New Coil, balast resistor wiring?

[DQ81]

I have searched and seen many topics mentioning the balast resistor. I now get what it does but couldn't find the answer to the following question.

318 w/ electronic ma mopar ignition (is a ballast resistor a must on this setup?)

I replaced all my ignition components today, dizzy, cap/rotor/plugs, MSD wires, Crane Fireball Coil PS20.

Everything runs fine with the stock BR or supplied BR however I want to be sure.

The coil came with a single balast resistor. Two spades L/R. The stock resistor has four spades 2L/2R. It will only run one way with the Crane resistor. It will also run with the stock resistor although seems to give lower, too low, voltage readings. The two + wires have a jumper (left side) so that doesn't seem to matter. What are the other two for no the right, one goes to the coil and the other..?!

I realize I need to run a balast resistor to not go above the desired 8volts to the coil to avoid frying it, however my readings at the coil while running are sporadic at best, in fact all over the place. I have a good ground etc. but I get half second readings of 2 volts, then 6 volts then 15 volts then 5 volts etc.

What's the second wire (thinner one) on the right female plug that goes on the stock balast resistor for? Can I ditch it or jump it without causing any harm?

What voltage should be at the coil, ign. on not running?

What voltage should be at the coil while running?

What do I want to test on my BR and between which spades? Factory or Crane supplied.

many thanks in advance.

 

[DQ81]

After reading up on ignition systems the last 24 hours, methinks me gonna do the HEI conversion... Have most of the stuff on hand and it will eliminate many a thing that can go wrong, let me clean up and replace my wiring AND give me a hotter and better spark...

Found what I needed btw on the balast resistor reading I should be getting...

 

[DQ81]

and this is what convinced me...

http://www.slantsix.org/forum/viewtopic.php?t=15779

which I believe has it's origins

here

 

[dgc333]

If you use the GM HEI module with a conventional coil you will still need the ballast resistor. GM designed a coil for the HEI system that did not require the ballast. To eliminate the ballast you will also need a coil that is designed to run at full battery voltage, the vast majority of the after market canister coils will require a ballast where it is triggered by a mopar ECU or a GM HEI module. Also, a factory GM HEI module when used with a canister type coil will have less rpm range than the stock mopar electronic system. You will need an aftermarket module to see an gains in high rpm performance.

The original mopar electronic system used an external bias resistor to the module hence the 4-pin ballast resistor. These are identifiable by having 5 pins in the connector. The later modules and the performance modules do not require the external bias resistor, only 4-pins in the connector and uses a 2 terminal ballast resistor.

Use tha ballast resistor that is recommended for the coil you are using. MSD has a ballast resistor specific for their Blaster series coils.

 

[DQ81]

If you use the GM HEI module with a conventional coil you will still need the ballast resistor. GM designed a coil for the HEI system that did not require the ballast. To eliminate the ballast you will also need a coil that is designed to run at full battery voltage, the vast majority of the after market canister coils will require a ballast where it is triggered by a mopar ECU or a GM HEI module. Also, a factory GM HEI module when used with a canister type coil will have less rpm range than the stock mopar electronic system. You will need an aftermarket module to see an gains in high rpm performance.

The original mopar electronic system used an external bias resistor to the module hence the 4-pin ballast resistor. These are identifiable by having 5 pins in the connector. The later modules and the performance modules do not require the external bias resistor, only 4-pins in the connector and uses a 2 terminal ballast resistor.

Use tha ballast resistor that is recommended for the coil you are using. MSD has a ballast resistor specific for their Blaster series coils.

Thanks for your response Dave,

I have a ballast resistor that was supplied by Crane for my coil. In addition my coil can run without, it's a 'high performance' coil, comparable with an MSD canister type. Additionally the coils skimpy leaflet does say that a Chrysler style 4 prong balast resistor can also be used.

