distributor and ballast

RJRENTON · Feb 2, 2022

Nacho-RT74 said:
I meant, being somehow arrogant, offensive or disrespectful on my replies "buddy", I never did, do or will.

But.....sometimes up is down, except when down is left or right, but when it's down, it can be up but then it MAYBE right but never left except when its opposite up or down, then for sure its left or right, depending on one's viewpoint, which may be left or right or up and maybe down....neglecting the possibilities of the inverse ir possibly the square root factors influence ....if you understand the theory of a logistical silogism then you will no difficulty determining the answer.....except if you do not....then the answer will be perfectly clear....sometimes....except if/when its not.....think about it.....if you can.....
BOB RENTON

Bee1971 · Feb 2, 2022

Jesus Christ

1965ply · Feb 3, 2022

RJRENTON said:
THANK YOU.....I APPRECIATE THE HELP.....I've disassembled both the origional and present day ECU's...there is a significant difference in both components used and the circuit design. One of the most important revisions was the switching transistor on the outside of the case; it was changed to a power Darlington transistor, similar to an IGBT (Insulated Gate Bi-polar Transistor) device, with internal transient supression and an accelerator diode built in.
BOB RENTON

Bob My question from the begin was can i run it on a dyno with out ballast resistor, there's no alternator on motor just distributor possible run time of 1/2 hr and not at same time
thanks
Charlie

RJRENTON · Feb 3, 2022

1965ply said:
Bob My question from the begin was can i run it on a dyno with out ballast resistor, there's no alternator on motor just distributor possible run time of 1/2 hr and not at same time
thanks
Charlie

IMO....in real,life, in a vehicle on the road, the ballast resistor is in the circuit 99.95% of the time, with the remaining 0.05% of the time, it is bypassed during starting. To perform dyno runs with a short run or on time with the ECU AND COIL receiving full 12 volts 100% of the time, for a maximum of 30 minutes total, would PROBABLY be ok, but there is ALWAYS the possibility of ECU AND COIL failure, due to the high voltage applied all the time. Do you feel lucky?? You can always change you mind.....or say "WTF" and proceed.....just my opinion of course.
BOB RENTON

Bee1971 · Feb 3, 2022

Another Words

In Simple Terms

What I said in POST #8

Without All The Bullshit Afterwards

Thanx Scott

RJRENTON · Feb 3, 2022

Bee1971 said:
Another Words

In Simple Terms

What I said in POST #8

Without All The Bullshit Afterwards

Thanx Scott

Not necessarily......I was trying to make the OP AWARE of the potential risks and consequences of his decision and to allow the OP to decide but I guess it depends one's frame of mind....sort of a "conservative" or "liberal" mind set approach....
BOB RENTON

BeepBeepRR · Feb 3, 2022

Are you trying to break the engine in? Cam break in is around 20 25 minutes. Or just running it on the dyno for some HP pulls?

1965ply · Feb 3, 2022

BeepBeepRR said:
Are you trying to break the engine in? Cam break in is around 20 25 minutes. Or just running it on the dyno for some HP pulls?

already broke cam in, just want to do some pulls, we suspected something wrong with dist in motor and the only spare i have is electronic igntion so i know i have to hook box up

BeepBeepRR · Feb 3, 2022

1965ply said:
already broke cam in, just want to do some pulls, we suspected something wrong with dist in motor and the only spare i have is electronic igntion so i know i have to hook box up

You can run it with putting a jumper across the ballast resistor terminals. I had to do this to get home one day. So to answer your question Yes it can be done. But I would re-install a good ballast resistor when done.

Sixpactogo · Feb 3, 2022

BeepBeepRR said:
After installing an aftermarket Summit branded electronic ignition orange box on my friends Roadrunner. Took it for a drive and went about 20 miles it started to break up and run like crap. I pulled into a gas station and the coil was super hot to the touch. The car would not fire back up. I let the coil cool off for about 30 minutes. Tried to start the car again and no go. The coil was a yellow accel super stock coil or something like that.

Anyhow even after letting the car sit for that 30 minutes still no fire. I had to end up doing a jumper on the ballast resistor which was a single resistor to get the car to run. I never fully understood why it malfunctioned I assume it smoked the resistor. But bypassing it fixed the issue and was able to make it home without further issue. It was wired properly as per the schematics that came with the Summit branded ECU and Distributor kit. Maybe someone knows why it died.. I assume the ballast resistor failed causing full 12volts to the coil which overheated it. Correct me if I am wrong.

Beekeeper, I believe the failure on your friends Road Runner occurred because of a poor ground or lack of one on the ECU as shown in your second diagram in your post #2.
Without a good case ground on that module, about 15-20 minutes is all you will get before it gets hot and opens the circuit internally and will not close again until it cools down. That missing case ground will also overheat the coil too and possibly the ballast resistor but it is the ECU circuit that opens up. A half hour cool down sounds about right as I have been through that scenario myself a couple times before learning what the problem was. A lot of guys want to blame the orange box as being the culprit when it was their own fault for not verifying that ground. Now I always make sure I have less than .3 ohms between the ECU case and the Neg post on the battery. Fresh paint makes for bad grounds and bad grounds cause most of our electrical issues. Have never had one fail since.

