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Mopar recommends running the ballast resister but I know guys that have done as you said with no adverse effects although they usually were not run for long periods when run.

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Ballast resistor bypass will work for an emergency but not for regular use.

Multi spark systems can live without ballast because coils are feeded just when triggered, but on regular ignition systems they are constantly positive feeded from ign switch.

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I by-pass mine with the pertronix points conversion and their flame thrower coil,it has its own resister built in to it

the pertronix conversion needs the full 12 volts to work correctly.

been like that for 15+ yrs now

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I bypassed mine w/ a MSD Blaster 2 and it ran great. Some say it will kill the ECU. I ran mine for hours on end, car running 195 temp constantly, on 90 degree + days with zero issues.

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I bypassed mine w/ a MSD Blaster 2 and it ran great. Some say it will kill the ECU. I ran mine for hours on end, car running 195 temp constantly, on 90 degree + days with zero issues.

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actually it's not 'some' who say you need it, it's Mother Mopar.

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I bypassed mine w/ a MSD Blaster 2 and it ran great. Some say it will kill the ECU. I ran mine for hours on end, car running 195 temp constantly, on 90 degree + days with zero issues.

ECU was flush mounted on the firewall. If it was going to overheat and burn up like is claimed, that would have done it. Just a parts store brand ECU, nothing special.

IMO the system worked a little better. A 12 volt coil will like having 12 volts.

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The Blaster II coil should use a 0.25 Ohm ballast resistor with the Mopar chrome box..

Just my $0.02...

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I'm running a stock (Heavy Duty 12v) coil in my daily '73 Dart without ballast resistor.
If I reconnect the ballast resistor, the car starts to stumble at idle and die when put in Drive. I probably have the wrong resistor, but since I disconnected it everything still seems to work fine.
The coil's temp climbs right along with the engine intake's temp.

Today I decided to install a MSD Blaster 2 coil (also without ballast).
After starting the engine I let it run for a couple of minutes and used my infrared tempgauge and pointed it at the coil... It was already at 130-140F and climbing. I kept the engine idling for awhile to see where the temp would end up at and it went up to around 176F when I called it quits.

To me it's obvious the Blaster coil really needs a ballast resistor when used in a daily driver.


Has anyone ever measured the temp of a coil here?

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i believe the Blaster 2 coil is rated at 45,000 volts. your stock 'heavy duty' is considerably less which would explain the amount of heat generated - more windings.

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Ding Ding..
We have a winner...
The later coils such as the Blaster 2 are capable of handling higher input voltages & current for a longer time..

Just my $0.02....

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I'm running a stock (Heavy Duty 12v) coil in my daily '73 Dart without ballast resistor.
If I reconnect the ballast resistor, the car starts to stumble at idle and die when put in Drive. I probably have the wrong resistor, but since I disconnected it everything still seems to work fine.
The coil's temp climbs right along with the engine intake's temp.

Today I decided to install a MSD Blaster 2 coil (also without ballast).
After starting the engine I let it run for a couple of minutes and used my infrared tempgauge and pointed it at the coil... It was already at 130-140F and climbing. I kept the engine idling for awhile to see where the temp would end up at and it went up to around 176F when I called it quits.

To me it's obvious the Blaster coil really needs a ballast resistor when used in a daily driver.


Has anyone ever measured the temp of a coil here?

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I haven't but tomorrow I will, sounds like a fun and easy experiment.

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Thats why Mopar recommends a 0.25 Ohm ballast resistor for the Blaster 2 when used with a Mopar box...
Keep in mind the major thing that burns out the coil is the current, thats the major purpose of the ballast resistor..

Just my $0.02...

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Ditch the stupid ECU and ballast and put in a MSD 6AL box.

Much better spark.

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I have the MSD6 with the built-in Mopar connector and can switch out in about 5 minutes with my chrome box..
My built 440 runs actually better with the chrome box..

When I run the MSD I change the ballast resistor to one that I put a straight wire in..
Note my chrome box is about 10 years old, maybe they built them better back then..

Just my $0.02..

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The ballast keeps cuts the voltage to the coil. A Blaster 2 can handle 12 volts, as would any 12 volt coil.

