[AT] Project Updates '49 A, '51 A, and '47 B (STEVE ALLEN)

Mon May 11 07:35:51 PDT 2020

Cecil,

My Farmall H, 4 cylinder, was converted from 6V to 12V by the PO. I use a coil with an internal resistor.

 I remember reading some articles on doing a 6V to 12V conversion when I had to replace the coil at one time and needed to figure out what I needed for the new coil. My understanding, if I remember correctly, is that without the internal resistor the points will burn out a whole lot quicker. 

Carl

----- Original Message -----
From: Cecil Bearden <crbearden at copper.net>
To: at at lists.antique-tractor.com
Sent: Mon, 11 May 2020 10:12:53 -0400 (EDT)
Subject: Re: [AT] Project Updates '49 A, '51 A, and '47 B (STEVE ALLEN)

A resistor in the coil is only needed for 6 & 8 cylinder engines.   The 
coil does not get hot enough on 4 cylinder engines to require a 
resistor.  You can remove the coil from the magneto and drill holes in 
the magneto case to run the battery and coil wire out of the case and 
also the high tension coil wire into the magneto to use the distributor 
terminal.  It would be easier if a distributor ignition is available for 
the engine.  I think Tractor supply used to have these.  I would contact 
All States Ag Parts to see if they have a used one.
Cecil

On 5/11/2020 9:00 AM, szabelski at wildblue.net wrote:
> Steve,
>
> All you need to get spark is something to generate the current that flows to the spark plugs through the timed opening and closing of the contacts. This can be done with a magneto or a coil.
>
> You can replace the magneto with a coil by wiring the coil to the battery, “+” to positive and “-“ to negative. Then ground the coil body to the chassis in some manner and plug the magneto wire into the coil.  If you do a search on-line you can probably find u-tube videos that show how people have done this for one reason or the other. The only question that I can’t answer is wether or not you will need a coil with an internal resistor, or you will need an external resistor. I believe you will need one with an internal resistor, but not really knowing you machine, I can’t say for sure. With all the various coils out there, you may want to talk to somebody like your local NAPA to see if they recommend a specific coil. You may be able to get by with whatever coil you have laying around, but can’t say for sure that it will be optimum operation.
>
> If it fires with the coil, then I would say you have a magneto problem. If it doesn’t, points, condenser, rotor cap, or spark pug wire are suspect, maybe a ground somewhere in the circuit.
>
>   Keep in mind that with a coil installed, your existing kill switch is no longer in the circuit, so you will need to be able to pull the magneto wire out of the coil to shut down, or wire a kill switch into the connection between the battery and the coil to disconnect power to the coil.
>
> Good luck.
>
>
> Carl
>
>
> ----- Original Message -----
> From: STEVE ALLEN <steveallen855 at centurytel.net>
> To: at at lists.antique-tractor.com
> Sent: Sun, 10 May 2020 20:00:36 -0400 (EDT)
> Subject: Re: [AT] Project Updates  '49 A, '51 A, and '47 B (STEVE ALLEN)
>
> OK, two quick updates that I hope will generate more ideas.
>
> '51 A:
> We're finding a lot of loose, rust scale in the tank.  When I say a "lot," I don't mean the bottom is covered with it,  But, dangling a flashlight inside, I saw what appeared to be some "stuff" around the outlet.  So we used magnets on extendable rods, and pulled out a couple ounces of scale.  Finally, the magnet came out clean.  Ran the tractor.  More starvation.  Put the magnet back in, more loads of scale came out.
>
> The bottom of the take looks pretty clean, but there are small, dark patches that I think represent some more or at least places where the coating (if any) is worn.  did these tanks come with a coating?  Anyway. the fuel flow seems much better as we reduce the amount of scale in there, but we have more to go.
>
> Is there a better cleaning process?  I seem to remember someone suggesting a powerful magnet near the outlet to catch such crud.  Or am I remembering something else??
>
> '49 A:
> No spar4k from the mag, either using the plug or, per the manual, a wire with an 1/8" gap to ground.  No spark either one.  I checked continuity on the points per Dean.  My meter read .5 Ohms with the points closed and .7 Ohms with them open (separated by a thin piece of cardboard).  I seem to have good continuity on the cap; visual inspection shows no cracks, but will have to check that further.  No continuity between the interior contacts and the center contact, at least.  No kill switch or other possible ground through the cap or the case.  Rotor clean and checked for proper continuity:  center button to contact has continuity; no continuity between center button and the metal plate inside which touches the shaft.
>
> Carl:  I don't quite get what you mean by wiring with a coil replacing the mag.  Could you explain more?
>
> Dean:  used some very fine sand paper on the points to clean them.  .5 Ohms with them closed; .7 Ohms with them open (separated by cardboard).
>
> I have another mag, but it hasn't been used in many years; a new cap is about $60+ shipped; would prefer not to order unless I am sure the cap is bad.  Do the Ohm readings on the points suggest a problem?
>
> Thanks again, all!
>
> The "original" Steve Allen
> Doing my part to keep the list active.
>
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