Ballast Resistor

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dibbons

dibbons

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From the 1965 Plymouth Factory Service Manual page(s) 8-50 and 8-59:

The ballast resistor is a compensating resistance in the ignition primary circuit. During low speed operation, when the primary circuit current flow is as high, the ballast resistor temperature rises, increasing the resistance. This reduces the current flow, thereby prolonging ignition contact life. At high speed operation, when the primary current flow is low, the ballast resistance cools off allowing more current flow, which is required for high speed operation. During starter operation, the ballast resistor is bypassed, allowing full battery voltage to ignition primary circuit.
 
......And your point is? ........ The definition of ANY electrical ballast is pretty much that........it stabilizes current/ voltage/ power going to a load. In the "vacuum tube" days there were various ballast 'tubes' for various purposes

Just like ballast in a boat/ submarine it stabilizes "the vessel."

But that is not it's ONLY purpose. When you crank the engine for starting, especially in "the old days" "in the cold" "in the winter" and when the battery might be a bit down, obviously the old style "wound field" starters drew more current than the newer PM starters. Before the advent and popularity of multi-weight engine oils, that could be a factor. So when cranking, battery voltage goes quite low

If you just ran a 12V coil off the battery with no ballast, it would "see" greatly reduced power during cold cranking

SO THE BALLAST RESISTOR SYSTEM is bypassed during cranking and supplies "full" battery voltage to the coil which gives you a much hotter starting spark.

IMG_0045%20(Medium)-1024x768.jpg
 
The reason the ballast doesn't do as much as RPM's increase, is that the number of spark events becomes closer together as RPM's rise, and when this occurs, less time in micro-seconds for the coil to charge, the points see far less current loading. This is why things like an HEI, other electronic systems use far more current at idle and lower RPM's, and a lot less at upper RPM's. On one of my HEI systems, loading on idle is 4 to 4.5 amperes, at 3K and higher, load lowers to 1.25 to 1.50 amperes. Reason: higher RPM'S do not have the charge time between firing events for the coil, lower load, lower amperes used.

This is why we designed the HEI as what it is, an electronic system that allows the coil to saturate more than other electronic systems, for more fire power at higher
RPM's, but, HEI is NOT a race system, it was designed strictly as a 4K RPM limit higher output system to match leaner fuel/air curves, FOR EMISSIONS USE ONLY, nothing else. They ain't race ignition systems.

If you want to do a race system, Capacitor Discharge is the way to go. CD's don't charge the coil with current for each firing event, the capacitor charges, then tells the cold, uncharged coil to "make spark now, 40 K output", then goes on to the next firing event, does it all over again.
 
Advanced ignition systems using a micro controller to predict dwell, and active current limit, are better than ballast or HEI. While HEI has integrated current limit, dwell prediction is primitive analog circuitry.

A coil on plug ignition can be superior to a CDI, much more reliable.
 
KitCarlson said:
... A coil on plug ignition can be superior to a CDI, much more reliable.
Click to expand...
Yes, because each cylinder then has a dedicated coil, allowing more time to "charge up" between sparks. Actually, magnetic field energy, but "mag up" isn't a term. But, to use a COP system requires a crankshaft trigger plus camshaft sensor if you don't want 2 cylinders sharing a coil ("wasted spark" system). Many fit a 36-1 toothed crank wheel to drive a Ford EDIS (1990's). Better are the integrated coil-driver from a GM LS engine, but I don't know of any off-the-shelf system to trigger one (Mega-jolt?). The megasquirt site has much info.
 
Some COP coils are lower inductance and resistance for quick charge. They achieve a higher peak current. Energy increases by current squared. Mult-strike is possible, and overlap of coil charge is not necessary for most applications. A distributor with two sensors is a simple alternative to crank/cam sensing.
More info here in old post.
COP Ignition Development
 
Yes, well, when I was directly involved with the initial development of the GM HEI, we did not design the system to be a performance system, it was to build a 50K mile, low to no maintenance, consistently higher output ignition system to fire extended spark plug gaps over points system output levels.