The "concern" about not running a ballast is that the transistor in the ECU will heat up and burn out with 12 volts flowing through it. Has nothing to do w/ the coil.

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The ballast resistor serves (2) purposes, it drops the voltage but also prevents higher current to the coil as well. Plus as it heats up its resistance increases which drops the input voltage to coil lowering its output voltage..

The coil is capable to handle the higher voltages for short durations OK but since it typically constructed of hundreds of turns of thin 28 gauge wire, sustained cycles of higher voltage along with the current the coil will fail. Think about much like flashlite batteries, a D cell and an AA or both rated @1.5V but the D cell can hold it voltage capability longer as it has the current reserve..

The coil is a voltage step-up transformer, as the coil overheats its efficiency (output voltage) will drop. The ECU is simply a switch triggered by the distributor pickup that turns the coil on/off..

For an MSD box which does multiple switching is able to fire the coil to a higher voltage as it switches on the coil in shorter sequential intervals so the it doesn't heat up as fast...

Just my $0.02..

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The ballast keeps cuts the voltage to the coil. A Blaster 2 can handle 12 volts, as would any 12 volt coil.

The "concern" about not running a ballast is that the transistor in the ECU will heat up and burn out with 12 volts flowing through it. Has nothing to do w/ the coil.

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The ballast resistor serves (2) purposes, it drops the voltage but also prevents higher current to the coil as well. Plus as it heats up its resistance increases which drops the input voltage to coil lowering its output voltage..

The coil is capable to handle the higher voltages for short durations OK but since it typically constructed of hundreds of turns of thin 28 gauge wire, sustained cycles of higher voltage along with the current the coil will fail. Think about much like flashlite batteries, a D cell and an AA or both rated @1.5V but the D cell can hold it voltage capability longer as it has the current reserve..

The coil is a voltage step-up transformer, as the coil overheats its efficiency (output voltage) will drop. The ECU is simply a switch triggered by the distributor pickup that turns the coil on/off..

For an MSD box which does multiple switching is able to fire the coil to a higher voltage as it switches on the coil in shorter sequential intervals so the it doesn't heat up as fast...

Just my $0.02..

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i'll try my best here at the risk of getting flammed it is my understanding that the ballast has no relationship to the ECU. it is the coil and ballast that must be matched. a 'standard' ECU requires the use of a ballast because there is only one firing of the coil. this makes the amount of time the coil is storing voltage longer and cause the coil to get hot at lower rpms. so, if you are using a standard ECU with an oil filled coil then yes, you need to use the ballast recommended by the coil manufacture. in the case of a Blaster2 i believe the recommendation is a .5. a stock coil i think is a .2. you need to use a .5 with the Blaster because it has way more and smaller windings inside to increase the output and it will burn out. with a multi-spark ECU the ballast is not needed because at low rpms, the unit it causing the coil to fire multiple times and NOT storing it.

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The ignition system consists of matched components, one cannot just start swapping piece for piece and expect reliable performance...

The Blaster coils (#P3690560 or #P4876832/33) uses a 0.25 Ohm ballast resistor (#P2444641) normally used with the Chrome box (#P4120534). The standard Mopar OE coils (#P4120889 or #P02495531) uses a 1 Ohm ballast resistor (#P5206436) used with the Orange box (#P4120505). It is not recommended to mix or match components, the ignition system should work but How well? and How long?..

All of these Mopar part #s were taken from the Mopar 2009 performance catalog.

Just my $0.02...

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And yet MSd advises to use a 0.8 Ohm resistor with their Blaster 2 coils. Now what to do?

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Your choice..
With my MSD box and Blaster coil MSD says to bypass the ballast resistor..
Looks like MSD is advising some confusing info..

A good starting point is to follow the brand's advise..

Just my $0.02...

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And yet MSd advises to use a 0.8 Ohm resistor with their Blaster 2 coils. Now what to do?

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Your choice..
With my MSD box and Blaster coil MSD says to bypass the ballast resistor..
Looks like MSD is advising some confusing info..

A good starting point is to follow the brand's advise..

Just my $0.02...

