[Farmall] Need Expert Opinion

[Jim Becker]

If "an external resistor that was in "parallel"  with the coil, not in 
series", and it is really a ballast resistor, it only proves one thing. 
Whoever wired it was an idiot.  Ignore everything you found on the tractor.

As far as I know, a 6-volt coil is a 6-volt coil, period exclamation point, 
period.  None that I am aware of used a ballast resistor.  If one did, it 
would be an even more unusual combination that nobody has parts for so you 
can ignore it.  The labeling on your new 6-volt coil was probably added 
because too many "thought they knew what they were doing" mechanics thought 
all ignition systems needed a ballast resistor.  Probably the same ones that 
think all systems are negative ground and put batteries in backwards.

If you told the NAPA guys it was a 6-volt ignition system and did not make 
it clear to them that you were using a 12-volt battery, they would have 
assumed you were using a 6-volt battery.  Of so, what they told you was 
correct.  They probably think you are working on what I called combination A 
while you are evidently trying to put together combination CC.  What you 
need to to is ignore and forget everything you found in the existing wiring. 
Hook it up the way I said in the last message.

This kind of mess is why I usually refuse to answer any questions related to 
a 12-volt conversion.  Who knows what may have been done in the past.  The 
mess usually can't be untangled unless you are looking at it in person.  If 
the guy that converted it knew what he was doing, he could have fixed 
whatever way wrong with the 6-volt system in the first place.  Doubling the 
voltage everything is operating on can mask an assortment of problems but 
rarely makes them go away.

Jim Becker

-----Original Message----- 
From: szabelsk at gdls.com
Sent: Thursday, October 27, 2011 11:27 AM
To: Farmall/IHC mailing list
Subject: Re: [Farmall] Need Expert Opinion

Jim,

That's were I started trying to figure out what was going on with the
original wiring that was on the H to start with.

The ignition system was wired with a 12V coil (don't know what kind it was
other than a Delco, and a really rusty one at that) and an external
resistor that was in "parallel"  with the coil, not in series. The wire
from the ignition switch went to the resistor on one side, and from that
same side, then went to the coil (+). The other end of the resistor was
grounded through it's mounting bracket. The coil (-) went to the
distributor.

Now when I went to replace the coil, I knew I needed a resistor in line to
drop the voltage. I brought a 6V coil and a new resistor to go with it. I
didn't realize that the old coil on the H was 12V, and didn't realize how
the old resistor was wired into it until I took it of and was ready to put
the 6V coil and new resistor in.

Since the new coil implies that I don't need an external resistor, I'm
confused as to whether or not I really need it. If I was putting the 6V
coil on a 6V tractor, I guess I wouldn't worry about it. But this is a 12V
tractor.

The Guys at NAPA said that the fact that I had a 6V ignition system
determined that I needed a 6V coil and didn't need the in-line resistor.
That's where I disagree with them. I don't think putting a 6V coil in a
12V system without an in-line resistor is a good idea. That also doesn't
agree with the fact that the H had a 12V coil to start with.

In your response you only mention three coils

---- 6 volt
---- 12 volt, no resistor required
---- 12 volt, resistor required

Are you saying that there is only one kind of 6V coil? Or are there two,
one with and one without a resistor required? The new one I have says no
resistor, but that wouldn't have been the case 50-60 yeas ago would it?
Aren't the coils that don't need a resistor later/newer technology?

Don't mean to contradict you or anything, just want to make sure I
understand everything and get things wired up right the first time. I
really need to have the H up and running this weekend.

Carl Szabelski



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