YES, I worked directly for Zora Arkus-Duntov in Skunk Works, and was sent to help the High Energy Ignition program design and development.

The reason for the wider gaps, as EMISSIONS settings for more and more strict, l4ess fuel molecules were present in the mixture, and they stayed farther apart, so, lighting them off became more critical as to spark plug gaps. The HEI was not, is not, and never will be a performance ignition system, but does work well on GM crate engines, including their performance series ZZ units.

One fallacy about HEi and other ignition systems, such as MSD CD systems is that morons within the ignition system world insist spark plug gaps be jacked to the moon, that this helps. IT DOES NOT, maximum spark plug gap with both HEI, and MSD CD is set at .045, NO LARGER. During further development of the then new HEI, we began to see module failures caused by slow coil failure changing module load. MANY new cars left Pontiac, Olds and Buick deale5rs, only to have module failures a week later. We determined that the engineers at those 3 divisions were leaning out the mixtures for emissions even further, and opening up the spark plug gaps even further, to first, .060, then, worse, to .080. The added gap caused the epoxy filled coils in cap to overheat, as epoxy does not bleed off heat, to the point the modules were overworked seriously, to failure. The warranty fix was simple, replace the module and coil, reset the spark plug gaps back down to the engineering spec of .045 maximum, fixed the issues.

Today, we see and hear of numerous module failures on coil in cap HEI caused by coils slowly failing, with the explanation "That HEI module just failed, FOR NO APPARENT REASON". Well, NOTHING fails "for no apparent reason", there is a reason for failure for everything, including HEI module failures. There are kits for GM to move the coil off the large HEI cap, use a round, oil filled coil, that stops the module problems with the HEI for GM people.

Look at my avatar, no coil in cap, it is round, oil filled, and remote mounted from the distributor. That is the way it should be. We designed the HEI to be one unit, no off body parts, which made for NO oil filled coils, that was a serious mistake. Good that MOPAR cannot have the coil in the cap, that is a solid benefit.

Over work any ignition module, and it will fail, including MSD ignition boxes caused by 70 percent Blaster coil failure when those coil's production was moved, in 2003, from Andover, Indiana, to just across the Rio Grande, to Pro-Bobbin, in Juarez, Mexico.

So, the HEI is not a performance ignition, but, not so great engineers have over hype advertised them as the end all ignition system that they are not. So, if you go with any sort of HEI for a MOPAR setup, good, just use a round, oil filled coil, good plug wires, and no larger than .045 spark plug gap, NO MATTER WHAT THE SALES BS SAYS.

As far as one coil per spark plug sysems, complicated, great, but not practical for everybody.
 
All the moaning I have heard over Uni-Lite failures stems from people NOT running the system correctly is amazing. I never saw Boots Mallory ever run any Uni-Lite without correct ballast resistance. All that came about after Boots died, and some know it all "engineer" spewed that "take that resistor out, it'll make the system produce 80 billion spark plug volts". All I ever saw doing so to do, murder the Uni-Lite modules. SAME occurs with today's default electronic sets of points, PerTronix Ignitor.

Way too many 'educated engineer' morons bleat and yell to remove all ballast resistors from the U-L, which will increase spark output. There never has been a U-L that was designed to work witu0out a ballast resistor, and, in fact, there is need for more than stock OEM resistance. So much for all the over hype sales ads.

Not many people are aware Boots developed his systems to use OEM MOPAR parts, like vacuum advances, rotors, caps and points. One of those items was the Mallory ballast resistor, 0.60 ohms, straight from a MOPAR. It was designed to work with the stock vehicle resistor, in line. This kept the U-L alive. I have recommended to a lot of people they use both the stock ballast resistor AND the Mallory/MOPAR, and their U-L failures and issues go away.

