A larger gap does not magically make your coil put out a higher voltage or a stronger spark, or whatever you wish to call it.

I believe you made that claim earlier.

In fact, you made an even stranger claim.

"As the plugs wears, you get a hotter spark."

You certainly did not limit yourself to early Explorers, either.

I am going to the junk yard tomorrow to get some old plugs to put in my car.

Why google when I can experience the improvements of worn out plugs for real?

You seem to have made several odd claims, but I haven't time to test them all.

If only I'd known these things long ago...

Whether you want to call it a hotter spark or larger spark...whatever. I said earlier that bigger spark might be a better description. But go ahead and nitpick. Keep switching back and forth after we've moved on to other things.

A larger gap DOES give you a bigger spark. How can it not? It's a bigger gap, it takes a bit more oomph to get the spark across. Don't believe me, ask someone who has an EE degree and knows car ignitions.

So my claim that as the plug wears you get a hotter/stronger/bigger spark is valid. The plugs don't have to be literally worn.....a worn plug automatically has a bigger gap.

And no, having a bigger gap is NOT limited to old Explorers. I only said, and you might want to re-read since you obviously didn't understand it, that the Explorers were a specific example of getting better gas mileage.

So go ahead and make fun of it.....I can see why Roger got pissed and left this place. You come in here and try to help people with a lifetime's worth of knowledge, not to mention numerous certifications and schools, and Car and Driver/Hot Rod-reading internet jockeys who have done a few tune ups start coming in here and telling you you don't know what you're talking about.
Yep, that's enough to piss off the Pope.

Read this very slowly: Go Google what I've asked you to several times. You obviously have not, or you'd be in here telling me that maybe you were wrong. You certainly won't find much proof that you are right. Or, you can keep coming back and telling me that I'm wrong without providing ANY proof whatsoever....whether anecdotal, linked, or otherwise.

 

[Pacfanweb]

BTW, I asked a friend who is an engineer on another forum to provide me with a detailed explanation, like my school instructors used to give. I'll paste it here with a link a bit later.


But suffice to say, the coil DOES increase the voltage to jump a higher gap.

 

[nakedfrog]

An increase in voltage at the cost of current would be my first guess.

 

[Pacfanweb]

Originally posted by: nakedfrog
An increase in voltage at the cost of current would be my first guess.

Pretty damn good guess...

Jeepforum.com
Keep in mind, he's relating to potential ignitions used on Jeeps, but the general rules here applies to all ignitions. I asked him basically if larger gap=bigger/hotter/whatever spark.
I got an answer much like the electrical instructor in my CC gave. I know all this, but it's been so long since I heard it explained this way that I lost the ability to fully explain it myself. I long ago just accepted this as fact:

This is a VERY good question, one I'm asked frequently, and it takes a lot of time to answer each time, so I'm posting the answer in the open forum.
Easier to link it it that way...

This will take a fairly complicated explanation, so bear with me please...

The ignition coil is 'Saturated' by running current through the primary side wiring.

'Saturation' doesn't mean 'Charging', coils don't charge, they have no capacity to store electrons.

'Saturation' means the primary winding have developed a full size magnetic field (electro-magnet) and that magnetic field has 'Saturated' all parts of the ignition coil windings.


.................

Now that you have a Magnetically 'Saturated' coil,
You open the primary circuit,
(breaker points opening, or module opening the primary circuit)
And that magnetic field collapses around the iron core in the center of the coil.

In the process, that magnetic field moves through the SECONDARY WINDINGS.

Moving Magnetic fields through a conductor, in this case, the secondary windings, excites electrons in the copper of the windings, and creates your high voltage discharge.
.....................

Your ignition coil is a 'Transformer'.
It 'Transforms' a 12 volt electrical charge into a Magnetic Field.
When the current is cut, it 'Transforms' the Magnetic Field into High Voltage by moving the Magnetic Field through many more windings than the 12 volt coil had.
(with modern E-core coils, around 85:1. That means for every turn of the 12 volt primary coil, the secondary has 85 turns)
............................

That high voltage WILL find a ground... Period. (more on that in a minute)

The voltage will continue to rise in the secondary windings,
As that magnetic field continues to collapse through it,
Until the voltage becomes sufficient to jump any air gap, or through any insulation to find ground!

Once the process is started, it can't be stopped, and the coil secondary voltage WILL CONTINUE TO INCREASE until it is sufficient to find ground. PERIOD.

By opening up the plug gap, (Widening the air gap) you are forcing the secondary voltage to continue to rise until it reaches levels that will jump that larger gap.
And believe me, the voltage created in modern E-core coils WILL find a ground!

SO,
You increase the gap, and the voltage has to build more to jump that gap...
In the process, the voltage goes up, but there is no free lunch, and that extra energy for extra voltage has to come from somewhere, so the AMPERAGE is traded for Voltage.

