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Discussion Starter · #1 ·
Hey All,
Have been doing some contemplation about the complete Super-Tune Caper. What I have in mind is going completely though each adjustment procedure and with instrumentation (Tachometer/Dwell Meter, Vacuum/Pressure Tester, Compression Tester, Timing Light, and etc.) setting the 3.14 with the Autolite 4100 at the OPTIMUM adjustment. Am doing this just to see if it CAN be done, and if I am the one who can do it.

One of the most prevalent comments that has been made here is that: What an Engine needs is pretty much individualized, and depends on a LOT of factors.

What the Shop Manual says is mostly for a BRAND NEW ENGINE, and therefore NOT really, or totally applicable to an Engine like the 3.14 with nearly 300,000 miles total, and 136,000 on this rebuild.

So this brings up a "bunch" of questions that need answering.

So far, here are some (there are more, I am sure) of them which will be asked as we progress:

QUESTION: How is the AMOUNT of Dwell that is needed arrived at?

Wouldn't it depend on the Battery, the Alternator, the Voltage Regulator, the Ignition Coil, the Condenser, the Points Gap, and maybe even the Wire Gauge and Resistance used in the circuitry?

If this is so, then HOW can one calculate the Dwell Angle with all these factors dialed in?

If this is NOT so, then what ARE the salient factors?

The 1964 Ford and Mercury Shop Manual has the following listing for a 390 FE in general and the P-Code Engine in particular:

Breaker Arm Spring Tension: 17-20 Ounces (this is how much pressure it takes to open the Points).
Contact Spacing: 0.014 - 0.016 (this is Points Gap?).
Dwell Angle at Idle Speed: 26 - 28.5 Degrees.
Initial Ignition Timing: 4 Degrees BTDC (!)

[THERE IS A NOTE ABOUT THIS: "To obtain optimum engine performance and fuel economy, the initial ignition timing may be advanced 5 degrees over the "normal" setting. No further improvement in engine performance or fuel economy will be achieved by advancing beyond this point. Advance the timing progressively until engine detonation (spark knock) is evident under actual road test acceleration. Retard the timing until the detonation is eliminated."]

QUESTION: Have heard a bunch about "recurving" the Distributor to achieve OPTIMUM results.

Here are the relevant specifications from the Shop Manual:
CENTRIFUGAL ADVANCE:
@400 RPM .5 - 1.5 Degrees
@500 RPM 3.5 - 4.5 Degrees
@800 RPM 5.75 - 7 Degrees
@1400 RPM 8.25 - 8.5 Degrees
@2000 RPM 10.75 - 12.75 Degrees

VACUUM ADVANCE:
1000 RPM 2 - 5 Degrees @ 8"HG Vacuum
1000 RPM 4 - 7 Degrees @ 10 HG Vacuum
1000 RPM 5.5 - 8.5 Degrees @ 15 HG Vacuum
1000 RPM 5.5 - 8.5 Degrees @ 20 HG Vacuum

Maximum Advance Limit 8.5 Degrees

Spark Plugs: BF-32 18MM Gap: 0.032 - 0.036

By the above specifications, if the Initial Advance is 4 degrees, and once can exceed that by 5 degrees, then Initial Advance should NEVER be more than 9 degrees.

Then if the Centrifugal Advance can be up to 12.75 degrees, would THAT be added to the 9 degrees? If it would then we are looking at 21.75 degrees with the Initial and Centrifugal.

And then if the Vacuum Advance can be up to, but not exceeding 8.5 degrees, would that be added to the 21.75 degrees? And if it would then we are looking at 30.25 degrees "ALL IN". Right?

So on Ms. American's 3.14, we are right now sitting at 10.5 Initial, and with the Centrifugal&Vacuum added provide 32 degrees "ALL IN".

NOW, what Ross, Gary, and Mr. B&F are saying is to dial in the Initial Advance to where the MAXIMUM Intake Manifold Vacuum is achieved (with the Vacuum Line FROM the 4100 TO the Distributor disconnected and capped), then back off two degrees, and whatever THAT is will be the Initial Advance.

And apparently the 3.14's Distributor adds another 21.5 degrees (32 (ALL IN) minus 10.5 (Initial)) Centrifugal&Vacuum, so let's say that the Maximum Intake Manifold Vacuum is achieved at 14 degrees BTDC, then we back off of THAT two degrees, making the Initial Advance 12 degrees, then we get another 21.5 degrees from the Centrifugal&Vacuum, that would equal 33.5 degrees which apparently ISN'T all that radical.

So at this point, we have the Dwell and Timing set.

Then it is time to go step-by-step through the settings of the 4100. We've pretty much got the Choke Mechanism adjusted. This tuning would include only the Secondary Throttle Plates Shaft opening, the Idle Mixture settings, and the Hot Engine Idle Speed, and we'd pretty much be at what is best for the 3.14. RIGHT?

Anyway, this should be fun and informative.

JC
 

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QUESTION: How is the AMOUNT of Dwell that is needed arrived at?

Wouldn't it depend on the Battery, the Alternator, the Voltage Regulator, the Ignition Coil, the Condenser, the Points Gap, and maybe even the Wire Gauge and Resistance used in the circuitry?