I have many people running stock U-L Mallory, with stock MOPAR resistor, Mallory resistor, stock MOPAR coil, 7, or 8 mm magnetic suppression spiral core plug wires, and spark plug gaps @ .035 maximum, with no problems. I'd rather have a Uni-Lite electronic points unit, than any and all PerTronix disasters. sorry, this from all the Ignitors I have replaced, 5 - 55 gallon barrels of them in decades of conversions, all dead on arrival.

Opinionated? NO, just been there, in person, and fixed them.
 
U-L has been reliable, I do use a ballast. If it ever fails I have plan make a trigger module using coil driver IGBT, and active current, like my other ignition use.

Keeping on topic:
I have considered designing and electronic ballast with IGBT and microcontroller. It would be same size as stock ballast, but have many features. It would current limit, properly control dwell, and have auto shutdown for key-On with stalled engine. Those features are in present in my ignitions. Raw parts cost about $10.
 
As far as your efforts to build a better mouse trap, most people are far past even U-L systems, but, for them, no matter what some engineer says, do both stock and Mallory (MOPAR) resistors, there is NO loss in spark efficiency, nor output. U-L is a simple electronic set of points, same as PerTronix is, neither can be made to be a hot rod performance ignition system. This is what so many people just can't get over, systems like PerTronix are NOT an HEI, cannot be "over driven" to be one, they are electronic points systems, accept it.

When Boots and I had conversations about the U-L, he said the things were designed to use between 9.5, down to 6.5 volts on a distributor machine, and had no difference from that when used on a 12 volt system with proper ballast resistance. The place they suffer is when people over drive them, no resistors, giant plug gaps, steel/copper wires, billion volt input feeds, whooptie-doo performance coils. They are an electronic set of points, live with it.

I'd think if you were going to all that trouble just for a resistor, you'd be better off just building a better module, with resistor inside, or designed for full, unresisted voltage.
 
Mr. Ray refers to people who have different views than him as 'morons'. He has been chased off a few forums because of his views & disinformation.
Disinformation such as using oil filled canister coils. Transformer oil has veeery poor heat shedding properties, one of the worst for liquids [ 0.13 v 1.00 for water ]. It's benefit is it's high dielectric strength. In contrast, epoxy dissipates heat 3-5 times faster TO.....which is probably one of the reasons it is used in modern coils. The cooler the coil runs, the lower the resistance of the windings & less looses.
A canister coil is the last coil you should use in your hot rod because of it's high leakage inductance & poor magnetic coupling. Both result in reduced spark energy. Transformer coils fitted to modern cars cost more to make than canister coils, so there must be a good reason why car makers spend the extra $$$........

The most informative info on ign I have found is on the website below by Dr. Holden. On the intro page, you will see at the start of the second line 'MDI ign v CDI ign'. Click on that, 73 pages. www.worldphaco.net
 
Wow, "Bewy", not enough personal integrity to post under his own name. Just one of those persons that hangs out at websites and causes trouble for those that are actually helping.

Now, oil vs epoxy, lets take a closer look.

"Bewy" has stated, or, copy and pasted that epoxy coils run more heat transfer out of the core windings than oil filled coils. Very interesting. Now, lets stop the copy and paste idiocy, and take a "hands on" look, shall we.

First to know, epoxy is not a heat leaching mixture, unless you are on the Space Shuttle. Only ONE epoxy blend has a 2.0 percent heat transfer rate. There are coil manufacturers that state they have heat leaching epoxy ijn thier coils. Realize 5that the Space Shuttle epoxy was only used in ONE application, and cost a paltry 100K PER OUNCE. So, the next time "Bewy" tells you that the $20.00 epoxy filled coil has that same epoxy in it, realize that the coil should actually cost much more than 20 bucks, and...doesn't.

Ever see a heat plate under a carb, designed to keep heat in the manifold, NOT the carb? Well, it IS NOT OIL, IT IS EPOXY. This makes the manifold metal heat travel back into the manifold, NOT the carb.

Then, we have coils, oil filled, and epoxy.

