This article says no to the ballast resistor if you don't have points.
https://www.hotrod.com/articles/mopp-1110-ballast-resistor-guide-ballast-blast-off/
My Direct Connection instructions from the 80's say to use one, no mention at all of not using one. :alan2cents:
Quote from: dodj on September 10, 2020, 07:43:28 PM
Quote from: Scooter on September 10, 2020, 04:29:03 PM
Their kit bypasses the coil.
You sure about that?
Ok.. bypasses the resistor... kinda hard to get around having a coil in there somewhere. :))
It depends entirely which ignition box you have. If you have the FBO unit or the Petronix unit, you bypass the ballast resistor with a jumper wire. Orange boxes must have it. I use the FBO system. They are much better and I like not using the resistor. They go out all the time.
Yes the ECU gets 12v, but that is for turning it on.
I've never really looked into it but......The ECU controls making and breaking the coil cct. The resistor is part of the coil cct. Stands to reason it will have an effect on the ECU switching transistor.
:alan2cents:
I ran a chrome box and a orange for a while without a resistor. I kept losing coils and I tried various brands. I put a resister back in the system and have been reliable for 2 years now. So my guess is that it's hard on the coil and not the box. :alan2cents:
I'm pretty sure this is how it works.....The dual ballast resistors use one side to send reduced power to the coil. The other side sends reduced power to the original "5" pin ECU. The single ballasts are used with the "4" pin ECU. The "4" pin ECUs take a full 12v and reduce it internally. If you are running a "4" pin ECU and you are using a coil that is designed to take a full 12v, then you don't need to run a ballast. Someone can correct me if I'm wrong.
Quote from: Dakota on September 10, 2020, 05:33:21 PM
This article says no to the ballast resistor if you don't have points.
https://www.hotrod.com/articles/mopp-1110-ballast-resistor-guide-ballast-blast-off/
If this was true, why would the factory electronic ignition introduced in 1972 still use a ballast resistor? If the factory used a ballast resistor with a
stock style ECU, I would do the same. :alan2cents:
I believe Burdar has it right... OE 5-pin ECUs needed the ballast but the later 4-pin units are internally regulated as illustrated by the diagram below which shows the Blue wire going directly to the ECU.. This is the diagram from the electronic update kits which shipped with a single ballast. Note the text at the top about not needing ballast for aftermarket coil.....
(https://lh6.googleusercontent.com/-84nY8AE31FE/UQC2XZwwuOI/AAAAAAAABeM/Kh3tESur0Uk/s640/photo.JPG)
Quote from: DeathProofCuda on September 11, 2020, 08:11:49 AM
Quote from: Dakota on September 10, 2020, 05:33:21 PM
This article says no to the ballast resistor if you don't have points.
https://www.hotrod.com/articles/mopp-1110-ballast-resistor-guide-ballast-blast-off/
If this was true, why would the factory electronic ignition introduced in 1972 still use a ballast resistor? If the factory used a ballast resistor with a stock style ECU, I would do the same. :alan2cents:
I believe the ballast was there to protect the older oil filled coils from the full 12v... they simply could not handle it.
My 74 has the single ballast and a 4-pin chrome box, using the same Petronix coil the FBO kit comes with.
Based on info above and a few wiring diagrams I've reviewed, I believe it's safe for 4-pin ECU to bypass the ballast as long as the coil is up to it.
Happy to be the crash test dummy here... if my ECU burns up I'll be sure to report back.
Thanks for the replies and info guys!
:twothumbsup:
Maybe I can't see the entire photo, but it looks to me like it says that you should use a ballast resistor that is recommended for your after-market or HP coil.
I have the FBO box and petronix coil. Been using it for about 2 years and have the ballast bypassed .
No problems yet.
I will add the 1st coil only lasted a week, but it was said to be defective, who knows. But like I said 2 years, no problems.
Quote from: Fern on September 11, 2020, 01:37:48 PM
I have the FBO box and petronix coil. Been using it for about 2 years and have the ballast bypassed .
No problems yet.
I will add the 1st coil only lasted a week, but it was said to be defective, who knows. But like I said 2 years, no problems.
3 years plus running the FBO box, coil and custom curved distributor on the wife's car.
No issues but I believe the FBO box is designed to bypass the ballast.
My 20 plus year old chrome box ECU, coil, ballast and MP distributor are also running perfectly on my Challenger. I have thought of changing out the chrome box and bypassing the ballast but if it ain't broke.....
Quote from: Scooter on September 11, 2020, 01:27:46 PM
Quote from: DeathProofCuda on September 11, 2020, 08:11:49 AM
Quote from: Dakota on September 10, 2020, 05:33:21 PM
This article says no to the ballast resistor if you don't have points.
https://www.hotrod.com/articles/mopp-1110-ballast-resistor-guide-ballast-blast-off/
If this was true, why would the factory electronic ignition introduced in 1972 still use a ballast resistor? If the factory used a ballast resistor with a stock style ECU, I would do the same. :alan2cents:
I believe the ballast was there to protect the older oil filled coils from the full 12v... they simply could not handle it.
My 74 has the single ballast and a 4-pin chrome box, using the same Petronix coil the FBO kit comes with.
Based on info above and a few wiring diagrams I've reviewed, I believe it's safe for 4-pin ECU to bypass the ballast as long as the coil is up to it.
Happy to be the crash test dummy here... if my ECU burns up I'll be sure to report back.
Thanks for the replies and info guys!
