[AT] IH H4 Magneto-no spark

[Gene Dotson]

    Good advice Doug.

     I have gotten a couple sets of points that had apparently been on a 
shelf for a while. No continuity between the contacts. Checked ohms on each 
side of contacts and read open when points were closed. The supply of a lot 
of these parts are getting scarce and many of the current parts have been in 
the system a long time and the tungsten contacts have oxidized. What I use 
and would be a good investment is a contact burnishing tool. It is coated 
with fine diamond dust and will remove the hardest tungsten oxide and leaves 
a very smooth surface. Comes in a little plastic case and is about 3 inches 
long and 3/8 inch wide. Surface looks very smooth, but lasts a long time.

            Gene



----- Original Message ----- 
From: "Doug Tallman" <dtallman at accnorwalk.com>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Monday, May 30, 2011 4:05 PM
Subject: Re: [AT] IH H4 Magneto-no spark


> Al, Did you clean the new points good. Maybe even some real fine sand
> paper. They can get a film just from setting. Get the ohm meter out. You
> should have somewhere in the 5-10K ohms through the secondary to ground.
> Usually 1-2 ohms through the primary. Make sure none of the wires are
> touching the case. Doug T.
>
>
>
> Al Jones wrote:
>> Started tinkering on the white Super A this afternoon.  Magneto impulse 
>> clicks when you hand crank the engine, was hoping I could just rub the 
>> points a little and make fire.  When I got the breaker cover off, I saw 
>> the leaf spring on the moving point had broken.  I had a new point and 
>> condenser set lying around, so I went ahead and took the mag off and 
>> replaced all that.  Condenser was tricky but I got it.  Had a time 
>> getting the screw loose on the stationary point but I got that apart and 
>> since I couldn't find my feeler gauge anywhere, I used a piece of the 
>> cardboard boxtop to set the points.  Backwoodsy-hillbilly but the points 
>> connect and break so I felt like that was in the ballpark.
>>
>> Long story short I still have no spark.  The inside of the distributor 
>> cap looks pretty corroded, so I tried pulling the wire from the coil 
>> cover to the dist. cap and trying to get a spark from there (trying to 
>> arc it off the side of the engine block) but still no spark.  The 
>> connection in the coil cover looks pretty good, and the inside "tab" that 
>> touches the coil itself is bright, shiny copper. (The coil cover could be 
>> original.  It has the old IHC trademark instead of the IH "man on a 
>> tractor" logo)  I did knock the glaze off the dimple on the coil, and on 
>> the rotor button.
>>
>> The only thing I can think of is the coil itself.  Looks like given the 
>> condition of everything that I could get some spark from the coil 
>> terminal.  What else should I look for?
>>
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