BeepBeepRR · Feb 3, 2022

Sixpactogo said:
Beekeeper, I believe the failure on your friends Road Runner occurred because of a poor ground or lack of one on the ECU as shown in your second diagram in your post #2.
Without a good case ground on that module, about 15-20 minutes is all you will get before it gets hot and opens the circuit internally and will not close again until it cools down. That missing case ground will also overheat the coil too and possibly the ballast resistor but it is the ECU circuit that opens up. A half hour cool down sounds about right as I have been through that scenario myself a couple times before learning what the problem was. A lot of guys want to blame the orange box as being the culprit when it was their own fault for not verifying that ground. Now I always make sure I have less than .3 ohms between the ECU case and the Neg post on the battery. Fresh paint makes for bad grounds and bad grounds cause most of our electrical issues. Have never had one fail since.

I do believe that the grounding could have been the issue. And you may just well be correct. I have thought about that after I posted that. I still have the ECU and the distributor I will be checking them out to verify. To be totally honest it never dawned on my when we were broke down that it was not getting a good ground.

70bigblockdodge · Feb 3, 2022

Stockish Chrysler ECU is only reliable to 6k. They have trouble keeping up at high RPM. I do not know why. Taxing the transistor with more volts and current seems to be asking for trouble. Will bypassing the ballast resistor get you home, sure. I'm assuming your running on Dyno to tune for max HP, if it were me I would not use the wrong parts to tune because it will all be for not when running parts are reinstalled.
For a check against other dist. sure no problem.

RJRENTON · Feb 4, 2022

IMO....
" ChrysleStockishr ECU is only reliable to 6k. They have trouble keeping up at high RPM. I do not know why."
The issue is due to the charge/discharge time constant of the coil (inductive reactance) and the ability of the ECU'S internal dwell time network to allow for the coil to charge (external transistor is on or conducting), until the next distributor's reluctor pulse turns OFF the external transistor, causing the spark to occur. Long term bypassing the ballast resistor allows too much current to flow through the switching transistor (and coil's primary winding) promoting premature failure. The fix? Use components suitable for the intended use
BOB RENTON

70bigblockdodge · Feb 4, 2022

RJRENTON said:
IMO....
" ChrysleStockishr ECU is only reliable to 6k. They have trouble keeping up at high RPM. I do not know why."
The issue is due to the charge/discharge time constant of the coil (inductive reactance) and the ability of the ECU'S internal dwell time network to allow for the coil to charge (external transistor is on or conducting), until the next distributor's reluctor pulse turns OFF the external transistor, causing the spark to occur. Long term bypassing the ballast resistor allows too much current to flow through the switching transistor (and coil's primary winding) promoting premature failure. The fix? Use components suitable for the intended use
BOB RENTON

I agree, they did have a chrome, or gold box for over 6k and up to 10k or something like that. I just thought if the OP is paying for Dyno time using a dist that may not keep up with the combo is not pennywise. I'm on a dual point fwiw.

Old Sparky · Feb 9, 2022

1965ply said:
Hi have a 440 its on the Dyno, and we think we have a issue with the distributor and its a plug and play unit, i want to change to see if it makes any difference but the only spare i have is a Chrysler electronic one so i have to use the box with it as well, but do i have to use the ballast resistor to, motor is still on dyno so we want to make other run on it and compare
thanks
thanksView attachment 1233228

Needing a ballast resistor totally depends on the coil.
Most stock coils need them but many aftermarket coils do not. It will depend on where the coil came from. If it came from a vehicle that had one the you will have to use it.

RJRENTON · Feb 9, 2022

Old Sparky said:
Needing a ballast resistor totally depends on the coil.
Most stock coils need them but many aftermarket coils do not. It will depend on where the coil came from. If it came from a vehicle that had one the you will have to use it.

Can you provide a comprehensive list of the aftermarket rcoil's that require a ballast resistor vs those aftermarket coil's that do not require a ballast resistor. Perhaps you could, in the same comparison, add a column for those ECU's that are compatible with the respective coil. Just a thought.....
BOB RENTON

70bigblockdodge · Feb 9, 2022

Old Sparky said:
Needing a ballast resistor totally depends on the coil.
Most stock coils need them but many aftermarket coils do not. It will depend on where the coil came from. If it came from a vehicle that had one the you will have to use it.

My car is on a single point distributor. If I buy a coil for a 1998 Dodge 1500 (no ballast resistor) I will no longer need a ballast resistor on my '68 Charger?

Old Sparky · Feb 9, 2022

70bigblockdodge said:
My car is on a single point distributor. If I buy a coil for a 1998 Dodge 1500 (no ballast resistor) I will no longer need a ballast resistor on my '68 Charger?

Yes if the coil does not have one originally then it is not required....but beware of using parts from computer controlled engines on older engines.

70bigblockdodge · Feb 9, 2022

Old Sparky said:
Yes if the coil does not have one originally then it is not required....but beware of using parts from computer controlled engines on older engines.

My points are going to love that.

Old Sparky · Feb 9, 2022

RJRENTON said:
Can you provide a comprehensive list of the aftermarket rcoil's that require a ballast resistor vs those aftermarket coil's that do not require a ballast resistor. Perhaps you could, in the same comparison, add a column for those ECU's that are compatible with the respective coil. Just a thought.....
BOB RENTON

No I can't ...I have no list. I would not use any coil that has a resistor without one as the points will not last much more than a 100 miles, tried that one back in the 60's ....coils from computerized engines don't enter into this discussion....you have to know the specs of the coil to know if it will work without a resistor... I do not remember the coil resistances that denote the difference......Just had an extra thought here seems like the mention of ECU's came to mind as why anybody brought them into this thread.....perhaps you might mean EIM's (electronic ignition modules)????....Have just done some digging and ECU could be correct in some areas I suppose...my apologies ...have never heard of them being called that. As far as I new they were always called electronic ign mods,,,,sorry....to me an ECU is an engine control unit not just ignition control unit.

distributor and ballast

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