Farmall 450 Coil Voltage

Anonymous-0 · Aug 22, 2013

Did the 450 have a 6V coil with resistor or a 12v coil?

Pete_5959 · Aug 22, 2013

Eraly 450 gas had a 6 volt ignition. Later production switched to 12v and used external resistor and "probably same coil?". The LP and Diesel tractors were 12v with ext resistor.

mkirsch · Aug 22, 2013

I think that IH used a 6V coil with external resistor right up through the 56 series. Might be wrong on that, though.

The way I understand it, there was an extra tap off the starter solenoid that shot straight 12V to the 6V coil during startup. This gave you a much hotter spark than you would normally see while the battery was being stressed by cranking.

D Slater · Aug 22, 2013

Gasoline serial 11084 and higher came 12 volts with resistor and also used a different magnetic switch on the starter and a extra wire in the harness to bypass the resistor when starting. IH did sell complete kits to change 300 to 450 tractors that came 6 volt over to 12. 12 volt LP used a resistor serial number 11093 and higher. 12 volt diesels used a resistor 13491 and higher. LP and diesel below the above serial numbers were originally 12 volt and no resistor.
That's how they came but lots of things are changed after 50 plus years.

Anonymous-0 · Aug 22, 2013

The tractor is 12 volt. If I put a 12 volt coil on it do I need to use a resistor?

John G. Hasler · Aug 22, 2013

> If I put a 12 volt coil on it do I need to use a resistor?

No.

Mark in Upstate · Aug 22, 2013

My '57 450 is 12 volt with a resistor.

Hugh McKinney · Aug 22, 2013

I think that's right. That's what my 450 LP has: 12 volt system, 6 volt coil with resistor, and extra wire to coil from starter solenoid giving 12 volts to coil during cranking.

John T · Aug 22, 2013

Nope, if its a 12 volt coil you want to feed it 12 volts NOT 6 WELL DUHHHHHHHHH if you use a voltage dropping (12 to 6) ballast resistor ahead of the coil, then you only leave 6 volts for a coil designed for 12. It still can spark albeit weak.

John T

Owen Aaland · Aug 22, 2013

The only machines that I recall IH using 12 volt coils on were Cub Cadets and a few skid steer loaders.

There may have been some Japanese or European built tractors that use a 12 volt coil but all US built tractors used a six volt coil with a discrete resistor or a resistance wire built into the harness between the ignition switch and the starter solenoid.

D Slater · Aug 22, 2013

I'm thinking IH used a coil on 400 LP and early 450 LP and some diesels used the same coil with a 12 volt battery and no resistor or resistance wire. Some diesels used other coils with or without a resister. IH changed there minds on the diesel coils a few times and recommended a change in some coils after they were sold. Think some were 6 volt without a resister because they didn't think they would run that long on gas. If I remember correct a resistor wasn't originally used on the diesel engines of that engine family until sometime during 450 production.

pete 23 · Aug 22, 2013

The 450 diesels did use 3 different coil setups. One was 12 volt coil, one was 6 volt coil with external resistor and then they dropped the resistor and still used a 6 volt coil. Put more new coils on those diesels than all the gasoline tractors combined. They went to the straight shaft with no advance and made a hard starting tractor even harder so they left off the resistor and used the 6 volt coil alone. Going through that cut off switch on the manifold they didn't use a bypass wire coming from starter solenoid to go around the resistor for starting. That is the way I remember it anyway.

Farmall 450 Coil Voltage

Anonymous-0

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Pete_5959

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mkirsch

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D Slater

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Anonymous-0

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John G. Hasler

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Mark in Upstate

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Hugh McKinney

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John T

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Owen Aaland

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D Slater

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