New one for me, Electrical question

tracto-man · May 17, 2016

Got this beast of a 2n all rewired with a 12v system, wired per Jmors wiring diagrams like I always do. Last night was about to put the hood back on., and decided to run
it one more time just to make sure everything was working. Wouldn't fire so I checked and no spark. Grab the test light and find it's not getting through that white
resistor. Tough it and it's REALLY hot. Turned everything off and unplugged it. looks fine to me. Should I be chasing down a short or just replace the resistor?

Bruce (VA) · May 17, 2016

Why are you even using an additional resistor?

You've got the OEM ballast resistor. That and a 12v coil is all you need. See tip # 30.

And you might already have a 12 volt coil; measure it to find out. 2.25 ohms or more, it's a 12v coil. 2 or less, it's 6v.

But, if you don't want to buy a 12v coil, at least get the proper resistor to match the 6v coil.

If the coil is 1 ohm & the OEM ballast resistor is 1 ohm, you need an additional 2 ohms of resistance in the circuit. More & it will be hard to start; less, and your coil suffers.

See why it's easier to just get a 12v coil?
75 Tips

tracto-man · May 17, 2016

Thank you much Bruce. It is a 12v coil. Don't know why I put that resistor on there. Probably just 'cause that's the way I do most of em, even though the other ones I've done didn't have the original resistor.

Steve Oller · May 17, 2016

It's easier to leave it a 6 volt system.

Bruce (VA) · May 17, 2016

" even though the other ones I've done didn't have the original resistor."

So, w/o the OEM resistor, what was the value of the ceramic resistor you added in the others? 4 ohms?
75 Tips

JMOR · May 17, 2016

(quoted from post at 13:37:24 05/17/16) It's easier to leave it a 6 volt system.

es, Steve, because with that battery laying on its side, all the acid will run out and make a big mess. :wink:
Actually, it is always 'easier' to do nothing than something. :wink:
He might still have a short or points slipped closed if res got hot real fast & no start.

souNdguy · May 17, 2016

Based on your text, I'd say your test lamp is bad or you are using it wrong.

If the white resistor is getting hot, it has current flowing thru it, it is dissipating heat / wattage and will have a voltage drop across it. given that there is a resistor ahead of it, and a coil primary after it, that means that your test lamp probe should 'see' voltage on either side of it, whether points open or closed.

since you said nothing was getting thru.. I'm guessing you were using the probe wrong.

as was said.. if you have a 12v coil.. try just with the dash resistor...

post back.

tracto-man · May 18, 2016

Yanked out the white ceramic thingy and it fired right up. Thanks all for your help.

tracto-man · May 18, 2016

I honestly do not know. Earlier 9n's that already had 12v, just needed rewired, and tuneups. hey had 12v coils too.

Ken(Ark) · May 18, 2016

As a side note , since I started gutting the square coils , removing all resistors , and adding a Napa ic14 or equivalent 3.25 ohm round coil, I have had zero ignition problems . I do use heavy duty toggle switches , no keys .I figure that anyone that wants to steal a tractor could probably hot wire it but when I need it the key is somewhere else , unless you leave the key in it then what is the point ?

With a round coil it is easy to clip on a dwell meter . You can verify that the points are working and gapped right . No need to pull he distributor annually to manually guess if it is set correctly .

FlatFenders · Jun 6, 2016

I just replaced the points in my 1948 8N, front mount distributor, with a solid state module. At the same time, I ran a new wire from the negative terminal (where the condenser would go) so I can measure engine r.p.m. with a normal tachometer (tractor is now 12 volt negative ground). Now that I can also measure dwell, any idea what it should be? In an archived post, someone stated that dwell on a side mount distributor was 55 degrees and he said you can't measure it on a front mount . Well, now I can?

JMOR · Jun 7, 2016

(quoted from post at 00:35:07 06/07/16)
I just replaced the points in my 1948 8N, front mount distributor, with a solid state module. At the same time, I ran a new wire from the negative terminal (where the condenser would go) so I can measure engine r.p.m. with a normal tachometer (tractor is now 12 volt negative ground). Now that I can also measure dwell, any idea what it should be? In an archived post, someone stated that dwell on a side mount distributor was 55 degrees and he said you can't measure it on a front mount . Well, now I can?

ervice Training Manual shows 35 to 38 degrees. The guy that said 55, likely based his WAG on a 'theoretical' 2/3 X 90 =60, but with 'all well' distributor and 0.015" point gap, the SVC Training Manual 35-38 will be the best you can obtain & sometimes less. BTDT

oldtanker · Jun 7, 2016

(quoted from post at 10:37:24 05/17/16) It's easier to leave it a 6 volt system.

Yep, be easier to have just a land line phone and no computer either! What's wrong with improving a working as opposed to a show tractor? Alternators are much more reliable than a generator and voltage regulator, 12 volt batteries are cheaper too. Other than for the purist I can't see the down side to a conversion. Last set of points, Standard brand, didn't match up by about 50%. Because I was in a rush I failed to notice it and they lasted about 10 hours. Now that tractor is not only 12 volt it's electronic ignition too. Heck, I'm going to buy a 600 series Ford. Basket case, everything is there, comes with decent loaded tires. Guess I'm supposed to drain the tires because it didn't get shipped from the factory that way? As that one goes back together guess I shouldn't paint it either because todays paints are not what the tractor was painted at the factory? It's getting paint, 12 volt conversion and EI too.

Rick

Ken(Ark) · Jun 7, 2016

I just replaced the points in my 1948 8N, front mount distributor, with a solid state module....... Now that I can also measure dwell, any idea what it should be?

How do you adjust the dwell on an EI unit ?

JMOR · Jun 7, 2016

(quoted from post at 21:27:10 06/07/16)

I just replaced the points in my 1948 8N, front mount distributor, with a solid state module....... Now that I can also measure dwell, any idea what it should be?

Click to expand...

How do you adjust the dwell on an EI unit ?

lter spacing between module & magnet.

New one for me, Electrical question

tracto-man

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Bruce (VA)

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tracto-man

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Steve Oller

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Bruce (VA)

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JMOR

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souNdguy

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tracto-man

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Ken(Ark)

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oldtanker

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Ken(Ark)

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JMOR

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