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The reason that I asked if an ECU can handle a non ballast setup is because when I called FBO and told D that I was using his ECU without a ballast and with a Mallory 12v coil, he said that the ECU will burn up.
This bothers me because I have the manufacturer saying that it will burn up but so far it has not. D knows his ignitions!! I only drive the car about 30-45 minutes at a time so maybe it would on a longer drive.
I am cosidering his new ECU/12v coil and keep my existing items as a backup.

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That is exactly what I have seen. People put out information and real world use doesn't support it. I lean towards some engineer looked at the drawings and thought it "could be an issue". Then everybody has ran with it.

When I discovered the MSD instructions for the coil in my glovebox, I also noted that it said that the coil MUST not be mounted horizontal, unless it is epoxy filled. Mine wasn't and had been mounted horizontal long before I got the car. I left it that way and I'd say it had over 10 years and countless miles on it when it left a couple of months ago. Car left here on a hot day and was driven for at least two hours to the guy's home. I got word a month later he was still very happy with the car. Folklore says that he should be pretty mad

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The reason that I asked if an ECU can handle a non ballast setup is because when I called FBO and told D that I was using his ECU without a ballast and with a Mallory 12v coil, he said that the ECU will burn up.
This bothers me because I have the manufacturer saying that it will burn up but so far it has not. D knows his ignitions!! I only drive the car about 30-45 minutes at a time so maybe it would on a longer drive.
I am cosidering his new ECU/12v coil and keep my existing items as a backup.

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Keep in mind that the brand will take a conservative approach.. The reason is that if something fails people will come back and complain/bad mouth things about their products on the internet..

A short drive of 30-45 minutes is not a real test but take a 2 hour drive down in Phoenix in 112 degree heat,
now guess what the temperature of the ballast resistor is...

IMHO...
The bottom line is that the quality brand ignition parts available today are more capable of handling 12V compared to previous generations.. As long as one avoids the Chinese junker line called P** C**p, or one of the later Orange boxes..

Just my $0.02...

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I'm running a stock (Heavy Duty 12v) coil in my daily '73 Dart without ballast resistor.
If I reconnect the ballast resistor, the car starts to stumble at idle and die when put in Drive. I probably have the wrong resistor, but since I disconnected it everything still seems to work fine.
The coil's temp climbs right along with the engine intake's temp.


Today I decided to install a MSD Blaster 2 coil (also without ballast).
After starting the engine I let it run for a couple of minutes and used my infrared tempgauge and pointed it at the coil... It was already at 130-140F and climbing. I kept the engine idling for awhile to see where the temp would end up at and it went up to around 176F when I called it quits.

To me it's obvious the Blaster coil really needs a ballast resistor when used in a daily driver.


Has anyone ever measured the temp of a coil here?

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I decided to try to run my MP electronic ignition with the BR shorted as an experiment. The BB engine seemed to run better to me. It was smoother and seemed more responsive. I used a IR temp unit to measure the 12V coil's temp and it ranged from 210 on the bottom to 245 at the top. Its mounted on the intake which measured 175. I searched the net, but could not find a spec for coil temps - anybody have a clue on what is considered too hot?

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I'm running a stock (Heavy Duty 12v) coil in my daily '73 Dart without ballast resistor.
If I reconnect the ballast resistor, the car starts to stumble at idle and die when put in Drive. I probably have the wrong resistor, but since I disconnected it everything still seems to work fine.
The coil's temp climbs right along with the engine intake's temp.


Today I decided to install a MSD Blaster 2 coil (also without ballast).
After starting the engine I let it run for a couple of minutes and used my infrared tempgauge and pointed it at the coil... It was already at 130-140F and climbing. I kept the engine idling for awhile to see where the temp would end up at and it went up to around 176F when I called it quits.

To me it's obvious the Blaster coil really needs a ballast resistor when used in a daily driver.


Has anyone ever measured the temp of a coil here?

---

I decided to try to run my MP electronic ignition with the BR shorted as an experiment. The BB engine seemed to run better to me. It was smoother and seemed more responsive. I used a IR temp unit to measure the 12V coil's temp and it ranged from 210 on the bottom to 245 at the top. Its mounted on the intake which measured 175. I searched the net, but could not find a spec for coil temps - anybody have a clue on what is considered too hot?