Anyone ever tough a coil that was running on an engine, to see how hot it was? I'd bet that when you did this, the oil filled coil was considerably hotter than the epoxy filled coil.

Oh, Dave, you are lying to all of us. Not if you have ever temp tested a running coil with your hand. WHY? As stated, epoxy does not leach heat, it encapsulates it, into itself. And, as we are all aware, the heat created inside a coil is done from the windings, which are centered in the coil body. Epoxy fills and insulates the windings, and the coil body feels cooler to the touch. Now, oil, those coils feel so hot to the touch, why????? Well, ever hear of "Thermo-Siphoning"? Well that was done to engines beflre water pumps were in play. It is the engine heating the cooling media, to a boil, then, rising the coolant up into the top of the radiator, down the core, cooling, then, drawn back into the engine to do it all over again. THAT is what an oil filled coil does, thermo-siphon, and the reason those oil filled coils feel so hot to the touch, they are removing heat from the core windings to the body.

One fact, GM large coil in cap HEI, ever see posts about the HEI modules being junk, "failed for no reason"? HEI modules NEVER 'fail for no reason". 99.75 percent of continuing HEI module failures are caused by the in capo epoxy filled coils overheating their internal windings, progressively. As the coils get worse, they still work, but put more load on the modules, to module failure. The fix that stops module failures is changing the in cap coil, or, a better option, change the coil out of the cap, to an oil filled round coil next to the distributor. Proven fact, this stops module failures and coil failures in their tracks. Ever wonder just why large HEI's had oil filled coils, when everything else GM used oil filled round coils? Well, it was safety. Oil is combustible, burns, can explode. So, a coil with a delivery terminal, in the top of the cap, under the rotor, with a clear path down the carbon button, to the area the rotor is in, onto the rotor, then, flung out to the spark gap between rotor tip and cap terminal, BOOM, explosion under the cap, or, worse, blow the cap apart, burn down the whole car. Later HEI's used a remote mounted epoxy coil, doesn't have the possibility of a nuclear blast under the hood.

Also, I was "removed" from a couple of web sites, by people like "Bewy", they just didn't like opposition to my facts and truth. Notice that I am not now, prohibited from posting from am=ny website, and in fact, those two sites asked me back when they found out the other person(s) weren't as honest as they purported to be.

So, I will leave it, and here at that, go do the hand tests on your own, make your own findings, and, decisions, which is something "Bewy" really doesn't want you to do, it'll ruin his whole day, and act.

Get the facts for yourselves, not "Bewy" copy and paste.
 
My name is Geoff. Not hiding from anyone or anything. When I attempted to join this great forum, Geoff was taken....so I used my nickname.
Dave, you were caught out [ not be me, others ] on maxperformanceinc.com providing 'information' that was shown to be incorrect. That is a forum that I visit daily & you have not posted there for months.
Heat conductivity of insulators. The info I provided is readily available on the net or in engineering handbooks. I got it from the Bosch Automotive handbook, 9th edition, 1543 pages. The same book says this, about ign coils: "The windings must have good electrical insulation to prevent electrical discharge & flashovers either to the inside or to the outside. For this purpose, the windings are usually cast in epoxy resin in the ign coil housing."

The metal case of a canister coil is going to feel 'hot'! The metal case, relatively speaking, is a good conductor of heat. The coil is being heated internally during operation & is also absorbing under-hood heat. Of course it will feel hot!
One thing I do agree 100% with D. Ray on is the use/benefit of manifold sourced vac adv.
 
so now we have two newbie's with under 20 posts bringing their little cat fight to this board? really? grow up guys and take that bullshit to where ever it started.
 
If you upgrade to a modern ignition, you can pitch the ballast resistor for a flux capacitor...
 
In more detail. IGBT switches ignition coil, sense resistor monitors coil current, BJT pinches off IGBT to regulate current, microcontroller predicts "just in time" trigger of IGBT, based on RPM, desired timing ....
 
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