The problem is it leaves me with one wire too many. It's a 2 spade resistor and I have the (73) 5 pin 4 spade ballast resistor setup. I'd rather used the resistor supplied by the manufacturor of the coil, but how? What to do with the bottom wire that usually hooks up to the 4 pin ballast resistor?

Aditionally I've read the high RPM spark los argument, officially above 6500rpm in practice some claim loss at 4500rpm.

This is a streetmachine that barely see's above 4300rpm, also if I do HEI and don't like it, I can go right back

But if you could help me to get the ballast wiring in order that would be good. In short the question is, how to go from a 4 pin to a 2 pin configuration?

 

[DQ81]

Measured the resistance on both BR's, both factory and Crane Fireball:

Fireball:

2.0 Ohms

Stock:

1.9 Ohm (top)

5.9 Ohm (bottom)

As the Crane and stock resistor are so close I'll just use the stock resitor for now. I'm pretty set on the HEI conversion unless someone wants to convince me otherwise based on experience or facts...

Now here's something that's got me slightly stumped:

Measured the voltage at the + side of the BR (plug with jumper) with the ignition on, engine not running= 11.8 volts (battery reads 12.6) I'm assuming there is some degredation in voltage due to old wiring and perhaps the Alt meter creating a little resistance.

Measure the voltage at the + wire of the coil disconnected from the coil and it reads 11.6 volts (with BR in line of course)

Now, with the + wire connected to the coil I get 5.6 volts (engine off, ign to on) WTF?!

Is this due to the inherant resistance in the coil? Or is the coil sucking up some of the voltage already? Or should it read around 12 volts also?

 

[mopar head]

I believe your readings are normal, Try not to figure why, or you will go insane:read2:

 

[DQ81]

I believe your readings are normal, Try not to figure why, or you will go insane:read2:

Oke, I'd still like to know why the coil + wire gives a lower reading once hooked up though....haha

I'm one of those people who just has to know why...

 

[RedFish]

a resistor limits current flow and creates heat in doing so. With the wire disconnected from the coil the only flow is through the meter leads. Little to no resistance will be seen and no heat will be generated. Once the wire is connected the coil starts storing energy similar to charging a battery.
Probably still doesn't make sense huh ?

 

[DQ81]

a resistor limits current flow and creates heat in doing so. With the wire disconnected from the coil the only flow is through the meter leads. Little to no resistance will be seen and no heat will be generated. Once the wire is connected the coil starts storing energy similar to charging a battery.
Probably still doesn't make sense huh ?

No that makes perfect sense, if you see the coil as a 'dead' battery in a way. So the coil, once connected consumes half of the current.

The pertinent question is, is aprox 6volts of current enough? Should it read more?

I thought 8volts was ideal?

 

[cudaman51]

when the circiut is complete you have a voltage divider.the voltage across the coil and the voltage across the ballast resistor ad up to the battery voltage

 

[dgc333]

Now here's something that's got me slightly stumped:

Measured the voltage at the + side of the BR (plug with jumper) with the ignition on, engine not running= 11.8 volts (battery reads 12.6) I'm assuming there is some degredation in voltage due to old wiring and perhaps the Alt meter creating a little resistance.

Measure the voltage at the + wire of the coil disconnected from the coil and it reads 11.6 volts (with BR in line of course)

Now, with the + wire connected to the coil I get 5.6 volts (engine off, ign to on) WTF?!

Is this due to the inherant resistance in the coil? Or is the coil sucking up some of the voltage already? Or should it read around 12 volts also?

The + side of the BR should measure battery voltage. The difference you are seeing is due to corroded/bad connections/contacts. A max of .5 volts is Ok but you have almost a volt so you should look for the source of the drop.

The + wire of the coil disconnected you do not have any current flowing so you should measure battery voltage, the .2 volts difference from your last reading is not significant and could be attributed to a cheap volt meter that has low input impedance. A volt meter allows a very small amount of current to flow in order to make a measurement. A cheap meter will have a lower resistance that will allow more current to flow resulting in a small drop across the ballast resistor resulting in your .2 volt difference.