If this is so, then HOW can one calculate the Dwell Angle with all these factors dialed in?
Dwell mainly has a bearing on coil saturation time... Closer gap on points = increased dwell, and wider gap = less dwell. The dwell spec was easy to use on the old GM dist with the little window, you could adjust the points while the engine was running. Also the GM breaker plate was under the advance weights whice made them hard to get to with a feeler guage. IMO, someone tuning with the dwell setting is REALLY splitting hairs
 

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[THERE IS A NOTE ABOUT THIS: "To obtain optimum engine performance and fuel economy, the initial ignition timing may be advanced 5 degrees over the "normal" setting. No further improvement in engine performance or fuel economy will be achieved by advancing beyond this point. Advance the timing progressively until engine detonation (spark knock) is evident under actual road test acceleration. Retard the timing until the detonation is eliminated."]

QUESTION: Have heard a bunch about "recurving" the Distributor to achieve OPTIMUM results.

Here are the relevant specifications from the Shop Manual:
CENTRIFUGAL ADVANCE:
@400 RPM .5 - 1.5 Degrees
@500 RPM 3.5 - 4.5 Degrees
@800 RPM 5.75 - 7 Degrees
@1400 RPM 8.25 - 8.5 Degrees
@2000 RPM 10.75 - 12.75 Degrees

VACUUM ADVANCE:
1000 RPM 2 - 5 Degrees @ 8"HG Vacuum
1000 RPM 4 - 7 Degrees @ 10 HG Vacuum
1000 RPM 5.5 - 8.5 Degrees @ 15 HG Vacuum
1000 RPM 5.5 - 8.5 Degrees @ 20 HG Vacuum
These figures can be used in Miss 3.14 to verify proper operation of her advance componants. I'd be VERY suprised if her dist could match these specs now, due to age and milage, altho some new bushings and springs and lubrication might bring her back to par.
By the above specifications, if the Initial Advance is 4 degrees, and once can exceed that by 5 degrees, then Initial Advance should NEVER be more than 9 degrees.

Then if the Centrifugal Advance can be up to 12.75 degrees, would THAT be added to the 9 degrees? If it would then we are looking at 21.75 degrees with the Initial and Centrifugal.

And then if the Vacuum Advance can be up to, but not exceeding 8.5 degrees, would that be added to the 21.75 degrees? And if it would then we are looking at 30.25 degrees "ALL IN". Right?
Absolutely CORRECT

And apparently the 3.14's Distributor adds another 21.5 degrees (32 (ALL IN) minus 10.5 (Initial)) Centrifugal&Vacuum, so let's say that the Maximum Intake Manifold Vacuum is achieved at 14 degrees BTDC, then we back off of THAT two degrees, making the Initial Advance 12 degrees, then we get another 21.5 degrees from the Centrifugal&Vacuum, that would equal 33.5 degrees which apparently ISN'T all that radical.

So at this point, we have the Dwell and Timing set.

JC
As you noted from the quote out of the FSM Inital advance can be increased up the the point of pinging (spark knock). The total advance is arrived at by a number of variables, compression ratio, cylinder pressure, cam tiimng, fuel quality and octane, ambient and engine operating temps, ect. when I was racing, I normally ran 40 degrees all in by 2800 RPM. The motor would run even better with slightly MORE timing, but was a bear to start.

On Ms 3.14, I'd verify the centrifical and vac advance was working properly and set the inital at the highest vac reading minus a couple of degrees. shes gonna run GRREAAATT!
 

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Discussion Starter · #4 ·
Dwell mainly has a bearing on coil saturation time.
Hey Mr. B&f,
Have been doing some research on this, and have found a couple of GREAT websites that the explanations are SUPER. There's a LOT to this, and just as the 4100 has a LOT of relativity, so does Breaker Point Electrical Adjustments. From what these websites are saying, MUCH of this SHOULD be done with an Oscilloscope! But then again, the websites were tutorials done as a way to get people to come to their websites, which are sponsored by Instrumentation Companies, makers of Oscilloscopes and other instrumentation made for dealing with automotive electrical systems.

Closer gap on points = increased dwell, and wider gap = less dwell.
Yes.

The dwell spec was easy to use on the old GM dist with the little window, you could adjust the points while the engine was running.
Wish that the Ford Distributor had THAT!

Also the GM breaker plate was under the advance weights whice made them hard to get to with a feeler guage.
But if you could adjust the Dwell with a Screw, you didn't NEED feeler gauges.

IMO, someone tuning with the dwell setting is REALLY splitting hairs
When Ms. American was NEW to the FMF, we were told that using Feeler Gauges were a "ball park" method. That Dwell, was the REAL way to tune! :)

Anyway, I see another post of yours. See you there.

JC
 

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Discussion Starter · #5 ·
These figures can be used in Miss 3.14 to verify proper operation of her advance components. I'd be VERY surprised if her dist could match these specs now, due to age and mileage, altho some new bushings and springs and lubrication might bring her back to par.
Hey Mr. B&F,
Actually, the Distributor on the 3.14 was NEW in 1989. It is a larger diameter unit with HEI style Towers. Was told that the larger diameter eliminated "spark scatter". Had that explained by the fellow mentoring the 3.14's rebuild. Couldn't resist... HAD to have the Distributor that eliminated "spark scatter"! BTW, the 3.14 also has a "windage tray"! Bet not everyone knows what THAT is! :)

As you noted from the quote out of the FSM Inital advance can be increased up the the point of pinging (spark knock).
Well, with the Compression Ratio having been taken down from 10.1:1 (STOCK) to 9.5:1 (recommended by the guys at the Lexington Machine Shop in Houston, Texas), have never had a problem with pinging.

The total advance is arrived at by a number of variables, compression ratio, cylinder pressure, cam timing, fuel quality and octane, ambient and engine operating temps, etc.
That's what I meant by there being a LOT of relativity to this Timing&Advance Tuning.

