Ford 9N distributor problem

fredgraves · Jun 5, 2022

I am trying to get my 9N running. I have been working on it intermittently for a while. I saw a tutorial that worked on the distributor posted by the Gingell's in Michigan (farm tractor). At the start she discussed how to trouble shoot with a light probe on the top of the front mounted coil. With the switch turned on and the probe grounded, it lit up and stayed kit up as mine also did. Then she turned the engine over and and the light flashed as the points opened an closed. Mine did not flash, but was constantly on.
So I took the distributor and coil off. When I removed the distributor cap, I expected to see the points constantly closed. When I rotated the distributor shaft, the points did open and close. What is the deal? I might not be a mechanic, but even with a potentially incorrect gap (perhaps it is too wide) I think it should interrupt the flow and make the light flash.

Bruce(OR) · Jun 5, 2022

If your sure it's closing, glazed points and the wife nail file might be the next step.
IF you don't have a points file.

old · Jun 5, 2022

Dirty corroded burn points will do just that because they don't conduct power so they need t be cleaned and or replaced and gaped at 0015

Janicholson · Jun 5, 2022

The key here is that the points close to ground the coil. When they open they break the circuit going to the on off switch. This causes the
spark. Most 4 cylinder tractors stop with the points closed. The voltage going into the coil will be battery volts (or close) the points being
closed should show near zero volts from coil to points. Jim

Steve@Advance · Jun 5, 2022

I like to bench test those, that way it only has to be put back on once.

What you describe is the points not making connection. That is caused by the
contact surface being corroded or burned, or if new they may have an anti-
corrosion coating that needs to be cleaned off. Or there could be a bad wire
connection, bad connection from the coil, the points are improperly adjusted,
or the points are defective. These problems are much easier to correct on the
bench.

Setting the points to the correct gap is critical, be sure they are set and
tightened securely. Be sure the feeler gauge is clean. Good idea to clean
them and blot with a paper business card when done.

To bench test, using an ohm meter set on a low ohm setting, connect one lead
to the coil primary and the other to the distributor metal housing. You
should see the meter swing as you turn the shaft, opening and closing the
points. If you don't have an ohm meter, you can use the test light and a 9
volt battery. Connect one side of the battery to the distributor housing, the
other to the test light lead, hold the probe to the coil primary wire. The
light will come on when the points close, off when open.

wore out · Jun 5, 2022

Don't forget to tell him if the coiled ''spring thingy'' hanging down from the coil isn't making contact with the special brass screw beneath it or the copper strip from that screw to the breaker points has cracked/broken the result will be the same as if the points are not making contact.

fredgraves · Jun 5, 2022

(reply to post at 17:47:05 06/05/22) [
Thank you for your responses. they were all helpful.

I think I learned the most from Jim's, and it would have been nice if the tutorial I viewed had explained things the way Jim did. I guess I thought that that the open points meant that there was no flow to the plugs, but it is just the opposite. As I understand it now, when the points are open the spark is created which goes to the plugs. When the points are closed, the flow from the coil goes to ground and no spark is created for the plugs. Huh!

So varnish on the points could be a problem by not allowing the spark to go ground and creating a sufficient spark for running the engine when the points are subsequently open.

Access is a big problem with the alternator being in the way. If I take it out in order to put the distributor and the coil back in, I assume that I might be able to try to start the tractor without it being reinstalled.

Thanks again, Fred

Janicholson · Jun 5, 2022

Almost correct. Read up on Kettering ignition systems. The coil has two windings of wire in it. One is called a primary the other a
secondary. when the points are closed, the current flows through the primary making a magnetic field. This magnetic field saturates the
secondary windings, which have 1000 or more times as many turns of wire. transformers work by a moving magnetic field. When the points Just
open, the magnetic field collapses. This collapsing magnetic field passes through the secondary windings creating thousands of volts. This
voltage is directed to the plugs, in correct sequence, by the rotor. Jim

JMOR · Jun 6, 2022

(quoted from post at 21:21:46 06/05/22) Almost correct. Read up on Kettering ignition systems. The coil has two windings of wire in it. One is called a primary the other a
secondary. when the points are closed, the current flows through the primary making a magnetic field. This magnetic field saturates the
secondary windings, which have 1000 or more times as many turns of wire. transformers work by a moving magnetic field. When the points Just
open, the magnetic field collapses. This collapsing magnetic field passes through the secondary windings creating thousands of volts. This
voltage is directed to the plugs, in correct sequence, by the rotor. Jim

almost is correct" . One too many zeroes.

Janicholson · Jun 6, 2022

I could have thought about that zero more. I forgot that the primary allows a collapse voltage higher than battery volts! Jim

Ford 9N distributor problem

fredgraves

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Bruce(OR)

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old

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Janicholson

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Steve@Advance

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wore out

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fredgraves

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JMOR

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