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-   -   Ballast resistor (https://www.fordbarn.com/forum/showthread.php?t=345972)

oldredford 01-28-2025 06:27 PM

Ballast resistor
 

Both my 1940 Fords with stock ignition, they work better without the ballast resistor. What are your thoughts on running the resistor?

Kube 01-28-2025 07:29 PM

Re: Ballast resistor
 

Quote:

Originally Posted by oldredford (Post 2365636)
Both my 1940 Fords with stock ignition, they work better without the ballast resistor. What are your thoughts on running the resistor?

They will seem to run better as the coil is getting the full 6v. Run it like this for a while and you'll find it'll run worse than ever; a LOT worse. You will burn up the coil and / or points. No way around it.

deuce_roadster 01-28-2025 11:14 PM

Re: Ballast resistor
 

What Kube said x2.

aussie merc 01-28-2025 11:22 PM

Re: Ballast resistor
 

works great till you let the smoke out dammed if you can buy a refill

tubman 01-28-2025 11:31 PM

Re: Ballast resistor
 

1 Attachment(s)
Quote:

Originally Posted by aussie merc (Post 2365697)
works great till you let the smoke out dammed if you can buy a refill

Really? I would think that you folks "down under" could get a deal on this :

aussie merc 01-28-2025 11:33 PM

Re: Ballast resistor
 

will have to keep looking

Kube 01-29-2025 09:12 AM

Re: Ballast resistor
 

Quote:

Originally Posted by tubman (Post 2365699)
Really? I would think that you folks "down under" could get a deal on this :

You beat me to it! I'd seen these and think they are hilarious. Still, probably quite necessary for some of the Lucas systems.

tubman 01-29-2025 10:40 AM

Re: Ballast resistor
 

And, since it is "positive earth", it will probably work in old Fords!:D

It doesn't say if it's for 6 or 12 volts, though.:confused:

marko39 01-29-2025 01:47 PM

Re: Ballast resistor
 

Quote:

Originally Posted by oldredford (Post 2365636)
Both my 1940 Fords with stock ignition, they work better without the ballast resistor. What are your thoughts on running the resistor?

I cooked a “new” coil in 15 minutes when I first got my engine running bypassing the resistor. ( to be honest the thing was made offshore)

ScubaChief60 01-31-2025 06:10 AM

Re: Ballast resistor
 

Well... when I was first investigating this same topic a few years back, I think I got some great advice... and several years out... my 1935's original inside firewall mounted ballast resistor and rebuilt coil are all running great... so proof is in the pudding as they say here in the Southeast US.

In that thread there is the advice from two old timers (like me) that weighed in and advised to absolutely use the ballast resistor. They also mentioned that the ballast resistor gets very hot while in use and from time to time may not work as intended as I recall when restarting an engine after a short stop.

It was recommended to me to set the ignition up on a 6 pole toggle switch (which I placed under the dash) so that one middle switch position completely disables the ignition which is a good anti theft option... and the second toggle position (which is where I have it 100% of the time now when I am driving my 1935) runs the ignition thru the ballast resistor as originally engineered... and the third toggle switch position runs the ignition directly to the coil bypassing the ballast resistor in the case that the ballast resistor should ever overheat and fail... which has never happened on my vehicle.

This setup has been great for me. Hope you find it helpful.

ford38v8 01-31-2025 07:09 AM

Re: Ballast resistor
 

Quote:

Originally Posted by ScubaChief60 (Post 2366152)
Well... when I was first investigating this same topic a few years back, I think I got some great advice... and several years out... my 1935's original inside firewall mounted ballast resistor and rebuilt coil are all running great... so proof is in the pudding as they say here in the Southeast US.

In that thread there is the advice from two old timers (like me) that weighed in and advised to absolutely use the ballast resistor. They also mentioned that the ballast resistor gets very hot while in use and from time to time may not work as intended as I recall when restarting an engine after a short stop.