When I was racing, I normally ran 40 degrees all in by 2800 RPM. The motor would run even better with slightly MORE timing, but was a bear to start.
That was one of the points on one of the websites found.

On Ms 3.14, I'd verify the centrifical and vac advance was working properly and set the inital at the highest vac reading minus a couple of degrees. shes gonna run GRREAAATT!
That's MY feeling about it too. :)

The websites with the Timing&Dwell&Advance information also has information about HEI Systems.

For the first time, am starting to understand how THEY work.

Lorrie Van Haul, the 1967 Dodge P200 Postal Van that is here HAS a NEW "Big Three" HEI System. Dodge Electronic Distributor, Ford HEI Coil, and a GM Electronic Control Module and Heat Sink.

She was running in early November, and the first cold morning, she all of a sudden decided to refuse to start, and she hasn't started since.

Now that Ms. American is Up&Running, am going to be starting on Lorrie Van Haul.

Wonder if we'll EVER have both of them to where they'll both be reliable again?

We'll just have to wait and see. Time will tell.

JC
 

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BTW, the 3.14 also has a "windage tray"! Bet not everyone knows what THAT is! :)

JC
Well...The way I figure it is....Since windage is the term used to figure wind drift on a rifle bullet.......

And since all sharpshooters wet their finger with spit to test the wind speed and direction.......

And since after the wet finger wind test we all wet the front sight or our shootin irons to sharpen the sight picture.......

And since we already have a bullet pouch to carry our bullets and patches and keep them dry......

And since we also have a powder horn to carry our powder and keep it dry......

And since when we see that monster Buck or Bar our mouths get dry, we need a separate container to carry spittle in for the wet finger wind test and to wipe the front sight with......

Sooo...I imagine a windage tray is what hillbilly Ky hunters use to carry their extra spittle supply. But for the life of me, I can't imagine why Ms. 3.14 needs one.

Or.... a windage tray COULD be something entirely different....
 

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Discussion Starter · #7 ·
Or.... a windage tray COULD be something entirely different....
Hey Mr. B&F,
Of the two explanations, THIS is the more correct, but it still doesn't say WHAT a Windage Tray is.

See here:

Milodon Windage Trays - JEGS

Per the description at the above referenced URL, it is a piece of bolt-on equipment that can add up to 20 HP without using any energy from the Engine.

But the above referenced description doesn't say WHAT a Windage Tray DOES.

The purpose of a Windage Tray: The Crankshaft of an Engine can at times actually pick up the Oil in the Oil Pan, and it has been found that the Oil gets "wrapped" around the Crankshaft like a piece of rope or a rag.

The Crankshaft is creating a turbulence due to its rapid rotation. Having the Oil hanging on to the rotating Crankshaft creates "drag" on the Crankshaft that the Engine has to overcome which takes HP.

The Windage try separates the rotating (and thus turbulating) Crankshaft from the Oil supply to prevent the Oil from getting sucked up into the Crankshaft.

The Windage Tray fits between the Rotating Crankshaft and the Oil Pan, and is fastened to the Block using the SAME Bolts that holds the Oil Pan to the Block's bottom Flange.

It was another item like the Distributor that eliminated "spark scatter". And since ALL NASCAR Engines have one, Ms. American got one. :)

Anyone tearing down the 3.14 would find it, and probably wonder what in the hell it is! :)

It is cold here this morning. And it's supposed to get progressively colder as the week wears on, getting down to 28 on Thursday. Also a chance of rain.

Am going to be heading out of here in Ms. American in late mid-morning to go run the weekly errands. Will be able to hit the Post Office and finally send Gary the check for the Choke Mechanism. Need to do the weekly grocery shopping too.

Upon arrive home will be preparing Lorrie Van Haul for her diagnostic tests to see WHY she won't start&run. This is also going to include cleaning up all the Tools&Materials so that everything will once again be findable around here.

So we are off and running on yet another vehicle related caper.

Hope you have a GREAT week.

JC
 

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QUESTION: How is the AMOUNT of Dwell that is needed arrived at?
I think you are putting too much concern on dwell. However, consider it something you need enough of for a given RPM.

At idle, dwell is less important but you need enough to saturate the coil to allow the coil to fire. Basically the primary side gets power and creates a field which needs time to build up, when the primary side is shut off, the secondary field collapses and fires.

The issue is "enough" at idle turns into "not enough" at high rpm. That is because the saturation of the coil are determined by time, but the points operate on a fixed open and close point based on cam position that reduces in time as RPM goes up

In other words, points open and close in a certain amount of rotation of the distributor, no matter whether its spinning very fast or spinning very slow, that duration gets shorter at higher RPM, but the coil, like a sponge soaking water still takes as long as it takes.

So one way to look at it is, you need "enough dwell for your highest RPM"

Some say that points don't have stable dwell, they do for a given period, but induced wear changes it over time, that is one reason electronic ignitions are better in the long run.

Now, modern EFI motors with computer control will actually change dwell with RPM to compensate, pretty slick.

With all that, I ask a question that will lead you to an answer.

If the Ford engineers designed an ignition system to adequately saturate the coil at all expected RPM, then provided a dwell setting to do so, do you think you have changed those operating conditions enough to require something different?

I would say in your application, absolutely not. I'd set the dwell toward the top end of the specs, reset the timing, and forget it. If it was an 8000 rpm small block, maybe, but it just isn't that critical for the rpm range a normal street big block runs

Remember, dwell affects timing, but timing doesn't affect dwell, so always set dwell, then readjust timing.

