Need for early condensers?

[flatheadmurre]

Originally Posted by JSeery

There is more to this than protecting the points. The condenser and the coil form an LC circuit.

"The LC circuit produces a damped, oscillating current which bounces energy between the capacitor’s electric field and the ignition coil’s magnetic field. The oscillating current in the coil’s primary produces an oscillating magnetic field in the coil. This extends the high voltage pulse at the output of the secondary windings. This continues beyond the time of the initial field collapse pulse. The oscillation continues until the circuit’s energy is consumed."

These systems (circuits) are designed to meet specific criteria. You can get an ignition system to work with odds and ends components, but that doesn't make it a well designed system. Is it a major concern on an early Ford car? Guess everyone needs to decide where the trade off is between good enough and better. But, these ignitions were originally designed with the better in mind.

What you call bouncing is usually refered to as ringing dealing with transformers and is something we really don´t need or desire...we would like an instant transformation of the magnetic energy to a spark...the ringing eats up some energy since like all systems there is resistance involved here to converting energy to heat.
Think of a breakerless system where there is no condensor just a solidstate part operating like a lightning fast set of points...letting all the magnetic energy in the coil go to the plugs at once...is that a less good performing ignition ?
Main reason the condensor is there is to keep voltage down under the level where glowdisharge starts which turns into arcing.
Condensor has to be large enough to store the energy over the points until the gap is large enough to prevent arcing itself.
Arcing would use up some of the energy stored in the coil and give you a weaker spark.
Is there ringing in the system...of course...but it´s not a goal we designed for it came with the package...

[philipswanson]

Never had a problem with plain old Napa Echelin condensers for my '40 or shoeboxes. Been running them for 50 years! Don't know what all the fuss is about.

[Terry,OH]

I believe this posting started about the early style 33-36 condenser which is not offer by NAPA. One of the posters here is thinking about the need for the early condenser and this posting has morphed into the Spec. of the condensers, since all the V8 condensers prior to the war have the same electrical Spec.

[JSeery]

Agreed, and that would be the spec's I would be looking for in a reproduction.

[rotorwrench]

The coils changed at least 4 times during the evolution of the helmet type distributor production. It's hard to say how many other designs were tried during that period. They were all a bit different and certainly different than the can type coils. The back flow of energy from the collapsing field was what they were trying to control the best they knew how. The amount of back flow energy is what they chose the capacity of the condenser to meet. While other condenser capacities will work, they wanted to tune it to the system for best efficiency or at least as good as they could get it.

Anyone designing a cap to work needs to do the same thing. I always wondered if those guys had an oscilloscope. Those things were just starting to become a tool after 1931 so it was relatively new technology back then.

[tubman]

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Originally Posted by JSeery

Agreed, and that would be the spec's I would be looking for in a reproduction.

I am curious what your reason for this would be. This is not to cause any conflict, but to find out what is actually needed and why. These does seem to be a void out there that needs to be filled.

[flatheadmurre]

The design of an ignition system has many variables...and most of us don´t have getting the car started at subzero as one today...
My thinking is aiming for optimum at cruise speed would be just fine.
And i have and can actually measure what happens so not just guessing..
You have to excuse the mess...i call it creative chaos

[rotorwrench]

The scopes will definitely show it. Sun used them on their later automotive engine analyzer sets so a person could verify how it was working in actual operation.

[tubman]

I guess I must be a little dense; Measure what? Show what? I am sure that you guys will get some readings from your impressive electronic gear, but what do you get and what does it mean? What does the scope show? Are there ranges that define acceptable and not acceptable? Can we put some numbers to this? Is there a direct correlation between the number on the scope and material transfer on the points?

I'm not trying to be "smart" here, but from my experience, just about any engine will run just fine with a large range of capacitance values. The variable must be point life. How does the reading on a scope give us an indication of how the material transference will occur and to what extent?

You two gentlemen are among those whose knowledge and opinions I most respect on this board, so please take this for what it is; a sincere quest for relevant information that I can use in further product development.

"Murre" - Simply put, could you put a helmet distributor with a rebuilt "Skip" coil and one of my .22 micro-farad condensers on that very impressive array of equipment you show and be able to tell me that it is X nano-farads short or long? Or just that the pattern "looks good" or doesn't?

[V8COOPMAN]

Originally Posted by tubman

I guess I must be a little dense; Measure what? Show what? I am sure that you guys will get some readings from your impressive electronic gear, but what do you get and what does it mean? What does the scope show? Are there ranges that define acceptable and not acceptable? Can we put some numbers to this? Is there a direct correlation between the number on the scope and material transfer on the points?

I'm not trying to be "smart" here, but from my experience, just about any engine will run just fine with a large range of capacitance values. The variable must be point life. How does the reading on a scope give us an indication of how the material transference will occur and to what extent?

You two gentlemen are among those whose knowledge and opinions I most respect on this board, so please take this for what it is; a sincere quest for relevant information that I can use in further product development.

"Murre" - Simply put, could you put a helmet distributor with a rebuilt "Skip" coil and one of my .22 micro-farad condensers on that very impressive array of equipment you show and be able to tell me that it is X nano-farads short or long? Or just that the pattern "looks good" or doesn't?

Ha.....Like the Judge in "My Cousin Vinny" said...…"I'd like to know the answer to that one, too!" DD

[35fordtn]

In my opinion there is not a base line sample for a scope test. We used a snap on scope when I work at the GM dealer, but every car was the same. Nowadays we run different compression ratios spark plugs skip coil, vs original coil , etc etc etc. sure the graphs are neat to see the coil charge and discharge and the burn rates, but that’s just it, it’s neat to see. We have nothing relavant to compare to.