:twothumbsup:
Constant 12V is hard on coils . Issues tied to Long term reliability ....
I learned this in auto-tech class , circa 1980. Not sure if this still applies. Jut throwing it out.
Quick follow up on this... looking for a more permanent ballast bypass than my jumper setup.
Think this diagram is accurate:
(https://www.thelightninground.com/filedata/fetch?id=1907&d=1600021469)
At startup do both the start and run circuits get 12v?
Thinking of making a permanent connection from the blue "run" circuit to the coil, but need to verify it gets power at startup as well.
The brown wire gets power from the ignition switch in "start". The blue wire does NOT. Once you let off the key, power drops off the brown wire and goes to the blue.
:that diagram is not accurate IMO..
Confusing at best
The ballast resistor also compensates for temperature and rpms. This link gives a good explanation for the original use of a ballast. http://blog.simonbbc.com/ballast-resistors-resistance-and-coils/
Quote from: Burdar on September 14, 2020, 05:49:59 AM
The brown wire gets power from the ignition switch in "start". The blue wire does NOT. Once you let off the key, power drops off the brown wire and goes to the blue.
So the 2 wires from the ignition switch are brown and blue. Guess I need to locate a better diagram.
If that's accurate it sounds like simply tying the brown and blue together prior to the coil and bypassing the ballast would do the trick yes?
My experience with running a full 12 volts+ all the time to the coil will result in coil failure. I had many people try to tell but I kept reading this article here and there how it would work just fine. I was bullheaded and couldn't see any reason why it shouldn't. After breaking down a half dozen times do to coil failure I went back to running a ballast resistor. I probably tried 4 different brand coils and it didn't matter. Haven't had one issue since going with the ballast for the last 2 years. :alan2cents:
QuoteMy experience with running a full 12 volts+ all the time to the coil will result in coil failure. I had many people try to tell but I kept reading this article here and there how it would work just fine. I was bullheaded and couldn't see any reason why it shouldn't. After breaking down a half dozen times do to coil failure I went back to running a ballast resistor. I probably tried 4 different brand coils and it didn't matter. Haven't had one issue since going with the ballast for the last 2 years.
The coil has to be designed to run without a ballast. Most coils are not. Pertronix sells two coils. One is oil filled and the other is epoxy filled. Both are designed to run on 12v.
That's what I was thinking as well. I actually tried their oil filled one. It died as well after about a month. :notsure:
Quote from: Scooter on September 14, 2020, 01:09:20 PM
Quote from: Burdar on September 14, 2020, 05:49:59 AM
The brown wire gets power from the ignition switch in "start". The blue wire does NOT. Once you let off the key, power drops off the brown wire and goes to the blue.
So the 2 wires from the ignition switch are brown and blue. Guess I need to locate a better diagram.
If that's accurate it sounds like simply tying the brown and blue together prior to the coil and bypassing the ballast would do the trick yes?
That is what is normally done when changing to an MSD Ignition that was designed with no ballast
Quote from: dodj on September 15, 2020, 07:53:45 AM
Quote from: Scooter on September 14, 2020, 01:09:20 PM
Quote from: Burdar on September 14, 2020, 05:49:59 AM
The brown wire gets power from the ignition switch in "start". The blue wire does NOT. Once you let off the key, power drops off the brown wire and goes to the blue.
So the 2 wires from the ignition switch are brown and blue. Guess I need to locate a better diagram.
If that's accurate it sounds like simply tying the brown and blue together prior to the coil and bypassing the ballast would do the trick yes?
That is what is normally done when changing to an MSD Ignition that was designed with no ballast
Had to do the same bypass on my Ford when I installed the MSD dizzy and 6AL box. Except Ford uses a "pink" resistance wire instead of a ballast resistor.
Found another diagram for the earlier 5 pin ECU unit that states the run position has power at all times:
(https://www.thelightninground.com/filedata/fetch?id=1915&d=1600122782)
Cant imagine the ignition changed for the "73-74" 4 pin ECU with single ballast.
This would make life a bit easier as I could just terminate the start leg and wire the run leg right to the coil.
Would it make any sense to not have the run leg have power at startup and for the ignition circuit to actually have to transition from start to run with a complete dropout of volts between the two ignition positions?
On the coil issue, Petronix says full 12v for this application:
(https://www.thelightninground.com/filedata/fetch?id=1917&d=1600189433)
Gotta hope they know their own coils... lol.
QuoteFound another diagram for the earlier 5 pin ECU unit that states both the run and start positions have power at all times:
Test it and report back. Disconnect the ignition switch connector at the base of the steering column and test both the blue and brown wires. With the connector disconnected, you won't be getting any feedback from the brown wire since it's spliced to the blue at the ballast. You'll be testing just the ignition switch to see how it distributes power.
Quote from: Burdar on September 15, 2020, 10:27:39 AM
QuoteFound another diagram for the earlier 5 pin ECU unit that states both the run and start positions have power at all times:
Test it and report back. Disconnect the ignition switch connector at the base of the steering column and test both the blue and brown wires. With the connector disconnected, you won't be getting any feedback from the brown wire since it's spliced to the blue at the ballast. You'll be testing just the ignition switch to see how it distributes power.
Looks like I'm going to have to crawl up under there.
Modified the above post to reflect actual thought...lol
"Found another diagram for the earlier 5 pin ECU unit that states
the run position has power at all times"
need more coffee.
I knew what you meant. Would be interested to see if the blue wire still has power during "start" though.