AMPERAGE IS THE 'HEAT' in the spark, not increased Voltage.

When you generate a welding arc, it's not the voltage, but the Amperage that creates the 'HEAT' in the transfer.
Most welders operate at 25 volts or less, but at ranges around 100 Amps!

Anything over about 35,000 volts will fire the spark plug gap in a gasoline engine, even with a lean mixture,
And that is achievable at about 0.045".
Much over that and you are wasting amperage to make more voltage.

Going over that 35,000 volts is wasting AMPERAGE the coil has to convert into Voltage for the larger gaps...
............

Voltage and Amperage have been covered, but there is a third component of spark energy you should consider also,
DURATION. How Long the spark lasts in the gap.

This is usually a component of coil design.
IF the coil is designed to shape and control the collapse of the magnetic field correctly, the duration will be longer...
BUT,
It's also effected directly by the Firing voltage required to get the arc started.

Look at it this way,
You have a LONG discharge coil, but if the first 2/3 of the discharge is wasted building excess voltage to jump a huge gap, you are down to 1/3 of the firing time this coil could provide.

So excess Voltage wastes both Amperage and Duration...

And jacking open the plug gap too far will only result in a thin, 'thready', low amprage (low 'Heat') white or yellow spark (depending on how much moisture is in the air)...

You will be MUCH better off with a 'Thick' blue spark that lingers in the gap.
This is an indicator of both good duration, and sufficient amprage in the discharge.
These are general rules, for guys that don't have Oscilloscopes and adapters for those kinds of voltages to check out what the spark is doing...
----------------------------

Here is something else to think about,

If you get the gap TOO big, or you have some other restrictions in the secondary high voltage system,
Excess gap between the center button in the distributor cap and rotor, excess gap between the rotor and plug wire terminals, rotor phasing out of time and the rotor is between plug wire terminals, bad plug wires with large air gaps, ect...
OR,
Some dip stick just decides to pull the coil wire or a spark plug wire off for this or that without using a test plug...

The voltage in the coil SHOOTS TO THE MOON!
E-core coils can easily produce over 100,000 volts when the secondary path is 'Open'...

That coils IS GOING TO DISCHARGE, PERIOD! NO MATTER WHAT.
Since you don't have a controlled path for it to follow,
It's going to discharge in an UNCONTROLLED MANNER...

This means blasting through it's own insulation internally in most cases.
This will ruin a few windings each time this happens, so you may not notice right away... But that coil is DAMAGED every time there is an uncontrolled secondary discharge, and the effects are cumulative. They build up over time...

SO,
NEVER LET YOUR COIL DISCHARGE WITH OUT A CONTROLLED GROUND PATH!
Test plug made from an old spark plug and a piece of wire is fine, don't pull plug wires or coil wires...

 

[LTC8K6]

How does the coil increase the voltage when the gap gets wider?

It's a fixed device.

Just because the spark jumps .030 and .060 fine, it does not mean that the coil put out a stronger spark for the .060 gap.

If it took longer for the spark to jump, your timing would be off slightly. Now you have added a delay while the charge "builds" to jump the larger gap, haven't you?

 

[Pacfanweb]

Originally posted by: LTC8K6
How does the coil increase the voltage when the gap gets wider?

It's a fixed device.

Just because the spark jumps .030 and .060 fine, it does not mean that the coil put out a stronger spark for the .060 gap.

Read the above and learn, Grasshopper.

 

[Iron Woode]

Originally posted by: Pacfanweb

Originally posted by: LTC8K6
Well, they wanted to sell you on MSD after all, and it really is useful for certain folks. Naturally they set up an impressive demo. My guess is that the demo increased the voltage as the gap got wider.

No one is arguing the point about larger gaps per se.

A larger gap does not magically make your coil put out a higher voltage or a stronger spark, or whatever you wish to call it.

I believe you made that claim earlier.

In fact, you made an even stranger claim.

"As the plugs wears, you get a hotter spark."

You certainly did not limit yourself to early Explorers, either.

I am going to the junk yard tomorrow to get some old plugs to put in my car.

Why google when I can experience the improvements of worn out plugs for real?

You seem to have made several odd claims, but I haven't time to test them all.

If only I'd known these things long ago...

Whether you want to call it a hotter spark or larger spark...whatever. I said earlier that bigger spark might be a better description. But go ahead and nitpick. Keep switching back and forth after we've moved on to other things.

A larger gap DOES give you a bigger spark. How can it not? It's a bigger gap, it takes a bit more oomph to get the spark across. Don't believe me, ask someone who has an EE degree and knows car ignitions.

So my claim that as the plug wears you get a hotter/stronger/bigger spark is valid. The plugs don't have to be literally worn.....a worn plug automatically has a bigger gap.