It was recommended to me to set the ignition up on a 6 pole toggle switch (which I placed under the dash) so that one middle switch position completely disables the ignition which is a good anti theft option... and the second toggle position (which is where I have it 100% of the time now when I am driving my 1935) runs the ignition thru the ballast resistor as originally engineered... and the third toggle switch position runs the ignition directly to the coil bypassing the ballast resistor in the case that the ballast resistor should ever overheat and fail... which has never happened on my vehicle.

This setup has been great for me. Hope you find it helpful.

Cheif, That is great advice, but with one caveat: The resistor bypass is to be used only while starting the engine. Never continue to run an engine without the resistor's lowered voltage protection for the coil and points. The reason to bypass it initially is due to excessive voltage draw from the starter motor for whatever reason, not leaving enough to allow the coil to produce sufficient spark to fire the ignition. This is not theory, it is fact, and provable right now as you read the following scenario: You crank and crank and crank, but the engine does not fire... until the moment you release the starter and the engine starts at once. Does that sound familiar to you?

slowforty 01-31-2025 08:19 AM

Re: Ballast resistor
 

I had the resistor fail on my 40. But it would not fail completely. It would start and run well but when it failed, it would not run over 60 mph. Try to fix somrthing that wont break completely. Also try to work under the dash at 77.

glennpm 01-31-2025 09:56 AM

Re: Ballast resistor
 

Quote:

Originally Posted by ford38v8 (Post 2366155)
Cheif, That is great advice, but with one caveat: The resistor bypass is to be used only while starting the engine. Never continue to run an engine without the resistor's lowered voltage protection for the coil and points. The reason to bypass it initially is due to excessive voltage draw from the starter motor for whatever reason, not leaving enough to allow the coil to produce sufficient spark to fire the ignition. This is not theory, it is fact, and provable right now as you read the following scenario: You crank and crank and crank, but the engine does not fire... until the moment you release the starter and the engine starts at once. Does that sound familiar to you?

Totally agree with this. I have a push button intermittent switch that bypasses my resistor for starting as needed.

Glenn

aussie merc 01-31-2025 04:00 PM

Re: Ballast resistor
 

search the threads here the starter bypass has been discussed many times as for crank and only fire on release is a sign that you have an electrical problems

Low battery reserve [on its way out] or poor or failing connections/ components causing voltage drop

petehoovie 01-31-2025 04:25 PM

Re: Ballast resistor
 

There is this circuit from past posts here...


https://www.earlyfordv8.org/forum/fi...k%20Start1.jpg

ScubaChief60 02-01-2025 06:22 AM

Re: Ballast resistor
 

You all are the best.

This is a forum where knowledge and experience meet the road! :)

ScubaChief60 02-01-2025 06:28 AM

Re: Ballast resistor
 

I really like this diode method! I have used diodes over the years and they just work when properly configured into the design layout.

This would solve another worry that I have in the back of my mind with my current setup... and that is that when I am gone from this world... then I would have made my old Ford 'Idiot Proof' for the next owner. :)

ScubaChief60 02-22-2025 07:18 AM

Re: Ballast resistor
 

Just a clarification question here regarding starter bypass of the ballast resistor.

My '35 (6 Volt Pos Ground) has no solenoid as in the diagram Pete posted. So, is it OK for me to feed from the pole that feeds to the starter when the floor mounted starter switch is depressed?

I plan to install this setup along with the 'Top Hat diode' so that full power feeds the coil at startup and when switch is released then the voltage reverts to feeding thru the ballast resistor at a reduced level to save points and coil from the over voltage.

This will make it perfect for my son one day when he grabs the reigns.

Is my thinking right?

Thanks all!

ScubaChief60 02-22-2025 07:19 AM

Re: Ballast resistor
 

I will also install an in-line fuse on the feed from the starter to the 'Top Hat Diode'.

ScubaChief60 02-22-2025 08:04 AM

Re: Ballast resistor
 

Should I be concerned about any back feed of voltage towards the ballast resistor during the brief period when the starter switch is depressed? Would a second diode here be a good idea to prevent 6 volt back-feed or does it not matter?


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