The third test with the coil connected you the ignition is now flowing current to ground so you are measuring the voltage drop do to the ballast resistor. The 5.6 volts is normal.

FYI, a ballast resistor by definition is a variable resistor that changes its resistance as the temperature increases. With the key on and engine not running you have a constant flow of current to ground which heats up the resistor increasing its resistance resulting in a lower voltage applied to the + of the coil. With the engine running at idle the current flow is being turned on an off not giving the ballast as much time to heat up so you should see a voltage reading that is a volt or so higher. At very high rpm the voltage will even be higher, it will never be at battery voltage because of the base resistance of the ballast but could be 8 or 9 volts. If you were to run the coil at the higher voltage at low rpm you would over heat the coil and cause premature failure.

Because the output of the coil secondaries is based on the magnetic filed saturation of the windings and the saturation is time dependent the output of the coil goes down as the rpm goes up. Mopar chose to use the variable resistance of a Ballast Resistor to compensate for this by varying the voltage over rpm. Modern inductive ignitions will run the coil at battery voltage but electronically vary the dwell degrees the current is flowing, shorter at low rpms longer at higher rpms to compensate for the drop off.

 

[dgc333]

Thanks for your response Dave,


The problem is it leaves me with one wire too many. It's a 2 spade resistor and I have the (73) 5 pin 4 spade ballast resistor setup. I'd rather used the resistor supplied by the manufacturor of the coil, but how? What to do with the bottom wire that usually hooks up to the 4 pin ballast resistor?

If you are using a performance mopar ecu the extra wire just dead ends in the ecu connector and you don't have to worry about it. Same if you are going to wire in a GM HEI module. That extra wire will not be connected to anything.

You can simply plug one spade of the dual connector on the + side of the BR to the Crane ballast and let the other hang in space. On the other side just connect the spade of the connector with the wire that goes to the coil + (also should have a brown wire on the same terminal) to the other side of the Crane ballast. The other side will just be a piece of wire in the harness that is not connected to anything.

 

[DQ81]

If you are using a performance mopar ecu the extra wire just dead ends in the ecu connector and you don't have to worry about it. Same if you are going to wire in a GM HEI module. That extra wire will not be connected to anything.

You can simply plug one spade of the dual connector on the + side of the BR to the Crane ballast and let the other hang in space. On the other side just connect the spade of the connector with the wire that goes to the coil + (also should have a brown wire on the same terminal) to the other side of the Crane ballast. The other side will just be a piece of wire in the harness that is not connected to anything.

cudaman51 and Redfish, dgc333 thanks a million guys!!

It makes complete sense and now I have a better understanding of my ignition.

As the resistance offered by the crane ballast and the reistance offerd by the stock Mopar ballast is the same measured in ohms (1.9ohms) on an indeed cheapy volt meter. I am sure I can leave the stock Mopar in place (also the crane manual does say a "Chrysler style 4 pin BR can be used)

Due to the variable nature of the signal being sent by the BR, when running does it makes sense that I get sporradic readings at the + terminal on the coil as described above? If I understand you correctly it would make sense as the BR is doing it's work as described right?

Theoretical question for you:

If the ohm reading, resistance, of the Crane ballast were lower, say 1.1ohms or something, that would result in a lower voltage being sent to the coil correct? Or the other way around?

With ohms, the lower the number the higher the resistance correct?

Thanks again!

 

[cudaman51]

if the resistance of the balast resistor is lowerd it will shift more voltage over to the coil. the voltage drop is directly praporshanel to the resistance.

 

[cudaman51]

ohms is a unit of resistance.the more resistance the less current and the more voltage drop. resistance is the oposit of continuity whitch is measured in mhos.

 

[dgc333]

Voltage = Current x Resistance, if you know two you can solve for the third.

Changes in voltage at the + side of the coil should not be sporadic. A few volts change in relation to changes in the rpm can be expected but if you have the voltage jumping around then there is some thing else going on. I'd go back to the bad/corroded connections.