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I'm running a stock (Heavy Duty 12v) coil in my daily '73 Dart without ballast resistor.
If I reconnect the ballast resistor, the car starts to stumble at idle and die when put in Drive. I probably have the wrong resistor, but since I disconnected it everything still seems to work fine.
The coil's temp climbs right along with the engine intake's temp.


Today I decided to install a MSD Blaster 2 coil (also without ballast).
After starting the engine I let it run for a couple of minutes and used my infrared tempgauge and pointed it at the coil... It was already at 130-140F and climbing. I kept the engine idling for awhile to see where the temp would end up at and it went up to around 176F when I called it quits.

To me it's obvious the Blaster coil really needs a ballast resistor when used in a daily driver.


Has anyone ever measured the temp of a coil here?

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I decided to try to run my MP electronic ignition with the BR shorted as an experiment. The BB engine seemed to run better to me. It was smoother and seemed more responsive. I used a IR temp unit to measure the 12V coil's temp and it ranged from 210 on the bottom to 245 at the top. Its mounted on the intake which measured 175. I searched the net, but could not find a spec for coil temps - anybody have a clue on what is considered too hot?

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Check the temp of the ECU both w/ and w/o the ballast. The ECU is "suppose" to overheat and die shortly w/o a ballast. Nothing has seemed to prove that. The temp gun may shed some light on this.

What coil are you running?

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""I am currently running a 12v coil from Don at FBO.""

Is that the new #HR COIL that he just released?

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I by-pass mine with the pertronix points conversion and their flame thrower coil,it has its own resister built in to it

the pertronix conversion needs the full 12 volts to work correctly.

been like that for 15+ yrs now

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My

If you are running a "full" MSD system fallow there recommendations they put there systems together to run that way.

I opted to run MP Orange Box conversion kit on my tbi swap and wanted to eliminate the BR so I looked into Blaster2 and as stated it a .8 ohm and scrachen recommended the Pertronix Flame-Thrower so I looked it up. Internally regulated, 1.5 ohm with 40,000 volts.

Now my Mopar engines 9th edition says I need 1.25 min. I bought the Part#40011 Flam-Thrower.

The instructions in the box say "1.5 Ohm Coils 8 cyl all applications Remove resistor."

It's up to you but the math adds up for me but look at your system and deiced for yourself because as you can see there are ALLOT of different opinions on this subject and only a little research along with trial and error will tell.

Just my good luck

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Nacho

What did you use to remove the filler on the back of the ceramic resistor? The stuff is as hard as a rock.

Thanks

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Use small side-cuts to break it up. Crimp and then solder a 12g wire in and reassemble..

I run an old 70's Direct Connection dist.(race-tach drive) in my '64 max wedge without a chrome box. I also use the MSD-6 and hide it behind the dash, electronic regulator and the modified ballast.

An old picture but the ignition hasn't changed..

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I'm running a stock (Heavy Duty 12v) coil in my daily '73 Dart without ballast resistor.
If I reconnect the ballast resistor, the car starts to stumble at idle and die when put in Drive. I probably have the wrong resistor, but since I disconnected it everything still seems to work fine.
The coil's temp climbs right along with the engine intake's temp.


Today I decided to install a MSD Blaster 2 coil (also without ballast).
After starting the engine I let it run for a couple of minutes and used my infrared tempgauge and pointed it at the coil... It was already at 130-140F and climbing. I kept the engine idling for awhile to see where the temp would end up at and it went up to around 176F when I called it quits.

To me it's obvious the Blaster coil really needs a ballast resistor when used in a daily driver.


Has anyone ever measured the temp of a coil here?

---

I decided to try to run my MP electronic ignition with the BR shorted as an experiment. The BB engine seemed to run better to me. It was smoother and seemed more responsive. I used a IR temp unit to measure the 12V coil's temp and it ranged from 210 on the bottom to 245 at the top. Its mounted on the intake which measured 175. I searched the net, but could not find a spec for coil temps - anybody have a clue on what is considered too hot?

