Wiring the gauges on my F1 and it occurred to me that polarity is now reversed from stock. (6V pos. ground to 12V neg. – and I already have the voltage drop handled with a 60's bronco IVR) But as I'm researching the swap I see some saying you HAVE to swap poles at the gauge, and an equal number of folks saying "Nope, early Ford gauges DO NOT CARE ABOUT POLARITY." So... which is it?
Well, the "amp" gauge doesn't have poles. And I should have mentioned I'm not running that one – I removed it and added a second temp. gauge so I could have one for each head. I'm just looking for some first hand knowledge concerning the polarity of early Ford gauges. Talking fuel, temp, and oil pressure.
Your original gauges should be King Seeley bimetallic thermal gauges with points style sending units. There should be a fair amount of discussion here or on the Ford Barn of their operation. They are not polarity sensitive and your ammeter should be inductive. What are you using for sending units?
If you did have the original '33---much later Ford ammeter, the wire has to run through the inductive loop in the opposite direction so charge and discharge show correctly! Other Ford gauges, not polarity sensitive. They need their own sending units...most other type snders work by resistance and are no good here.
Ahh, so it looks like I am good to go with temp and oil pressure then. I have a small pile of original single pole temp sending units that I can test with boiling water and an ohmmeter(?). And I'll just plug in an oil sender in and take my chances there. (since this is the same flathead that has survived near zero pressure I think I'm covered) This leaves fuel. Realizing now that since I went with a 60's Mustang tank between the frame rails I've lost the stock sending unit. Wonder how that's going to work out?
Truck. Plenty of room for a jerry can. Be sure to use real military with a traditional date stamp, of course...
If you are 12 volt using a pulse type IVR, you can use rheostatic type senders. That is what Ford did post 1956. You may run into some calibration issues using a pulse type IVR and the original pulse type senders. If you have the Mustang tank and IVR, just use the Mustang fuel sender, it is the correct ohm range.
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