Shorted out alternator!

joltesvig

joltesvig

Senior Member
Thank you Ford Barn experts for helping me find out why my 31 Coupe would not start!
Turns out that the fuse, mounted on top of the left front frame rail, was blown! Wow, what caused that? I disconnected the alternator wire and put a new fuse in and she started and ran fine. Of course the battery will gradually run down since the alternator is disconnected.
I guess I'll take the shorted out alternator to my Advanced Auto Parts store where they can get me a replacement and I can get credit for the core. UNLESS someone has a better idea. Keep in mind that I am a Model A rookie and I don't know what I'm doing.
Cheers
 
Are you still running 6 volt pos ground (original set up) advance auto may not have the correct alternator
 
You don't say why you think the alternator is shorted out. Fuses blow for a variety of reasons. The fuse being blown doesn't indicate a shorted alternator.
 
Oak & Larry,
Yes 6v pos ground...maybeAdvance won't have a replacement! If not, where can I get a replacement?
The reason I think it is a shorted alternator is that With it still connected, I noticed that when I started putting a new fuse in the holder, the fuse started to heat up real fast. That's when I decided to takethewire off the alternator and, I guess I got lucky, the fuse did not fail then and she started up and ran just fine.
With battery charged up, how long can I drive before the battery will run down and I won't be able to strt her...the ammeter does not show much discharge?
I guess I should put an ohmmeter across the alternator just to verify that it is a direct short?
Thanks for your feedback because sometimes I can't find my but with both handson this electrical stuff!
Cheers
 
With a fully charged good battery you should have no problem driving 8 hours, unless you do a lot of stops and starts. The coil only draws 1 to 2 amps while the engine is running. If you use the lights, they will take about 10 amps or more, so you'll want a generator to keep up with the demand.
 
Maybe I missed something. If you are using a typical 10si that is negative ground, on a positive ground car it will be shorted. They take special rectifiers and the VR is wired differently. If it is a negative ground alt you may not have hurt it.
Gonna be tough to find the right one at an auto store.
 
If still running 6V pos grd,why not put a rebuit original generator on?A properly rebuilt gen is good for 100,000 miles and will be original.Besides,an alt looks ugly on an A.JMHO.
 
Ken Davis is a good source for
6v pos ground alternators
if this is truly the problem, but I'd ohm it out first
Modern auto supply places will NOT have this alternator, and they will have a seizure if you ask them
 
joltesvig said:
Oak & Larry,
Yes 6v pos ground...maybeAdvance won't have a replacement! If not, where can I get a replacement?
The reason I think it is a shorted alternator is that With it still connected, I noticed that when I started putting a new fuse in the holder, the fuse started to heat up real fast. That's when I decided to takethewire off the alternator and, I guess I got lucky, the fuse did not fail then and she started up and ran just fine.
With battery charged up, how long can I drive before the battery will run down and I won't be able to strt her...the ammeter does not show much discharge?
I guess I should put an ohmmeter across the alternator just to verify that it is a direct short?
Thanks for your feedback because sometimes I can't find my but with both handson this electrical stuff!
Cheers
Click to expand...
Kendavismodela.com sells the brand new 1 wire alternators. 6v or 12v. Had one on both of our cars for 20 years with no problems. They were on the cars when they were 6v then when we switched to 12 volt we kept the same alternator and ken just switched them to 12 volts when we switched over
 
Just change over to a neg ground Alt. It will give you a greater variety of vendors. All you need to do is swap the wires on the alt and on the coil.(I think Willie has the right idea and your alt is already neg ground)
 
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Thanks for all the good advice!
I disconnected the alternator and I am currently driving off the battery which Mike suggests should be ok for several hours of driving.
It is good to be back on the road again.
The guy in Norwalk, Ohio will repair my alternator ... Hopefully he will return my phone call soon so I can get the ball rolling on the fix.
In the meantime I'll just use the old battery charger to keep the battery up.
Question about battery chargers with my 6volt battery... Can I overcharge the battery? If I charge it with the 6 volt setting or 12 volts low amperage setting, will it make any difference?
 
Oops...Tom's advice on the several hours of driving with no charging. I hope she starts with little cranking when I'm away from home!
Another question: would getting a jump start from a 12 volt vehicle hurt my 6 volt positive ground system as long as we get the polarity right?
 
Oops...Tom's advice on the several hours of driving with no charging. I hope she starts with little cranking when I'm away from home!
Another question: would getting a jump start from a 12 volt vehicle hurt my 6 volt positive ground system as long as we get the polarity right?
 
Jumping a 6 volt battery with a 12 volt battery is hard on both batteries, but it can be done if you connect - to -, then connect one cable to the 12 volt+ and don't touch the other end to the chassis of the dead car until someone is actually trying to start it with the starter engaged. It should fire right off, then disconnect the jumper right away. Using a cheap set of jumpers with thin cables will be better for the batteries, as some of the current will be lost through the cables.

Remember, you don't make the last connection at the battery. You don't want sparks around the battery, especially when jumping 6 volts with a 12 volt battery.
 
Tom Wesenberg said:
Jumping a 6 volt battery with a 12 volt battery is hard on both batteries, but it can be done if you connect - to -, then connect one cable to the 12 volt+ and don't touch the other end to the chassis of the dead car until someone is actually trying to start it with the starter engaged. It should fire right off, then disconnect the jumper right away. Using a cheap set of jumpers with thin cables will be better for the batteries, as some of the current will be lost through the cables.

Remember, you don't make the last connection at the battery. You don't want sparks around the battery, especially when jumping 6 volts with a 12 volt battery.
Click to expand...

Would it be best to ground out on the head stud, and then just lightly tap the other cable on the bolt of the starter switch (not clamp it down). that way you're only getting momentary current flow? so not to damage anything.

PS- set the parking brake. If you have your foot on the brake pedal while trying to jump it, it'll blow the bulbs.
 
I jumped started my 6V chev with a 12V battery ONCE. Cold winter day with long cables.

With the Model A, I would use the hand crank if at all possible BEFORE the 12V jump.

Marc
 
Jordan said:
Would it be best to ground out on the head stud, and then just lightly tap the other cable on the bolt of the starter switch (not clamp it down). that way you're only getting momentary current flow? so not to damage anything.

PS- set the parking brake. If you have your foot on the brake pedal while trying to jump it, it'll blow the bulbs.
Click to expand...

Yes, that's how I would do it and have done it in the past.

As Marc said, if at all possible, I would use the hand crank.:)
 
When I jump start a 6 volt something from a 12 volt something, I use cheap Wallyworld cables. I connect the 12 volt somthing to the jumpers first, then the proper cable directly to the stud on the starter. If possible I have someone engage the starter switch, then I make the last cable conection to a bolt or a bracket and hold it there until the 6 volt something starts.
 
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