And no, having a bigger gap is NOT limited to old Explorers. I only said, and you might want to re-read since you obviously didn't understand it, that the Explorers were a specific example of getting better gas mileage.

So go ahead and make fun of it.....I can see why Roger got pissed and left this place. You come in here and try to help people with a lifetime's worth of knowledge, not to mention numerous certifications and schools, and Car and Driver/Hot Rod-reading internet jockeys who have done a few tune ups start coming in here and telling you you don't know what you're talking about.
Yep, that's enough to piss off the Pope.

Read this very slowly: Go Google what I've asked you to several times. You obviously have not, or you'd be in here telling me that maybe you were wrong. You certainly won't find much proof that you are right. Or, you can keep coming back and telling me that I'm wrong without providing ANY proof whatsoever....whether anecdotal, linked, or otherwise.

I think the problem comes from the fact that you are not using the terms correctly. I mean really, oomph?

hotter spark means more intense and that means more current. Voltage is fixed by the coil and so is current. Your point is valid but its moot. There is a difference between factory gap specs and an engine's optimal gap. Any improvement from an increased gap will be short lived.

As for my duration point earlier; its still valid. As any EE can tell you the wider the gap the longer it takes for the spark to jump it and it stays jumped longer as the spark's energy is released. Otherwise, all those after-market ignition modules, like my Chrome box, couldn't claim increased spark duration.

 

[LTC8K6]

"Read the above and learn, Grasshopper. "

You read, cricket.

 

[Iron Woode]

Originally posted by: LTC8K6
How does the coil increase the voltage when the gap gets wider?

It's a fixed device.

Just because the spark jumps .030 and .060 fine, it does not mean that the coil put out a stronger spark for the .060 gap.

If it took longer for the spark to jump, your timing would be off slightly. Now you have added a delay while the charge "builds" to jump the larger gap, haven't you?

Voltage and current vary unless there is a need to max out both.

as for the timing, were talking microseconds here.

 

[LTC8K6]

There's pretty much no current involved, though.

If there were, our plugs wouldn't last long, would they?

 

[LTC8K6]

"as for the timing, were talking microseconds here. "

Yes, we are.

 

[Pacfanweb]

Originally posted by: Iron Woode
I think the problem comes from the fact that you are not using the terms correctly. I mean really, oomph?

hotter spark means more intense and that means more current. Voltage is fixed by the coil and so is current. Your point is valid but its moot. There is a difference between factory gap specs and an engine's optimal gap. Any improvement from an increased gap will be short lived.

As for my duration point earlier; its still valid. As any EE can tell you the wider the gap the longer it takes for the spark to jump it and it stays jumped longer as the spark's energy is released. Otherwise, all those after-market ignition modules, like my Chrome box, couldn't claim increased spark duration.

I agree about my previous explanations, which is why I got an expert to give me a better one.

And the short-lived improvement...if by short-lived, you mean 20k miles or more, then yes.

 

[nakedfrog]

Originally posted by: LTC8K6
How does the coil increase the voltage when the gap gets wider?

It's a fixed device.

Just because the spark jumps .030 and .060 fine, it does not mean that the coil put out a stronger spark for the .060 gap.

If it took longer for the spark to jump, your timing would be off slightly. Now you have added a delay while the charge "builds" to jump the larger gap, haven't you?

Are you positing that the coil outputs it's maximum voltage every time it sparks, no more, no less?

 

[LTC8K6]

IIRC, it was a common practice to pull the center wire and crank the engine over for various reasons.

 

[LTC8K6]

"Are you positing that the coil outputs it's maximum voltage every time it sparks, no more, no less?"

I think Pacfanweb was positing that old Explorers got better mileage on old spark plugs whose gap had opened up, and that installing new plugs with the correct gap reduced the mileage enough for owners to complain about it.

I think I was positing "BS!" regarding that, but in a slightly more polite manner.

I think I am still stuck right there.

I would think that getting a noticeable mileage improvement on your old Explorer by opening up the plug gap would have been big news, and easily documented.

Oh well.

 

[nakedfrog]

Originally posted by: LTC8K6
"Are you positing that the coil outputs it's maximum voltage every time it sparks, no more, no less?"

I think Pacfanweb was positing that old Explorers got better mileage on old spark plugs whose gap had opened up, and that installing new plugs with the correct gap reduced the mileage enough for owners to complain about it.

I think I was positing "BS!" regarding that, but in a slightly more polite manner.

I think I am still stuck right there.

I would think that getting a noticeable mileage improvement on your old Explorer by opening up the plug gap would have been big news, and easily documented.

Oh well.

None of that answers my question

 

[LTC8K6]

"None of that answers my question"

Indeed. I'm glad you noticed.

I'm going to go ruin a coil now, just for fun.

Now, how do you get this silly cover off of this Quad 4?