In Reply to: broke 860 posted by Bob Thomas on November 08, 2018 at 16:42:45:
Realize that just because a guy says he is a seasoned ‘mechanic’ does not mean he knows and understands these old FORD Electrical systems. ALL FORD vehicles used the 6V/POS GRN system, not just tractors. Later 50’s began using 12V with diesels and then guys started putting 12V batteries in their tractors. Swapping out batteries does not constitute a 12V switch over job. There are other factors as well, mainly, the generator and voltage regulator get removed from the circuit and a 12V alternator is then used. There is no resistor in the OEM 600/800 system. You can take your battery and alternator to a qualified starter shop who knows these old Ford systems and get them tested first. Also, it is a fact that 99.98% of all non-starting/non-running issues with these old Fords is due to the wiring being incorrect, and the majority of those are from a mucked up 12V ‘conversion’ being done by someone with no clue on what they are doing. There are but handful of correct ways to switch over from 6V to 12V and a hundred ways to switch it wrong. Here is a diagram of the OEM 6V system as a guide. Get an I&T F-020 Manual and use as a guide as well. Thee are plenty of qualified guys out there -just look harder. I suggest you go around to the starter/alternator shops and find one who is knowledgeable on old Fords.
FORD 600/800 6V ELECTRICAL DIAGRAM: