Hi Folks,
I've finally had a chance to tinker with the '47 one ton - can't believe it's already September! I ended up springing a 6V positive ground alternator from Quality Power in Yucaipa, because it was far and away the best price (thanks for the tip, 51504BAT!). Since the truck had sat all summer, I charged the battery up (it was still at 75% since I've got a quick disconnect for it, minimizing battery drain while it's parked). Once fully charged, I tried to start it, and found that the engine would turn only one revolution before stopping. Did this several times, but after a few times, all I'd get was the starter solenoid click. I could wait a few minutes and the whole cycle would repeat. So, I used my daily driver to give it a jump, and the engine turned nicely and started right up. While it was running, I checked the battery voltage, and the voltage coming off of the alternator. Battery was at 6.2V or so, but when I tested the post on the back of the alternator, it was a whopping 28V! With the old alternator, there was no voltage coming off the back, so this is an improvement, but not great (shouldn't it be 8V or so?).

My thinking about the sluggish starting is that it isn't battery-caused (fairly new battery) or cable caused (all new battery and starter cables and ground straps). It's also apparently not ignition caused (since it started right up with a jump), and it's not engine-related (the sluggish turning disappeared once I had an excess of juice from the 12V jump). If I'm thinking right (and here is where I'd love to hear your opinions), the most likely culprit is the starter motor, or maybe the starter solenoid. Perhaps I'm losing a bunch of voltage there, so that it takes an excess of voltage to get adequate spin on the starter motor?

The other issue (high voltage coming off of the 6V alternator) is a complete mystery to me, but is worrisome (I'm afraid that I might cook my battery pretty quickly). I wonder if it could possibly be related to the weird massive current draw that was happening every few seconds when I was having the battery charged at a service station. Has anyone else in the group experience unusually high voltage coming off of an alternator?

Thanks in advance for any and all suggestions!

 

I just read on the web that alternators can put out way more voltage than they need to, but that the vehicle's voltage regulator keeps it from doing so. Sounds like I need to look into getting a new voltage regulator. If the current one (pun intended) is bad, that might also explain the odd current draws, right?

 

Shouldn't your new alternator be internally regulated?? An alternator usually is and that eliminates the need for the regulator altogether. I have an alternator on mine and the regulator looks like it is hooked up, but I'm only using it to hide the wire connection that used to go to the regulator. The 2 wires on the left of the regulator are tied together inside the regulator housing. I removed everything else from inside.

 

It's a one-wire alternator, and I haven't been able to find anything on whether it has an internal regulator, but if alternators typically do, I don't see why this one wouldn't. That would make the 28V output all the more puzzling. I suppose it's possible that they sent me a faulty unit, but given all of the other electrical issues I've been having, I think it's more likely that something else is causing these problems.

 

28vdc out of the alternator just can't be right. In reading up on this particular alternator, the output should be somewhere around 7.5 to 8.5 vdc @60amps.
Also according to the web site, the alternator is internally regulated and they provided a wiring diagram for hooking it into the system that looks like what I did with mine. Check all your connections, etc. which I'm sure you have done and remeasure the output. Something can't be right there. Have you had the battery load tested? You mentioned something odd going on while having it charged? I will also guess you have the "correct" sized wire and connections for the amperage load, so we are probably looking at a wonky alternator or internal regulator...

 

If there is a concern about the alternator get back in touch with the guys at Quality Power. I've bought 2 alternator conversions from them and a high torque starter for my flatheads. I recently had a problem with the starter and I took it back to them and they were initially going to send it back to the manufacturer but then decided to repair it for no charge so I didn't have to wait for the new/repaired starter to be returned. Good people to deal with and they should take care of you if there is a problem with the alternator.

 

Good to see you're back from the far North and back to working on things that REALLY matter! I'll let you know next time I'm in Whatcom County. Wish I could help you with your current problem, but electrical matters aren't my strong point. Best of luck with it.

 

Following the advice of newold46, I took a closer look at the wiring. You see, when I bought the truck, it'd been completely rewired, including adding an aftermarket gauge. I had assumed at the time that the person who did the wiring knew what they were doing, but I may have been too generous. I do have all new harnesses that I plan to use to re-do the wiring with over the winter, but until then, I'm going to have to work with the existing wiring. I have no idea if the wiring that's in the truck right now is of the correct gauge.

It looks like there is no longer a voltage regulator, in that what appears to be the regulator (behind dash, on firewall - see photo), is totally disconnected. There is a fusebox, and I also include a photo of that, in part to show the ugly-looking wiring job that I'll be replacing. I've followed every wire associated with the starting system, and have done my best to produce a diagram depicting the wiring (attached). Having never seen what these looked like originally, I don't know for sure what might be amiss. However, one thing that stands out to me is that right now, the wire from the alternator is actually routed to the aftermarket dash gauge, and then to the starter solenoid. Where should that wire be attached, if not to the regulator? The other thing I see is that there is a third wire on the back of the ignition switch (key) that currently goes to nothing. What should that connect to?

Thanks folks - you're a huge help!






Fuse box and ugly wiring





Voltage regulator





Current wiring for starting system

 

GB - it'd be great to see you again. I hope summer's treated you well. From the posts, it looks like you've kept yourself plenty busy!

 

Something that may also be useful to note - the aftermarket gauge has never shown any sign of charging (the needle never budges), even with the new alternator. So maybe there's a short the gauge.

Also, is it normal to have that many things wired to the starter solenoid? Seems like a lot of action concentrated at one point...

 

The second picture is the circuit breaker that is original to the electrical system. No fuse boxes then. The left most connections are for the ignition, the others go to the ignition switch, etc. Let me see if this fancy link works for you. Hopefully it will help you to figure out what I am saying because I can't seem to word my explanation in a way where I can understand it either. If the links doesn't work, let me know and I will try something else.
Yes, there are too many things attached to the solenoid. Disconnect the aftermarket gauge from everything and then attempt to rewire accordingly. You can use the fuse box but inline after the circuit breaker. Then again we have no idea if the circuit breaker is any good, but this would be a way to find out. I found a NOS circuit breaker on ebay cheap.

 

Thanks for the insight and sharing the photos. The link didn't work (required a login/password), so if you could set it up another way, that'd be great.

 

Figured as much so I send you a PM.

 

So little things bug me and I've been contemplating your current setup. The circuit breaker has been bypassed, which isn't too terrible. So the wires that should hook up to it instead would go to the fuse box. The exception to that would be the hookups for the ballast resistor. You may or may not need those anyway, depending on where you are going from here. If you replace the points with something electronic, then you shouldn't need the resistor. Right now though, this could be part of your starting problems. Read up on it here:
Ballast resistor

 

Interesting...right now, that pink wire I've drawn from the ignition switch to the ignition coil is actually 2 wires connected in series, with nothing between them. I guess that's where I'd insert a ballast resistor.