Convert 6v farmall cub to 12v

Willy Hall · Jul 8, 2010

Thanx to you Mr.Janicholson I was able to make the conversion. However, I have had trouble with the oil pressure switch and I'll be the first to admit I don't know what the heck I'm talking about but why did you eschew a diode? Thanx again.

mkirsch · Jul 8, 2010

What oil pressure switch?

Cubs never had any oil pressure switch.

d. coleman · Jul 8, 2010

for a hour meter.

Dalex · Jul 8, 2010

You can use an oil pressure switch to turn on the alternater on a mag equiped machine. Then you don't need the diode.

Owen Aaland · Jul 8, 2010

(quoted from post at 20:20:39 07/08/10) You can use an oil pressure switch to turn on the alternater on a mag equiped machine. Then you don't need the diode.

If you have a magneto you don't need a diode anyway. The diode is only to prevent backfeeding the ignition coil so that it shuts off.

With a magneto there is no switch to supply voltage to the alternator to get it to start to charge. By using a two pole, normally open, pressure switch you can apply battery voltage to one side and connect the other to the light/excite terminal terminal on the alternator. That will allow the alternator so start to charge once there is enough oil pressure to close the switch. When the oil pressure drops the switch opens the circuit so the battery doesn't discharge when the engine is not running.

John M · Jul 8, 2010

You can use a Normally Open OP switch to keep the one wire alts from pulling power from the battery when the engine is off.

Owen Aaland · Jul 8, 2010

(quoted from post at 21:15:21 07/08/10) You can use a Normally Open OP switch to keep the one wire alts from pulling power from the battery when the engine is off.

Are you running all the charging amperage through the switch?

Janicholson · Jul 8, 2010

The oil pressure switch (from NAPA) will turn on when there is oil pressure, and off when there is none. (normally open switch with 1/8" pipe threads)
Putting a short nipple into the block, and a T on that, the oil pressure gauge can be supplied from one port of the T and the switch can be screwed into the other. The switch is connected to the starter switch on wire from the battery (big terminal end loop needed to fit the stud, small (blue colored insulator on the wire crimp)
the other terminal of the Switch connects to #1 terminal of the alt. I chose not to use the diode because the diode would allow continuous flow from the battery to the alternator trying to excite it when the tractor is shut off. The diode is used when there is a distributor ignition, and the ignition switch supplies exciter current control. Without the diode, the alternator will supply voltage to the coil (through the ignition switch terminal, and keep the tractor running). I hope this helps. Jim

Janicholson · Jul 8, 2010

I think (if I remember correctly) he is using a 3 wire stock 10SI. Jim

Convert 6v farmall cub to 12v

Willy Hall

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mkirsch

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d. coleman

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Dalex

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Owen Aaland

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John M

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Owen Aaland

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Janicholson

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Janicholson

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