THERE IS A NOTE ABOUT THIS: "To obtain optimum engine performance and fuel economy, the initial ignition timing may be advanced 5 degrees over the "normal" setting. No further improvement in engine performance or fuel economy will be achieved by advancing beyond this point. Advance the timing progressively until engine detonation (spark knock) is evident under actual road test acceleration. Retard the timing until the detonation is eliminated."
Please ignore the numbers on this quote. It is true. However, there is a term called dynamic compression ratio (DCR) that calculates compression of an engine based on the closing point of the intake valve. It is key here.

When Ford wrote this, there was a stock cam & stock compression. Your cam is more aggressive (however minor that may be) and changed the intake closing point. That essentially reduced DCR. Now lower compression seems bad yes, well yes, but cylinder fill isnt only based on the cam and piston, its also affected by all the other components and as you rev higher, the cam makes MORE power.

So yes there is diminishing return, but no you cannot use the same numbers anymore.

Second point, using your ear to time a motor is very dangerous on a motor that will work hard. You cannot hear damaging knock until its excessive. There are tried and true numbers that are good for FEs which I will address in your next question

Have heard a bunch about "recurving" the Distributor to achieve OPTIMUM results.

Here are the relevant specifications from the Shop Manual:
CENTRIFUGAL ADVANCE:
@400 RPM .5 - 1.5 Degrees
@500 RPM 3.5 - 4.5 Degrees
@800 RPM 5.75 - 7 Degrees
@1400 RPM 8.25 - 8.5 Degrees
@2000 RPM 10.75 - 12.75 Degrees
These are in cam degrees, you need to double it to use it at the balancer. So, ignoring the small steps, you have approx 12 degrees at 2000 rpm = 24 you'll see at the balancer.

24 degrees at the balancer PLUS initial at 12 equals 36 degrees total.

That is perfect for a street FE. Much more than that causes detonation, less gives up power for engines with a big combustion chamber and antiquated chamber design.

Some questions though, at 2000 your quote seems to show that advance stops. You could verify that with a light. Lets say it adds 3 more degrees by 3000. Now you are 15x2 PLUS 12 initial = 42 total

That is too much, and THAT is why you would recurve.

You want to keep the 12 initial, but you dont want as much total, so the recurve will limit total

VACUUM ADVANCE:
1000 RPM 2 - 5 Degrees @ 8"HG Vacuum
1000 RPM 4 - 7 Degrees @ 10 HG Vacuum
1000 RPM 5.5 - 8.5 Degrees @ 15 HG Vacuum
1000 RPM 5.5 - 8.5 Degrees @ 20 HG Vacuum

Maximum Advance Limit 8.5 Degrees
Oh crap you said 36 was perfect and the vacuum advance added MORE LOL

Vacuum advance does not work at wide open throttle (WOT) because vacuum is zero. However, when there is low load and part throttle, vacuum pulls more in to help with mileage.

So, it IS tunable, but its really to help you during cruise for MPG not power

So rules of thumb

36 total at WOT = initial 12 plus (2 times distributor advance) 24 Perfect

For a street car, add vacuum on top of that for mileage gains - you are good

By the above specifications, if the Initial Advance is 4 degrees, and once can exceed that by 5 degrees, then Initial Advance should NEVER be more than 9 degrees.

Then if the Centrifugal Advance can be up to 12.75 degrees, would THAT be added to the 9 degrees? If it would then we are looking at 21.75 degrees with the Initial and Centrifugal.

And then if the Vacuum Advance can be up to, but not exceeding 8.5 degrees, would that be added to the 21.75 degrees? And if it would then we are looking at 30.25 degrees "ALL IN". Right?

So on Ms. American's 3.14, we are right now sitting at 10.5 Initial, and with the Centrifugal&Vacuum added provide 32 degrees "ALL IN".
A repeat but seeing you asked specifically, you are incorrect

INITIAL plus DISTRIBUTOR ADVANCE CONVERTED TO CRANK DEGREES = TOTAL (shoot for 36-38 on a street FE)

VACUUM is NOT additive because when you are in hammer mode, vacuum is zero so its not there

Make sense?
 

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Discussion Starter · #9 ·
I think you are putting too much concern on dwell. However, consider it something you need enough of for a given RPM.
Hey Ross,
Have been doing some interesting research on this.

Do you remember my comment about "The Encyclopedia Of The Way Things Work"? The point that was made was that if I already knew that about which the explanation was talking, that it made PERFECT sense. BUT, if I hadn't the slightest idea of what they were talking about, I couldn't understand the explanation.

Well, that's what's happening now. I'm more and more knowledgeable about the terms and processes that I can NOW understand what is being proffered. And your comment about needing enough dwell for given RPMs.

At idle, dwell is less important, but you need enough to saturate the coil to allow the coil to fire.
So the question becomes: How fast CAN an Ignition Coil saturate? And what are the factors that are involved with Coil saturation? Feel safe in assuming that all this is taking place at the speed of light because that's how fast electricity moves in a circuit. Still when a Distributor is spinning at a given Engine RPM, the time that the Points are closed can be VERY short, even if they are set at the proper angle. AND then, the other side of THAT is that the MORE dwell, the deeper the saturation of the Coil, BUT, if the dwell is TOO much, then there becomes a problem with the amount of time that the Coil NEEDS to discharge.

