dmdec Posted September 4, 2015 Report Posted September 4, 2015 Hello I am a new member who has just acquired a new barn find 1951 Cranbrook club coupe. I couldnt be happier, this thing runs like new (well almost). I have a few electrical questions though. When I picked up the car, the fellow had it hooked it up as neg. ground to the battery. Car turned over fine, so when I got it home, I put in new plugs, charged the battery, hooked up the fuel to a gravity feed can and walla, the car started right up and purrs like a kitten. I ordered the owners manual and found out the car should hooked up as positive ground. Now I am confused and have many questions. Here goes: 1. Should I hook it up the right way as positive ground, will I harm any thing ? 2. What would be the harm in leaving it as is ? It seems to run great with negative ground. 3. Can they run either way ? (apparently so). 4. Are there any long term effects if I just leave it negative ground ? I heard that a battery can be "fooled" into accepting a charge in reverse order, maybe this is whats going on ????. Should just buy a new battery and hook it up positive ground. There is no evidence that someone changed it to neg. grd. How would I tell. Hope someone can help me. Thanks abunch Dennis in Mich. I plan to make a econo. driver out of it. Maybe new paint and chrome. Thanks again Quote
Don Coatney Posted September 4, 2015 Report Posted September 4, 2015 Has your car been converted to 12 volts? Does the charging system work as is? Quote
Plymouthy Adams Posted September 4, 2015 Report Posted September 4, 2015 as Don asked, is the unit still 6 or converted to12...am assuming it is still 6 as you made no reference to charging it 12 volts...no bid deal if positive or negative ground. as long as the polarity on the ammeter is changed to reflect the current flow. Another thing is the swapping of the coil wires due to the way it is internally connected to ground....but at the lower spectrum of RPM's you will be turning this engine..you would never see a significant benefit from this..as you can easily test the battery for reverse charge with a meter...or in your case if you connected the polarity of the charger correctly it would have only charged in internally polarity is correct. Quote
Ulu Posted September 4, 2015 Report Posted September 4, 2015 I never heard a battery could be "reverse charged." Lots of people have totally failed to charge their battery, though, when they failed to polarize their new generator. Quote
Don Coatney Posted September 4, 2015 Report Posted September 4, 2015 I never heard a battery could be "reverse charged." Lots of people have totally failed to charge their battery, though, when they failed to polarize their new generator. I once observed such a battery. It was totally discharged until completely flat then charged with reversed polarity. Quote
Jerry Roberts Posted September 4, 2015 Report Posted September 4, 2015 If you don't know how to tell a 6 volt battery from a 12 volt battery , count the caps . 3 for a six volt , 6 for a 12 volt . What these guys are getting at ; if you are running 12 volts , you are going to have negative ground . If you have a 6 volt battery and you want to stay negative ground , that is OK too . Quote
Ulu Posted September 4, 2015 Report Posted September 4, 2015 . . . if you are running 12 volts , you are going to have negative ground . . . Maybe, and Maybe not. I had a 12 volt english car that was + ground. Quote
Niel Hoback Posted September 4, 2015 Report Posted September 4, 2015 My son has a 66 Jaguar that is 12v positive "earth". Quote
Ulu Posted September 4, 2015 Report Posted September 4, 2015 (edited) Is the battery under the offside wing? (Mine was a '64 MG Midget.) Edited September 4, 2015 by Ulu Quote
dmdec Posted September 4, 2015 Author Report Posted September 4, 2015 OK guys thanks . Got some good info. To Don and ALF.. The car is stock 6 volt. Never converted. Im getting the impression the car will run fine either way. Please confirm that is true. One thing I forgot to mention. All seems normal like I said, except for one thing. The AMP meter runs backwards. In other words, when you rev the motor, it goes to the left side or (-) side. Other than that all appears normal. Keep the anwsers coming guys, THANKs Quote
dmdec Posted September 4, 2015 Author Report Posted September 4, 2015 One more thing. If I want to set it up as positive grd. with a new battery, do I need to do anything ? Quote
Plymouthy Adams Posted September 4, 2015 Report Posted September 4, 2015 In post 3 I confirmed it would do good either way..I also pointed out the facts that would show it as not being right...the ammeter as you described is one fact I pointed out.. Quote
Don Coatney Posted September 4, 2015 Report Posted September 4, 2015 Reverse your battery cables and drive it like a rental. Quote
Jerry Roberts Posted September 4, 2015 Report Posted September 4, 2015 Maybe, and Maybe not. I had a 12 volt english car that was + ground.on We are talking about a 1951 Cranbrook . Quote
Plymouthy Adams Posted September 4, 2015 Report Posted September 4, 2015 We are talking about a 1951 Cranbrook . that apparently is not wire right either....lol Quote
Ulu Posted September 4, 2015 Report Posted September 4, 2015 OK guys thanks . Got some good info. To Don and ALF.. The car is stock 6 volt. Never converted. Im getting the impression the car will run fine either way. Please confirm that is true. One thing I forgot to mention. All seems normal like I said, except for one thing. The AMP meter runs backwards. In other words, when you rev the motor, it goes to the left side or (-) side. Other than that all appears normal. Keep the anwsers coming guys, THANKs It runs either way, but does your heater fan spin backwards? Radio polarity an issue? I never ran the tube radios in my old cars. I kept them for looks and hid a modern 100 watt radio under the seat. Quote
greg g Posted September 5, 2015 Report Posted September 5, 2015 I don't think the radio care. the humming you hear when you turn on those old units is the vibrator. It essentially taked the DC supplied by the car and changes it to AC for the radio circuits. So it probably doesn't matter. The one thing to double check is to see which coil lead is going to the points ternminal on the distributor. Should be ign to neg, pos to points. Quote
Ulu Posted September 5, 2015 Report Posted September 5, 2015 We are talking about a 1951 Cranbrook . that apparently is not wire right either....lol Or at least is 64 years old. It could have had anything in it. Anyhow, I was just saying that just because it was 12 volts doesn't mean it was converted to neg ground too. (Doesn't mean it wasn't either.) Quote
dmdec Posted September 5, 2015 Author Report Posted September 5, 2015 (edited) OK Don, I think your suggestion is a good one, but wait until I buy a new battery just in case the one in the car is reverse charged. Ill get a multi meter also to answer that question. Thanks a bunch. Edited September 5, 2015 by dmdec Quote
Andydodge Posted September 5, 2015 Report Posted September 5, 2015 The ammeter going backwards indicates that its had its polarity incorrectly changed..........I'd be making it positive earth as it should be when a 6volt system and watch the ammeter again........as for what the pommies/English/kippers do I'd disregard any reference to them in a mopar conversation............lol.....6volt equals positive earth.....andyd 1 Quote
_shel_ny Posted September 5, 2015 Report Posted September 5, 2015 Starts, and runs. Why do you need a new battery? Quote
Plymouthy Adams Posted September 5, 2015 Report Posted September 5, 2015 I read that similar fashion Shel..but then he mentioned using a volt meter so I assumed he will test polarity first and only if in error..would buy a new battery.. Quote
_shel_ny Posted September 5, 2015 Report Posted September 5, 2015 I read that similar fashion Shel..but then he mentioned using a volt meter so I assumed he will test polarity first and only if in error..would buy a new battery.. Logical, but I read it as will buy a new battery just in case it is charged reverse Personally I would just install the battery the right way. My thought is PO just stuck it in backwards Quote
Plymouthy Adams Posted September 5, 2015 Report Posted September 5, 2015 I agree Shel...can only go by comments when not on site to inspect.. Quote
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