For example Jim plans to use a 60hp for these tests. It will have a different burn rate that a 85, however the coil charge and discharge should be the same.

[tubman]

Michael, I still need a distributor/coil, I'm just waiting to get back to you until this thread runs it's course. I'm kinda hoping someone can put some definite numbers on this.

[Terry,OH]

For the electrical Tech.:
https://sites.fas.harvard.edu/~scphy...E1b/E1b_3b.pdf

[tubman]

Excellent read, Terry. Two things have become apparent to me. The first is that the capacitance in the circuit is a function of the characteristics of the coil, while the second is that an ideal capacitance can be calculated, given one can know (or calculate) several esoteric characteristics of said coil. Therefore, it appears to me that unless all coils are made identically, each individual type would be optimally served by it's own special capacitance level. In theory, this would be an expensive and time consuming exercise, meaning that most commercially available condensers are a compromise to be able to serve in a variety of situations. It appears we are fortunate that ignitions will operate over a wide variety of capacitances. I find it interesting that the cited tome concentrates on maximum voltages, with no mention of material transference or point wear. I have no knowledge of how maximum voltage relates to this, but would not be surprised that the two might be directly related, requiring further compromise in the practical ideal capacitance in the circuit, to balance point life and performance.

At this time, I am not able to to do the required research to come up with the desired capacitance for the condensers I build. What I have to do is rely on the work done by the multitudes of ignition component manufacturers out there. Just about every commercially available condenser today is in the mid .20 micro-farad range. I have to believe this is because the engineers at those companies have done the required work with the resonance characteristics of currently available coils and have settled on this, which is good enough for me. While it may seem to leave the old Ford coil group out in the cold, I believe that there is enough tolerance in the resonance characteristics of the systems to tolerate the slight difference in capacitance that is more than overcome by the reliability of the current unit.

Earlier in this thread, a member posed the question of whether a "Skip's Coil" would require the older higher capacitance condenser or would be better with the lower value. This is a good question. Does he just rewind the coils using original type materials to the original specs or has he incorporated some modern technology into his process? If the latter, the newer, lower capacitance condensers may be a better choice. Too bad (for us) he doesn't get involved with these boards. It would be interesting to hear what he has to say.

I am still looking for a mid-30's micro-farad capacitor for you early Ford guys, but I haven't found an acceptable candidate yet.

[rotorwrench]

Originally Posted by 35fordtn

In my opinion there is not a base line sample for a scope test. We used a snap on scope when I work at the GM dealer, but every car was the same.

The check runs of any automotive ignition systems that are designed to peak efficiency will all look about the same on a scope unless something is wrong. It only takes a quick check to see if all is well or no.

Peak voltages will vary with coil winding ratio differences.

The educational study link describes it all and a basic way to calculate a capacitor value for any individual coil design. A person can try the two most prevalent values Ford used on an existing early Ford system and see what the difference might be. Even though Skip rebuilds the coils with his own materials, I would imaging that he still uses the same number of turns of the two windings as Ford designed them to have. The insulating material shouldn't effect any noticeable change in the induction process.

Modern equipment use gets away from the old cathode ray tube type scopes and uses more of a lap top technology. The peak spike voltage shows the start of the ignition event and the burn shows the actual energy release at the spark plug and tells you how the capacitor does its job by the length of burn and how stable it is. This link explains it somewhat. https://www.tomorrowstechnician.com/...g-diagnostics/ Even the oscillation pattern at the end has some meaning as to the function of the capacitor in the circuit.

Since scopes weren't in common use back then, a person has to set up their own baseline depending on what they have to work with. The engine should have good compression or at least consistent compression readings between cylinders and components in good working order.

[35fordtn]

Originally Posted by tubman

Michael, I still need a distributor/coil, I'm just waiting to get back to you until this thread runs it's course. I'm kinda hoping someone can put some definite numbers on this.

You say when and I'll send whatever you need. I am sure we will all (especially me) learn something new by the end of this.

[34fordy]

[QUOTE=

Even though Skip rebuilds the coils with his own materials, I would imaging that he still uses the same number of turns of the two windings as Ford designed them to have. The insulating material shouldn't effect any noticeable change in the induction process.[/QUOTE]

I have a Skip rebuilt Ford coil that I have never mounted that I keep for a spare. I also have 3 other coils, 2 that are used and presumed good, and 1 older USA that is NOS. I have a Perry-Davis condenser/coil tester. I wonder if the PD tester would show any difference between these various coils and if so what would it mean? If anything?

[34fordy]

[QUOTE=tubman;

I am still looking for a mid-30's micro-farad capacitor for you early Ford guys, but I haven't found an acceptable candidate yet.[/QUOTE]

Does this mean you are looking for a supplier of an appropriate capacitor that will fit into your "Trash Can"? Or is it that the materials to build the mid .30's capacitor are not available?

[rotorwrench]

Modern materials for capacitors are superior to what was used in the 1930s. A lot of the really old stuff has likely deteriorated by now. It's basically the microfarad value that is important. Early ones had a bit higher value than the later ones after the war. Ford went back to the can type coils in the 8BA era. If the old original coils still work, they should work as well as Skips rebuilds unless they have gone bad for one reason or another. Skip's will last longer due to better materials but the function should be the same unless he changed the internal design.

[BUBBAS IGNITION]

I love and use skips coils and suggest we all do .

I dont believe skips rewinds anything , i feel as if he has sourced a good coil winding and bobbin , cleans up the old coil (throws the windings and laminate away) and inserts his known good new one ......