Basically the primary side gets power and creates a field which needs time to build up, when the primary side is shut off, the secondary field collapses and fires.
I've heard this explained exactly this way, and while I can concede that this is what happens, I have but a cursory understanding of HOW all this manages to function.

From the research, it was found that the "Primary Side" of the Ignition Coil refers to a "soft" Iron Core around which are a number of wraps of wire which becomes magnetized by electricity flowing INTO wraps of wire.

(I remember making "electromagnets" in school. We would take a piece of Iron, wrap it with wire. Hook one end of the wire to the + Terminal of a Battery, hook the other end of the wire to the - Terminal of the same Battery, and the Iron Core would pick up nails, and would make Iron Filings on a sheet of paper move into a pattern that showed the Magnetic Field of the Assembly.)

From the research, it was also found that the "Secondary Side" of the Ignition Coil refers to a somewhat GREATER amount of wire wraps, but don't understand this as well as I do the "Primary Side".

Don't yet understand what the setup is and WHY when the Primary Side is disconnected from the current, that the Secondary Side "collapses" and puts out a High Voltage "fire".

Am understanding that it has to do with the Primary Voltage being at a certain Amperage, and that through the means of the Wire, Iron Core, and the number of wraps of wire in the Primary and Secondary Circuits that what the Coil is doing is increasing the amount of voltage, by reducing the amount of amperage. But I don't have a clear understanding of this process.

The issue is "enough" at idle turns into "not enough" at high rpm. That is because the saturation of the coil are determined by time, but the points operate on a fixed open and close point based on cam position that reduces in time as RPM goes up.
YES. I understand THIS perfectly. 29.5 degrees of dwell at 500 RPM would give a certain amount of time that would be twice as long as it would be at 1,000 RPM. BUT, the Coil still needs the SAME amount of time to saturate.

In other words, points open and close in a certain amount of rotation of the distributor, no matter whether its spinning very fast or spinning very slow, that duration gets shorter at higher RPM, but the coil, like a sponge soaking water still takes as long as it takes.
YES.

So one way to look at it is, you need "enough dwell for your highest RPM".
So what one needs to do is to ascertain how long it takes the Coil's Primary Side to totally (or at least, adequately). Then figure out how many degrees of Distributor rotation at one's maximum RPM would it take to keep the Points CLOSED for that length of time!

Some say that points don't have stable dwell, they do for a given period, but induced wear changes it over time,
Such as: The Rub Block wears down; "Points Bounce"; "Points Float"; Distributor Cam Wear; Distributor Bearings; Friction; and etc.

that is one reason electronic ignitions are better in the long run.
Yes, but still even though it isn't called "dwell" there is still the factor of Primary Coil Saturation time. Am going to have to find out what are the factors involved with Coil Saturation!

Now, modern EFI motors with computer control will actually change dwell with RPM to compensate, pretty slick.
Along with having each Spark Plug have it's OWN Coil. The advances are remarkable, but are, in a way, counter productive, in that the slicker it gets, the more complex it is. And pretty soon one has a system that is not only VERY complex, but EXPENSIVE. When for all practical purposes a SIMPLER, less expensive system would do the same thing, not quite as well, but adequately for most applications.

With all that, I ask a question that will lead you to an answer.

If the Ford engineers designed an ignition system to adequately saturate the coil at all expected RPM, then provided a dwell setting to do so, do you think you have changed those operating conditions enough to require something different?
I would have to say that we haven't. Ms. American's 3.14 isn't significantly changed from what it WAS, and the STOCK system is MORE than adequate for the way she is driven.

I would say in your application, absolutely not.
Have to agree. Still WANTING to know about this stuff, even though it isn't applicable to the 3.14 is more what this is about than the actual putting of it into practice.

I'd set the dwell toward the top end of the specs, reset the timing, and forget it.
Alright.

If it was an 8000 rpm small block, maybe, but it just isn't that critical for the rpm range a normal street big block runs.
Especially when Ms. American is being pampered like Helena Bonham Carter! :)

Remember, dwell affects timing, but timing doesn't affect dwell, so always set dwell, then readjust timing.
REALLY? Am going to have to contemplate THAT now.

Please ignore the numbers on this quote. It is true. However, there is a term called dynamic compression ratio (DCR) that calculates compression of an engine based on the closing point of the intake valve. It is key here.
Doesn't DCR have to do with the momentum/inertia of the flow of Air/Fuel?

When Ford wrote this, there was a stock cam & stock compression. Your cam is more aggressive (however minor that may be) and changed the intake closing point. That essentially reduced DCR. Now lower compression seems bad yes, well yes, but cylinder fill isn't only based on the cam and piston, its also affected by all the other components and as you rev higher, the cam makes MORE power.
More to contemplate.

So yes there is diminishing return, but no you cannot use the same numbers anymore.
The trick is going to be figuring out WHAT numbers need be used.

Second point, using your ear to time a motor is very dangerous on a motor that will work hard. You cannot hear damaging knock until it's excessive.
Never considered doing this, but I can see what you mean.

There are tried and true numbers that are good for FEs which I will address in your next question

These are in cam degrees, you need to double it to use it at the balancer. So, ignoring the small steps, you have approx 12 degrees at 2000 rpm = 24 you'll see at the balancer.
See? I didn't know this.

24 degrees at the balancer PLUS initial at 12 equals 36 degrees total. That is perfect for a street FE. Much more than that causes detonation, less gives up power for engines with a big combustion chamber and antiquated chamber design.
Alright.

