ford flathead V8

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  #1  
Old 12-02-06, 05:13 PM
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ford flathead V8

I just replaced a 51 flathead 6Cy with a 52 Ford V8. The Amp gauge shows a discharge. How do I correct this? Thanks
 
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  #2  
Old 12-02-06, 06:33 PM
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If it has a generator(as opposed to an alternator) with the piggy back regulator I would check the power out at the regulator to make sure its charging. It could be the gauge but it's more likely the charging system or the wiring.

Hope this helps,

Bob
 
  #3  
Old 12-03-06, 06:22 AM
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I agree, you need to first verify it is charging. Is it still 6 volt postive ground?
Truck or car? - just curious - I have a 51 F-1

BTW - welcome to the forums
 
  #4  
Old 12-03-06, 10:33 AM
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Thumbs down ford flathead V8

I am trying restore a a 51 f1 truck and yes it is still 6 volt. but I am using an 8 volt battery. I feel that the generator is gharging, if I remove postitive cable from battery ( which is the ground cable ) the engine will stay running and if I check for voltage with volt meter from the negative post of the battery I get a reading of between 6 and 7 volts. Every thing worked OK with the 6Cy installed. With the V8 I get a discharge reading on the ampmeter. I tryed polarizing the the system by momentarlly by disconecting the feild wire from the regulater and momentarly touching it to the bat. terminal but nothing changed.

Thanks for any help
chilltoo
 
  #5  
Old 12-03-06, 11:13 AM
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Are you still using the same charging system with the V8 or did it come with its own system and other mounted accessories?

Try checking the polarity of the current coming off the regulator Bat terminal. It may a polarity issue with the gauge.
 
  #6  
Old 12-03-06, 12:54 PM
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The charging system I am using came with the V8. I tryed Polarizing it at the regulater but there was no change. Thanks for your input

chilltoo
 
  #7  
Old 12-03-06, 02:16 PM
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I'm not familiar with the flat head 6 but used to know the flat head V8 up and down although I've probably forgotten more than I remember

It sounds like something in the wiring is messed up. Do you know what the V8 came out of? Had it been modified any? Sometimes it is easy to forget you are dealing with positive ground so something might be wired backwards. If I remember correctly, changing the direction the amp wire runs thru the loop on the back of the volt gauge reverses the readings - I'd only do that if completely convinced it is working properly.

I ran an 8 volt battery for a while when I first got my truck [back in the mid '70's] 8 volts can be hard on the lights unless you use resistors to cut down the volts. Converting to 12 volt negative ground can be done [I did it with my tractor] and will make starting easier. My F1 is still 6 volt I like that it's unique.
 
  #8  
Old 12-03-06, 02:45 PM
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When I mentioned checking it at the regulator I meant to check if the current flow was to negative ground or positive ground. Which clip are you grounding on your meter to get the positive readings?

If the flow was to positive ground a good fix would probably be to do what Mark suggested just reverse the wires on the amp gauge.
 
  #9  
Old 12-03-06, 02:54 PM
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Originally Posted by marbobj View Post
just reverse the wires on the amp gauge
The OE gauge only has 1 wire which runs thru a loop on the back of the gauge - I don't know how/why it works - just that it does
 
  #10  
Old 12-03-06, 04:24 PM
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That's interesting. Does the wire terminate at the gauge? If it does, they must ground the case (back when there was metal in the dash). If that's the case the only way to reverse the gauge would be to isolate the gauge case from the frame grounding, run the wire coming in to the case, and ground the terminal on the back of gauge to a frame ground???? There, now I've done my thinking for the day!!

Hope that makes some sense,

Bob
 

Last edited by marbobj; 12-03-06 at 08:06 PM.
  #11  
Old 12-04-06, 06:55 AM
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Originally Posted by marbobj View Post
Does the wire terminate at the gauge?

No, it just runs thru the loop. I rewired my truck about 20 yrs ago so I don't remember exactly where the wire starts and stops. I was a little leary of replacing the old cloth [?] insulated wire thinking the new wire might not work but it did. Of course I had to do it twice because the first time I ran it thru in the wrong direction
 
  #12  
Old 12-04-06, 06:49 PM
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Thank you, that"s amazing, from the fifties too. I wonder if it's some kind of induction pickup?
 
  #13  
Old 01-02-07, 11:44 PM
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Ford flathead v-8

Hi, was wondering if you could use a manual for your old truck. I have a motors manual that covers 1935 to 1952 cars. Contact me and we will disscuss it further. Thanks, Jerbear
 
  #14  
Old 01-16-07, 06:30 PM
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charging problem

You didn't say if the ammeter showed discharge all the time or when the rpm was increased. The loop type ammeter was started in the 30s and measures the magnetic field caused by current flow thru the wire. You said you showed 6-7 volts at the batt. this is not enough to charge an 8 volt batt. The setting for a 6 volt is 6.8 to 7.2 . When you set the system up to charge the 8 volt it wont last too long. If everything is in good condition the 6 volt will do the job on this unit. One of the most often mistakes made is to put 12 volt batt cables on something like this and that won't work. Have your charging system checked out as well as the starter and put her back original.
Tom
 
  #15  
Old 01-18-07, 09:49 AM
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Tom:

This is interesting. Why would the 12 volt battery cables cause a problem? They aren't set to a resistance value are they?

Thanks,

Bob
 
  #16  
Old 01-18-07, 08:03 PM
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Batt cables

On a 6 volt system the amperage is higher requiring a heavier cable.
 
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