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I'm now looking locally for a 0,25 Ohm BR to install

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This question has been around for decades in various forms. I'll try to clarify the fog surrounding it.

When cranking an engine, especially at lower temperatures, the starter imposes so much load on the battery that the voltage drops (as low as 8 to 9 volts). This reduced potential (voltage, E), would reduce the ignition system's spark output and make cold starting difficult. In a nutshell, what the factory did was to design the ignition system (breaker points and electronic) to produce full output at this reduced cranking voltage. Then, under normal running conditions, a resistor is used to reduce the voltage to the design point. This is why there's two different ignition wires (and switch terminals), "start" and "run" (or "ign 1" and "ign 2").

Bypassing the ballast resistor will overtax all ignition components: ECU / breaker points and ignition coil), increasing the spark energy (output) while reducing their reliability markedly.

Factory hi-po ECUs ("gold box", etc.) were designed for race use and used lower-resistance ballasts, their internal components and heat sinking were designed for this, still, they were never recommended for street use / idle.

Little, if any, of the above applies to aftermarket ignition systems and/or components. Many are designed to run on full battery potential; they have either internal regulators or dc-to-dc converters. Even with a factory OEM ECU, if your replacement coil has higher internal resistance than the OEM 1.4 to 1.8 ohm value, you might be able to safely reduce the ballast's value.

Do not lose sight of this fact: If there's no misfiring (at any useable RPM) in your present configuration, no ignition system swap or upgrade will increase output. EG: I witnessed a factory engine dyno session (Chrys.) where the subject engine produced over 150 HP/L on dead-stock wasted-spark ignition (even wires, coil, etc.). All aftermarket systems tried produced zero gains.

Hope this helps,

Rick E.

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This question has been around for decades in various forms. I'll try to clarify the fog surrounding it.

When cranking an engine, especially at lower temperatures, the starter imposes so much load on the battery that the voltage drops (as low as 8 to 9 volts). This reduced potential (voltage, E), would reduce the ignition system's spark output and make cold starting difficult. In a nutshell, what the factory did was to design the ignition system (breaker points and electronic) to produce full output at this reduced cranking voltage. Then, under normal running conditions, a resistor is used to reduce the voltage to the design point. This is why there's two different ignition wires (and switch terminals), "start" and "run" (or "ign 1" and "ign 2").

Bypassing the ballast resistor will overtax all ignition components: ECU / breaker points and ignition coil), increasing the spark energy (output) while reducing their reliability markedly.

Factory hi-po ECUs ("gold box", etc.) were designed for race use and used lower-resistance ballasts, their internal components and heat sinking were designed for this, still, they were never recommended for street use / idle.

Little, if any, of the above applies to aftermarket ignition systems and/or components. Many are designed to run on full battery potential; they have either internal regulators or dc-to-dc converters. Even with a factory OEM ECU, if your replacement coil has higher internal resistance than the OEM 1.4 to 1.8 ohm value, you might be able to safely reduce the ballast's value.

Do not lose sight of this fact: If there's no misfiring (at any useable RPM) in your present configuration, no ignition system swap or upgrade will increase output. EG: I witnessed a factory engine dyno session (Chrys.) where the subject engine produced over 150 HP/L on dead-stock wasted-spark ignition (even wires, coil, etc.). All aftermarket systems tried produced zero gains.

Hope this helps,

Rick E.

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There are two other things that a ballast resistor does:
First, it limits current in the circuit protecting the coil and other components in series with it.
The second is more obscure but just as important. It dampens the "ringing" in the coil when it fires. When the magnetic field collapses in the secondary firing the plug, eddy currents from the secondary are induced into the primary which in turn goes back into the secondary again, at a much lower level but still there and measurable. Meanwhile, the distributor has moved away from that plug wire and the voltage has no where to go but be dissipated in heat, mainly in the coil unless the ballast resistor takes some of it. The ballast resistor is also a damper resistor to keep the ringing to a minimum. The bypass capacitor on the coils positive terminal also aids in stopping the ringing but more importantly filters the energy dissipation to lower radio frequency interference.

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