Some questions though, at 2000 your quote seems to show that advance stops. You could verify that with a light. Lets say it adds 3 more degrees by 3000. Now you are 15x2 PLUS 12 initial = 42 total. That is too much, and THAT is why you would recurve.
So one should determine the MAXIMUM amount of Centrifugal and Vacuum Advance that is available from the Distributor, then subtract that amount from 36 Degrees ALL IN, and that would give the amount of Initial Advance one should use.

You want to keep the 12 initial, but you dont want as much total, so the recurve will limit total.
So one should set the Initial at 12 Degrees BTDC, and then recurve the Centrifugal to be ALL IN at 36 Degrees. So the next question is: HOW does one "recurve"?

Oh crap you said 36 was perfect and the vacuum advance added MORE LOL. Vacuum advance does not work at wide open throttle (WOT) because vacuum is zero. However, when there is low load and part throttle, vacuum pulls more in to help with mileage.
But if there were a high vacuum, which would give more Vacuum Advance, wouldn't the RPMs be down so that there would be less Centrifugal Advance?

So, it IS tunable, but its really to help you during cruise for MPG not power
I remember when I had the 1942 Mercury, back in 1957, it had a "Motor Minder" on it. I understand NOW what that was. It was a Vacuum Gauge. If you kept the "needle" in the "Green", you would get better gas mileage!

So rules of thumb: 36 total at WOT = initial 12 plus (2 times distributor advance) 24 Perfect. For a street car, add vacuum on top of that for mileage gains - you are good
Alright. So when I get ready to do this FINAL tuning. Will put in NEW Spark Plugs. Set the Dwell at 28.5 Degrees. Set the Timing at 12 Degrees BTDC. Then it is on to the 4100 for a final run though.

A repeat but seeing you asked specifically, you are incorrect

INITIAL plus DISTRIBUTOR ADVANCE CONVERTED TO CRANK DEGREES = TOTAL (shoot for 36-38 on a street FE)

VACUUM is NOT additive because when you are in hammer mode, vacuum is zero so its not there

Make sense?
YES.

And Ross, the NEXT thing is to become familiar with the HEI Ignition System because THAT'S what Lorrie Van Haul's MIGHTY 225 Slant Six has, and she won't Start&Run. She has a "Big Three" HEI System: 1. Dodge Electronic Distributor (which instead of Points&Condenser has a Magnetic Pickup and a Reluctor); 2. Ford HEI Coil; And 3. GM Electronic Control Module and Heat Sink.

Am going to have to go through Lorrie's Engine, Carburetor (Stromberg Model W), and HEI System to find out what isn't functioning properly, and fix it. That's NEXT on the agenda here.

Am finding that having Ms. American back up&running and being street legal again, that am not so stressed. Am sleeping better. :)

Anyway, thanks for the VERY thoughtful response.

JC
 

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that was an exellent description of the ign. sys. coil saturation: current flowing through a wire induces a mag field around it. mag field passing through a wire induces a voltage in it. the movement of the field is the key. a static mag field dosent affect the electron flow. in the coil as current flows in the primary,a mag field is created. at some point the building mag field will oppose the incoming current to the point of stopping it-saturation. when the points open, the stored charge in the condenser pushes the current back through the primary-cauring a rapid collapse of the mag field. that moving mag field induces a voltage in the sec. windings. since the sec are about 1000 times more, the voltage is also much higher than the pri. this happens because both windings are around the same iron core. whew
 

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It still boils down to the magical smoke that is in ALL electronic devices that causes them to work properly and if you ever let the smoke out it ceases to function.... ;) The saturation times of coils is very quick and is really a moot point... IMHO..




MRO.....
 

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Discussion Starter · #13 ·
that was an excellent description of the ign. sys.
Hey Mr. GZ,
Understanding the mechanical part of the Engine, i.e. The Four Strokes, the opening and closing of the Valves, the Crankshaft, Fuel Pump, Water Pump, Cooling System, etc. are all VERY easy to understand. Not so with the Carburetor and the Ignition System. And for the first time, these are becoming understandable. It has taken a long time for that to become the case.

Coil Saturation: Current flowing through a wire induces a mag field around it.

Mag field passing through a wire induces a voltage in it. The movement of the field is the key. a static mag field doesn't affect the electron flow.
These are variation of each other! Interesting...

In the coil as current flows in the primary, a mag field is created. At some point the building mag field will oppose the incoming current to the point of stopping it - saturation.
Hmmmmmm. So saturation happens. WHY? Why doesn't the Magnetic Field just continue to saturate?

When the points open, the stored charge in the condenser pushes the current back through the primary - causing a rapid collapse of the mag field.
This is a whole NEW aspect of the system. From where does the Condenser get its "stored charge"? It obviously is put there from the Negative Terminal of the Ignition Coil since THAT is the Wire to which it is connected.

You see? I don't understand the Condenser either.

that moving mag field induces a voltage in the sec. windings.
That which the Condenser releases is a "moving magnetic field"? It would have to be electronic because the Condenser doesn't ACTUALLY move.

Since the sec are about 1000 times more, the voltage is also much higher than the pri. This happens because both windings are around the same iron core. Whew
Can accept that this HAPPENS, but still don't understand WHY.

BTW, some of the research that has been found lists the TYPICAL Coil as having an 80:1 "turn ratio", i.e. a typical HEI Ignition Coil would have 135 Primary "turns" and the Secondary would have 11,000 "turns", a ratio of 81.48:1.

Alright, NOW have to find out how a Condenser works, and maybe all this will come together.

Thanks for the response.

