# 1948 8n, ignition coil (6 or 12 volt?)



## Dan_Newberry

I got the new distributor cap installed on my 1948 8n, and repaired the plug wires. The tractor has a 12 volt battery in it, and I had asked in a thread here a few months back whether that 12 volt battery would damage the points. 

I also have a 52 model 8n and it's been getting most of my attention (that I can spare for tractor work, that is), and the 48 had been on the back-burner until today.

The points on this 48 model look very good; no pitting, all was clean, as if it had been re-done recently. The fellow I got the tractor from had put plug wires on it, and the ends were not installed correctly... one wire had arced until that port on the distributor cap was blackened, and probably not firing. The tractor had been driven close to 20 miles when the man I got it from drove it home after he bought it.

The tractor was sputtering and missing a lot before I worked on it today.

Once the new distributor cap was installed, and the points were set correctly (there was almost NO GAP in those points; it's hard to believe it was firing at all), and I repaired the plug wires (they were Belden wires, in very good condition, only put together wrong)... the tractor started and runs good, all cylinders are firing now.

*My question is this: The ignition coil is a China made product, and looks to have been recently installed. But I can't tell whether it's a 12 volt, or a 6 volt. This tractor doesn't have the 12 volt alternator on it, it's still got the original generator. Previous owner put the 12 volt battery in it, and it has been used just like that for some time. *

Would a 12 volt battery ruin a 6 volt ignition coil? If so, would that mean I've likely got the 12 volt ignition coil? Is there a number on the coil, or some way of finding out whether it's a 6 or 12 volt? I'm trying to decide whether to convert this tractor to 12 volts, or just get a 6 volt battery and fix my generator (which may not even be broken, but I'm guessing it'll need freshening up).

Any help is appreciated.

Dan


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## sixbales

Howdy Dan,

If your coil is the old "square" type that mounts up front, it is a 6V coil. The points will burn in time yielding a shortened life. Normally, when you switch to 12V, you install a resistor in the coil circuit to limit current draw through the points and coil.


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## Dan_Newberry

sixbales said:


> Howdy Dan,
> 
> If your coil is the old "square" type that mounts up front, it is a 6V coil. The points will burn in time yielding a shortened lift. Normally, when you switch to 12V, you install a resistor in the coil circuit to limit current draw through the points and coil.


I appreciate the info. I have pretty much decided to get the 12 volt conversion kit, and just switch it over, and I think it comes with that resistor you mention.

I was looking online at front distributor coils for this tractor, and they list them in 6 volt and 12 volt (?)... so that's what I was wondering.


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## sixbales

Dan,

NH dealerships (Messicks) offer only the 6V version. See attachment. 

Do you have an ohmmeter? You could try measuring the primary winding of the coil. It should measure 2 ohms or less (cold) if it is a 6V coil, and 4 ohms or less (cold) if it is a 12V coil. I doubt that my ohmmeter is good enough to definitively identify which it is.


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## Dan_Newberry

sixbales said:


> Dan,
> 
> NH dealerships (Messicks) offer only the 6V version. See attachment.
> 
> Do you have an ohmmeter? You could try measuring the primary winding of the coil. It should measure 2 ohms or less (cold) if it is a 6V coil, and 4 ohms or less (cold) if it is a 12V coil. I doubt that my ohmmeter is good enough to definitively identify which it is.


Good info, yes I have a good meter (Simpson 260), so I will do what you say. I have a conversion kit on the way, it's costing 125 dollars. I will post again when we get the kit installed. I will of course keep the original 6 volt generator and other parts. A collector told me that this '48 is one of the straightest sheet metal tractors he has seen in some time, so it will be a good restoration project one of these days. 
Thanks a bunch for the help.

Dan


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## flagman12ron

I appreciate the info provided here but ihave a question, inorfer to check if the front coil is 6 or 12 v i understand about the ohms but how do you wire it up to determine the ohms. thanks


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