Put 12 volt hour meter on magneto M

BUCK CLAYTON · Jun 3, 2012

Want to put a 12 volt hr. meter on the 39M. Just finished overhaul work and want to keep up with hrs.I have 12 volt alternater Delco S 10 with single wire.I'm thinking a wire fm alt. to hr. meter, or an oil pressure switch in oil line to oil guage unit and hook wire fr. switch to hr. meter. I also think a wire fm ampmeter to hr. meter would allow it to run all the time. Not good. What is my best and cheepest solution. I need you alls help again. Thanks . Buck

JLE · Jun 3, 2012

I think your best bet is an oil pressure switch.

Bob M · Jun 3, 2012

Buck - If you are not a stickler for originality the cheapest is to replace the magneto kill switch with a DPDT toggle switch.

Wire one side of the switch to ground the magneto when the switch toggle is pointed down (your ignition "off" position). Wire the other side of the switch between the ammeter to the hourmeter so it supplies 12 volts to the hourmeter when the switch is "on".

Alternatively you can install an N.O. (normally open) pressure switch on the engine. Connect one side of the switch to the ammeter and the other to your hourmeter.

Key here is to get an N.O. pressure switch! Keep in mind most automotive oil pressure switches are N.C. (normally closed) - their contacts OPEN on sensing oil pressure.

BUCK CLAYTON · Jun 3, 2012

Bob and JLE. Thanks for come back. I already bought new mag switch, so that is out $40. I knew I didn't want the regular oil switch sending unit, But didn"t know the designation for switch that stayed open all the time . I'm going the oil switch way and want to thank you guys for setting me on the right track as usual. Many thanks. Buck

Nebraska Cowman · Jun 3, 2012

Your cheapest way would be to keep track of the hours in a notebook. I did that for oil changes for years on an old swather. The way my mother taught me was to make a string of 1s. when you got to four (1111) you struck a ling through for five and started over.

Jon Hagen · Jun 3, 2012

Most newer fuel injected cars / trucks have oil pressure switches with a set of NO contacts that power the electric fuel pump when the engine has oil pressure.

BUCK CLAYTON · Jun 4, 2012

Thanks Jon, Iv'e been looking for one . Should cut down on the looking . Thanks again, all of you. Buck

Put 12 volt hour meter on magneto M

BUCK CLAYTON

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JLE

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Bob M

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BUCK CLAYTON

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Nebraska Cowman

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Jon Hagen

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BUCK CLAYTON

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