JC
 

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Discussion Starter · #14 ·
It still boils down to the magical smoke that is in ALL electronic devices that causes them to work properly and if you ever let the smoke out it ceases to function.... ;)
Hey Dusty,
This ELECTRICAL stuff is all VERY mysterious! It's almost as mystical as Quantum Physics. Am doing some learning about QP. Turns out that sub-atomic particles sometimes act as if they are particles, and sometimes act as if they are waves. And there is during the measuring process what is called a "wave collapse". That's where the wave form of a subatomic "quon" becomes a particle. The problem is that they can't figure out where that happens. They even postulate that the wave collapse happens in the observer's mind WHEN the observer becomes aware of it!

The saturation times of coils is very quick and is really a moot point... IMHO..
Alright... BUT what is meant by "very quick". It isn't instantaneous even though the electricity is moving at the speed of light.

To get some perspective of this: A Four Cycle, Six Cylinder Engine has six, 60 degree faces on its Distributor Cam (6 Faces X 60 degrees each = 360 degrees = 1 Revolution).

In the case of Lorrie's MIGHTY 225 Slant Six (which I'm using because it make the arithmetic easy), the Dwell Angle is specified as 40 degrees. This means that there is 10 degrees AFTER a Lobe Peak, and 10 degrees BEFORE the next Lobe Peak on each face where the Points are OPEN, and between those two 10 degree areas, there is a 40 degree space where the Points are CLOSED. This is the Dwell.

The Points are closed twice as long as they are open.

Since the Number One Peak comes around to fire the Number One Cylinder every time the Distributor Cam makes a full revolution, then the Distributor Cam is turning once every time the Engine turns twice, since it takes two revolutions of the Crank Shaft for the Engine's Number One Cylinder to be ready to produce another Power Stroke, and thus NEED a spark.

So at 4,000 RPM, the Distributor is turning 2,000 RPM, which means that the Distributor is turning 720,000 degrees per minute (2,000 RPM X 360 Degrees = 720,000 Degrees), which is 12,000 degrees per second!

So one degree of Distributor Cam Rotation at 2,000 RPM (4,000 RPM Crankshaft Speed) takes 1/12,000 of a second (1.2 milliseconds?), and 40 Degrees of Dwell X 1.2 ms = 48 ms. per each Dwell Period, which is 48/1000th of a second.

The Ignition Coil has to go from discharged to saturated in 48/1000th of a second at 4,000 RPM.

That is what is meant when you say "very fast". AND it would be twice that fast (24/1,000th of a second) at 8,000 RPM, although Lorrie's MIGHTY 225 Slant Six won't turn that fast.

Isn't this fun?

JC
 

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Wow...Wish these conversations..... Dissertations...Tutorials....were taking place out in the shop, with our feet close to the fire and looking at each other. Be much easier to get the points across and everything understood.
The dual-point distributer was devoloped to counter the the diminshed coil saturation time on hi RPM engines. The 2 sets of points are wired in Series. In operation, one set of points opens, then before it closes, the other set of points opens. Thereby keeping that particular coil saturation event in process until the second set of points closes. This isn't the ONLY reason dual points were invented, but was one of the driving factors.
Distributers were re-curved back in the day using one of these:. http://www.glenn-ring.com/bosch/sun_620_640.jpg Some of the good shops probably still have one of these machines, the rest of us have to do it on the engine or in the dyno room.
Using a kit similar to this: Spectre Performance 5754 HEI Distributor Advance Curve Kit GM Vehicles w/HEI Distributors
 
Here are the relevant specifications from the Shop Manual:
CENTRIFUGAL ADVANCE:
@400 RPM .5 - 1.5 Degrees
@500 RPM 3.5 - 4.5 Degrees
@800 RPM 5.75 - 7 Degrees
@1400 RPM 8.25 - 8.5 Degrees
@2000 RPM 10.75 - 12.75 Degrees

VACUUM ADVANCE:
1000 RPM 2 - 5 Degrees @ 8"HG Vacuum
1000 RPM 4 - 7 Degrees @ 10 HG Vacuum
1000 RPM 5.5 - 8.5 Degrees @ 15 HG Vacuum
1000 RPM 5.5 - 8.5 Degrees @ 20 HG Vacuum
I'm not certain if these values are being stated in camshaft or crank degrees. I don't have a FSM or even an old Motors manual handy but they appear ot me to be crank degrees, as read off the harmonic balancer with a timing light.
But notice....These are stated with everything in by 2000RPM, a relitively LOW speed. The vac advance is done at 1000 RPM.
At any given time of engine operation the motor will be using a combination of centrifical and vac advance. The point of any street driven engine settings is to arrive at a compromise of best power and fuel milage without spark knock under load.
Its enough for ME to know what a coil does. I have enough other things I am interested in learning about to spend time and brain cells studying Electricity at the Electron level.
The Condensers purpose is to limit pitting of the points as they open and close. I replace it everytime I install new points.
The Condenser CAN be tested tho with a volt/ohm meter.... Reading the Ohms scale one lead on the wire and one on the base of the condenser a properly funtioning condenser will go to the zero end of the scale and climb to infinity. Reverse the leads and the needle will climb to infinity then drop to zero. A bad condenser will climb to some middle point of the range and/or do nothing.


