Topic: Failing 12 v. alternator system in 37 Ford V8


macodell    -- 06-20-2017 @ 1:39 PM
  My 1937 Ford V8 4-dr. convertible has been totally rebuilt A-Z and equipped with modern 12 v. electrical system which fails repeatedly; replaced fan mount and alternator only to have system quit again, and again; now on 4th alternator which failed again. Car runs great for 100-200 miles or more then battery and lights go completely dead and car can't even be started with a push or jump. Replacing alternator and checking voltage regulator, all circuits solves problem, but only temporarily.


MG    -- 06-20-2017 @ 2:16 PM
  See this thread for one or two wire alternator wiring diagram:

https://fordbarn.com/forum/showthread.php?t=45273&highlight=Alternator+wiring+diagram


len47merc    -- 06-20-2017 @ 2:34 PM
  macodell - you did not ask a specific question, you only stated your condition and your facts. We can assume what you are looking for, but it would be much more helpful and clear if you would clearly state what you have done so far to resolve your issue and what specifically you would like this Forum to do in support of your need.

Obviously you have a problem - likely a short somewhere but who knows - how your car was running before this issue surfaced and what you have done so far to diagnose it is very important. Thanks in advance for advising the same.

Follow MG's wiring diagram to the nth degree then come back with some specifics. Otherwise it's like hunting for the proverbial needle in the haystack.

Steve

This message was edited by len47merc on 6-20-17 @ 2:35 PM


CharlieStephens    -- 06-20-2017 @ 3:41 PM
  Since it runs good for a couple of hundred miles I would assume the wiring is OK. Is it one of those units that is stuffed into an original generator housing and is it possibly over heating? Did you send it back to the person that made the conversion originally and ask them what was wrong (maybe overheating)?

Charlie Stephens


pauls39coupe    -- 06-20-2017 @ 7:00 PM
  Do you have a separate alternator and voltage regulator? Most conversions use a GM alternator with a built in regulator or a Powermaster brand which has a built in regulator. Or are you using the old style GM alternator or earlier Ford or Mopar which required a separate regulator?


40cpe    -- 06-20-2017 @ 8:51 PM
  More questions: you mentioned a fan mount; is your fan mounted on the alternator pulley? I've read that the alternator bearings are not up to the stress put on them by a fan. Maybe an electrical shop could look at a failed alternator and diagnose what failed.


Drbrown    -- 06-20-2017 @ 9:40 PM
  In the last five or so years GM alternators are being rebuilt mostly in China, some in Mexico. I was getting many with faulty voltage regulators in them, even right of the shelf.

I would rather go to a junk yard and buy an old un-rebuilt used one, say one off a German brand, and adapt it. Some VW Alt's look like GM's regarding mounting.


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