I have changed my 51 over to 12 volt neg. ground. I just got my generator changed to and got it back on the road. Everything is great as far a starting the truck through the day. The problem I'm having now is when I drive it at night for a few nights in a row the lights will start to get dimmer and then the truck won't start b/c the battery is dead. First I thought I had a weak battery b/c I'v had it a while, so I switched it out with a new one my dad had. It also ran it down to lastnight b/c I drove it alot yesterday. It's like my gen. isn't keeping my battery up at night. I'm going to check some wires out tomorrow and see if I can find something. I've looked at a couple of pics and I see that most of the flatheads have a ground cable run from the motor to the fire wall. My neg. cable is grounded to my motor but do I need to put a second ground cable on the motor and run it to the fire wall on my truck. Will this help out on my charging problem. Or is there a easy way to tell if my gen. is charging right. The guy said he put it under a load and it done great. I have used this guy before and he is good but I know people can make mistakes or things go bad again. At night my charging needle is in the middle and when I turn my lights on it drops down a line to the decharging side. So I know it is sucking my battery dry. Any idea's and help would be great.

Scott B.
1951 F1
239 Flathead V8 3 on the tree

 

I would ground the engine to the frame.

 

You can't have too many grounds. I connect my neg. terminal (ground) to the engine and run heavy (8 ga.) grounds from there to the cab, frame, and alternator body. If I were running a gennie, I'd run one to the screw that holds the regulator to the firewall. All these connections need to be paint-free and cleaned.

When you convert a 6v generator to 12v, they don't put out as much current, so it is possible it just can't keep up at night, but most people don't have that problem unless they have a bunch of lights or electric fans. When you first start it with a near-dead battery (lights off), how much charging does the ammeter show it's putting out?

What did you use for a 12v regulator?

 

I have almost the same problem. I'm going to check my ground, I only have a ground to the block right now. I'll run a heavy wire to the cab.

 

The regulator I used I bought a couple at the Louisville swap meet. They was fairly cheap b/c I bought 3 of everything I needed to do the 12 volt conversion. We was planning on doing my dad's 46 so that's why we bought that much. I have one ground running to ir but it is the ground that runs through the main wiring harness. I'm going to put somemore grounds on it tomorrow. I'll run another from the reg. to the firewall. One from the motor to the frame, and one to the cab. When my truck is running the amp meter stays in the middle at all times. Never shows charge, only show it decharging when I turn my lights on. The parts I bought at the swap meet might be my problem to b/c he had a good price on everything so it might pay me to invest in some more quality parts. It just puzzled me b/c all my problems since I done the conversion seem to happen to me at night b/c of the extra load on everything. Hopfully these extra grounds will solve my problem. Thanks for all the help.

Scott B.
1951 F1
239 Flathead V8 3 on the tree

 

If all parts and systems are operating correctly and your gen charging circuit can't provide 12 plus volts under any or all loads, I would go to an alternator. They come in many different load amounts and you can delete the regulator. They are easy to find and the cost is reasonable. Have a great day,chuck

 

Scott, this may be a dumb question but I'm going to ask it anyway. If I understand you correctly, you are using a 12V generator. Did you remember to "flash" the fields when you installed it and the new regulator? I ruined a couple of generators when I was a kid by not doing that.

 

I did the regulator but I didn't the Gen. Do you have to do the Gen. the same way, and If so can I still do it or is it to late. God I hope I haven't ruined that Gen. I have had it on there about 2 weeks and I have noticed when I take the positive cable side of the battery off at night when I do have trouble with it, it is alittle warm. Man I hope I haven't ruined this Gen. I didn't know you had to flash it like a new Regulator.

Scott B.
1951 F1
239 Flathead V8 3 on the tree

 

You may not have the right kind of regulator, or there may be a reason they were cheap at the swap meet! Are they from late-50's Fords? Something isn't working and it doesn't sound like it's the generator. If you really want to run a gen, I'd get well acquainted with the section in the shop manual on testing and setting the regulator. Once you understand them, they aren't that hard to troubleshoot.

 

Scott, you do the regulator and generator at the same time. As I remember it, after installing the gen. & regulator, hook up the battery. Place a jumper wire between the battery & field terminals on the voltage regulator, count to "5" and remove it. I haven't done this in years, so maybe someone will chime in with more info. Verify this procedure before you try it, I would hate to give you the wrong info and cause you to damage your system. Hope this helps. Good luck.

Gil

 

No, don't use a jumper wire. That was procedure with the early cars/trucks with a 3 brush generator.

With the late series the shop manual is clear:

With all parts connected correctly, before starting the engine and with the key off, remove the field wire from the regulator and briefly (1 or 2 seconds) touch it to the batt connection of the regulator. You should see a small blue spark. Reconnect the field wire.

Since you've gone to 12V, just get a regulator at NAPA for a 57 Ford truck.

 

Great advise Chuck! Generators are dinosaurs. They hardly kept up a charge with lights on when they were brand new. You have already changed it over to 12V negative ground so obviously you're not a purist. Get an alternator and be done with it. There must be a reason cars don't come with generators anymore.....

 

All you guys thank very much for the help. I'm going to try some of the things you all mentioned. I talked to a friend of my dad's today and he still has the car he drove to high school just got it done a couple of months ago. It's a 40 model mercury conv. He had it since he was 16 and he is about 55 to 60 yrs of age know. It's all original with the exception of he has a 2 carb set up and headers on his flathead. He is running a Alternator on his flathead to. He said it's just easier and better. One wire set up I believe what he has. He told me what I would need to buy to put the Alt. on as far as the kit to make it work. I'm still going to try your all's advice for know b/c the car shows are all most over for this year. ( I hate that to) I would say I'll be looking into a Atternator for my truck before long. I lovr driving it every chance I get so I want it to be right so I don't have to get out a push it and hurry and jump back it and clucth it in second to get it running again. It wasn't funny then but I laugh at myself know, b/c you know people was wondering what the heck is that boy doing.LOL!!! Thanks Guys Again.

Scott B.
1951 F1
239 Flathead V8 3 on the tree

 

That's why I usually try to carry a teenage son or two when I go someplace

 

I had my son with me to but he is only 2 1/2 yrs old and I don't think he could push hard enough to help me out. LOL!! All though he was YELLING Go Daddy Go!!!!! Couldn't hardly push the truck from laughing at him. We still had a great cruise that day anyway.

Bobj49f2,
BTW did you ever get the 16" wheels on your panel truck?

Scott B.
1951 F1
239 Flathead V8 3 0n the tree