 
 

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so ... you know a little about sound equipment. do you know what impedance is? this has abearing on all this. the mag field will stop expanding when current stops flowing. a counter electromotive force is created by the mag field induced. when it equals the electromotive force moving the current, flow stops. it's like the more you try to put in the more resistance to putting in occures. the condenser(capacitor) is like an accumulater in hydrolics. sort of a spring loaded can. you can fill it up, but when you open it the contents will spray out. p.s. it's main function is to help the coil mmake a spark. if it is not properly matched to the ign sys. point pitting can occure.[neg metal on the neg contact means not a bigg enough capacitor]
 

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the condenser will charge to over 100v at rpm. when the points open there's 12v on the + side of the coil. 100v on the neg side will cause current to flow back through the coil. this "back flow" is what causes the rapid mag field collaps.
 

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Discussion Starter · #18 ·
Wow...Wish these conversations..... Dissertations...Tutorials....were taking place out in the shop, with our feet close to the fire and looking at each other.
Hey Mr. B&F,
"SHOP"? "FIRE"? Don't I wish! :) "It's Whatcha Do With Whatcha Got" (Kay Starr)

Be much easier to get the points across and everything understood.
Actually, what is happening is that all this is finally coming together in MY head. You guys already KNOW most of this. My writing about it is MY way of making sure that I know about it. Where I'm off, you guys need to say.

The dual-point distributor was developed to counter the diminished coil saturation time on hi RPM engines.
There HAD to be a way to do it. Nicola Tesla was who invented the Ignition System. And that was a LONG time ago. One smart dude, that Tesla.

The 2 sets of points are wired in Series. In operation, one set of points opens, then before it closes, the other set of points opens. Thereby keeping that particular coil saturation event in process until the second set of points closes. This isn't the ONLY reason dual points were invented, but was one of the driving factors.
Are you saying that the Coil Saturation takes place while the Points are OPEN?

Distributers were re-curved back in the day using one of these:

http://www.glenn-ring.com/bosch/sun_620_640.jpg

Some of the good shops probably still have one of these machines, the rest of us have to do it on the engine or in the dyno room. Using a kit similar to this:

Spectre Performance 5754 HEI Distributor Advance Curve Kit GM Vehicles w/HEI Distributors
Am going to have to do some research on Distributor Recurving. Don't think it would be applicable to the 3.14, but it would be nice to know about it.

I'm not certain if these values are being stated in camshaft or crank degrees. I don't have a FSM or even an old Motors manual handy but they appear to me to be crank degrees, as read off the harmonic balancer with a timing light.
From the instructions in the FSM, it speaks of setting the "Test Stand". So don't think it was done with a Timing Light.

But notice....These are stated with everything in by 2000RPM, a relatively LOW speed. The vac advance is done at 1000 RPM.
The FSM doesn't seem to be to "hip" does it? Everything is SO conservative.

At any given time of engine operation the motor will be using a combination of centrifical and vac advance. The point of any street driven engine settings is to arrive at a compromise of best power and fuel milage without spark knock under load.
Well, just got back from running the weekly errands with Ms. American, and have to say that SHE JUST ISN'T RIGHT YET. But at least she doesn't have any "spark knock".

It's enough for ME to know what a coil does. I have enough other things I am interested in learning about to spend time and brain cells studying Electricity at the Electron level.
Started looking at the subject of "condensers". They are also called "capacitors". The explanation started with their invention back in the 1700s!!!

The Condensers purpose is to limit pitting of the points as they open and close. I replace it everytime I install new points.
Right... Plugs, Points, and Condenser... That's a Tune-Up. BUT, about the Condenser limiting "pitting", isn't THAT more of a side-effect? They have a REAL purpose in the working of the Coil/Points/Etc.

The Condenser CAN be tested tho with a volt/ohm meter.... Reading the Ohms scale one lead on the wire and one on the base of the condenser a properly funtioning condenser will go to the zero end of the scale and climb to infinity. Reverse the leads and the needle will climb to infinity then drop to zero. A bad condenser will climb to some middle point of the range and/or do nothing.
As mentioned previously, this is all VERY interesting, and all VERY mysterious.

Anyway, it's cold here today. Supposed to get colder tonight, and rain. Have to cover the Philodendrons, and bring in the Potted Plants. Ms. American is already back under her Plastic&Tarp.

See the Monday Afternoon Update for the latest skinny on Ms. American.

I'll hang in here, if you'll hang in there.

JC
 

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Discussion Starter · #19 ·
so ... you know a little about sound equipment. do you know what impedance is? this has a bearing on all this.
Hey Mr. GZ,
I have a BIG/OLD Concert Sound System. But the way it works is as much a mystery to me as is the Ignition/Carburetor System in the 3.14, and Lorrie's /6!

The mag field will stop expanding when current stops flowing.
Alright.

A counter electromotive force is created by the mag field induced. When it equals the electromotive force moving the current, flow stops.
Can accept that this happens, but do not understand the reason yet.

It's like the more you try to put in the more resistance to putting in occurs. the condenser(capacitor) is like an accumulator in hydraulics. Sort of a spring loaded can. You can fill it up, but when you open it the contents will spray out.

P.S. It's main function is to help the coil make a spark. If it is not properly matched to the ign sys. point pitting can occur. [neg metal on the neg contact means not a big enough capacitor]
All very mysterious! :)

There is just so much to know. More than any ONE person can handle.

JC
 

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Discussion Starter · #20 ·
the condenser will charge to over 100v at rpm. when the points open there's 12v on the + side of the coil. 100v on the neg side will cause current to flow back through the coil. this "back flow" is what causes the rapid mag field collapse.
Hey Mr. GZ,
Is this "back flow" a "neutralizing" of the +'s Magnetic Field?

JC
 
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