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From: ems@amdahl.UUCP (ems)
Newsgroups: net.auto.tech
Subject: Re: conversion of 6 volt to 12 volt system
Message-ID: <2226@amdahl.UUCP>
Date: Wed, 13-Nov-85 13:37:12 EST
Article-I.D.: amdahl.2226
Posted: Wed Nov 13 13:37:12 1985
Date-Received: Fri, 15-Nov-85 08:23:08 EST
References: <362@cbuxc.UUCP>
Distribution: net
Organization: Circle C Shellfish Ranch, Shores-of-the-Pacific, Ca
Lines: 75

> I have a 63 Ford model 4000 tractor. This is a full size agricultural
> tractor. It has a standard starting system and ignition system, the
> components are:
  ( generator, starter and solinoid, regulator, coil, lights )
>
> The problem: The 6v starter system is crummy, it turns slowly and in the
> winter will sometimes not start. I have jumped it with a 12volt battery
> and found that the started (as expected) turns faster and the overall
> starting interval is shorter.

While in school, one of my friends was in the habit of buying old VW's
of the 6v kind.  We would then convert them to 12v.  What we discovered
was that 6v just didn't have enough left after line losses to turn
the starter.  12v did a dandy job (as you have discovered).  After
the line losses there was about 8-9v left at the starter, which
was fine.  We never changed the starters or solinoids.
> 
...
> Since the generator is shot and the battery is 3+ years old, I am considering
> converting to a 12 volt system. I would replace the generator and the 
> regulator with a DELCO alternator (I would use one with a built in regulator),
> the ignition coil, lights, solinoid, etc with the 12volt counterparts. However,
> there is NO 12volt starter available - I must use the 6 volt starter. So the
> questions are:
> 
> 		1) can I use a straight 12 volts on this critter without
> 		   a premature meltdown (what would the voltage drop be,
> 		   etc.)
We did with no problems, just the curing of the 6v problem.
> 
> 		2) should I try to rig a voltage eater in series with the
> 		   starter and battery:
We found no need for it.
> 			a) do they make a .048ohm/750watt resistor?
Yes, they are used in power converson equipment.  It is a spiral of
nichrome on a ceramic core.  They are BIG and get HOT.  But why bother?
Most of the extra 6v gets used up pumping the starting current through
all of the cruddy cables and connections (on older machines).
> 
> 			b) is the an electronic way to do the same thing?
> 			   (e.g. SCR etc.)
Yes, but at the current you are talking about it will be EXPENSIVE.
> 
> 		3) since the system is positive ground, can the case polarity
> 		   of the DELCO alternator be reversed or can the starter
> 		   be operated reverse polarity (since it is a D.C. motor
> 		   I would expect it to run the other way?)
The motor may, or may not, run in 'reverse'.  I don't know.  Most
DC motors, though, do have a polarity preference.  I would try to
convert the polarity of the alternator or get an alternator of the
correct polarity.  (Do British cars still use er, 'Positive Earth'?)
> 
> Any help would be appreciated and yes I KNOW this is "net.AUTO.tech" not
> "net.TRACTOR.tech", but I had hoped that someone out there might be
> willing to tackle this problem anyway.
> 
> 		j.r. miller, at&t bell labs, columbus, oh, us of a

We would also leave the original coil in, unless it died.  Often
they would continue to work.  We would change the major bulbs, that
is headlights and taillights but leave the others.  The instrument
panel lights would often work just fine and be VISIBLE to boot.
(Something they had not been before ...)
In large measure, the 12v just fixed the failings of 6v and
shortened the life of some bulbs.  Keep a fire extinguisher handy
during the 'smoke test' and don't worry about the small stuff.  We
never had to use the extinguisher, but tractors arn't VW's either ...
-- 

E. Michael Smith  ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems

'If you can dream it, you can do it'  Walt Disney

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