Topic: 34 ford battery polarity

pajmward	-- 12-19-2020 @ 6:09 PM
	Hi How difficult is it to change polarity from Positive earth to negative earth on a 34 Ford. I am having trouble getting hold of a 6v positive earth fuel gauge. I have a 6v neg earth gauge but it will not work on the pos earth system. I am thinking I would only need to change battery terminals, coil wires, and generator polarity. Is this correct?
51woodie	-- 12-20-2020 @ 6:26 AM
	Can you not just reverse the leads on the gauge? I installed a 6V electric fuel pump on my '46 coupe, and the instructions for use in a POS ground system, was RED to ground and BLACK to power.
juergen	-- 12-21-2020 @ 5:49 AM
	Are you sure the gauge is polarity sensitive? The early Ford types were originally vibrating points type where the current was on and off as it heated a bimetal strip whose tension was a function of the float and then pointer movement. Some repro senders used a variable resistance (set by the float) to maintain a variable current. Neither the points nor the resistor cared which direction the electrons flowed.
pajmward	-- 01-10-2021 @ 11:40 PM
	The gauge will only work with neg earth, I get no reading when pos earth/
TomO	-- 01-11-2021 @ 6:59 AM
	You have an aftermarket electric fuel gauge or one from a non-Ford make. They usually are the resistance type where there is a variable resister in the tank unit and a bi-metal strip in the gauge unit that heats up and bends. The bending action moves the needle. This type can work with both POS and NEG grounding depending upon the connections. Your best bet is to find a 1936 Ford gauge cluster and adapt it to your 1934 Ford. To change the polarity of the car, you will have to have a new coil and cutout for NEG ground and polarize the generator. If you have any accessories, their polarity needs must be accommodated. Tom This message was edited by TomO on 1-11-21 @ 7:03 AM

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