The car in question is a '51 Ford (originally positive ground). How can I tell by looking under the hood if the car is still wired for positive ground? There is no battery in the car. Also, how can I tell if a starter has been upgraded to 12 volts? Or does the starter care about voltage? The previous owner had it rigged up with 2 batteries....6 volt to the charging system and 12 volt to the starter. He told me the starter was converted to 12 volt.
I don't wanna be a dick here but a search will bring up a fair amount of positive ground info. If the battery wires are there the big one is positive (battery post) and the small is negative. If the big one's bolted to the frame or the motor it's still positive ground.
Check the head lights. If they are still 6V then it has not been converted and it will still be 6V positive ground. If the headlights are marked 12V then you can assume that it is now 12V negative ground.
There is no particular way to determine positive or negative ground by looking at wires. To swap polarity, you just reverse the battery and repolarize the generator. Most old components don't care whether they're positive or negative ground. The Ammeter is one, and will read backwards if reversed. The radio is another, but I'm not sure what happens if reversed. Most guys keep their 6V starter and run it on 12 volts. By the way, the starter spins the same direction regardless of polarity.
My Hudson the battery cables are different size at the terminal, if your car has original 6V cables they only fit on the battery one way. You can force the smaller one on the bigger terminal, but they should slide on easily.
That's not the way it works. If the radio is hooked up backwards the DJs can hear you, and the light bulb will become a dark-bulb.
You must be the same guy that came into my grandfather's dealership years ago with a slow running clock in his car, and asked if they could put in a higher amp fuse to speed it up.
Well, the only time my original radio play is for 2 seconds when I turn it OFF. So can this be the problem?
So, if I polarize the generator with the battery hooked up either way, I'm good to go....with the exception of the radio.
All of the wiring/generator/regulator appears to be original. The previous owner added a 12 volt battery to help start the car. This battery was not wired to the charging system. I was told the starter was upgraded to 12 volt, but somehow I doubt that, and from what I've read, isn't necessary. I would like to keep it a 6 volt system, so I removed the 12 volt battery from the equation and put in one 6 volt. The starter turned very slowly but finally started the car just before I thought it sucked the battery dry. The ammeter didn't move it all and the battery cables were blazing hot. I disconnected the battery.
Could you tell me what the ammeter should be wired to? I'm not getting any movement at all. I'd like to chase it and see if the connections are bad/good.
When you installed the battery did u polarize the generator? If the generator is charging backwards the ammeter usually goes the wrong direction, and you could fry the regulator, wires, and battery. The starter can be rebuilt and will help getting it started, but you better have the rest of the system working correctly!
normally the starter will work with 12 volt..done it over and over..lights and guages are the problem...d32
Technically, the ammeter isn't "wired" with hard connectors and it isn't voltage sensitive either. On the Ford, the ammeter terminals are copper loops that the main wire passes through. The ammeter works by induction, that is the current passing through the loops is measured by the gauge. If the current goes backwards, the gauge reads backwards. When you reverse polarity, you have to pull out the wire and feed it through the loops in the opposite direction. Take a look under your dash panel and look for added-on voltage droppers at the backs of the gauges. You probably should look under there anyway because there's probably a fire under there waiting to happen. My old wires were like a bird's nest and the insulation was crumbling off. Solution: rip it all out and start fresh.
Your cables shouldn't be hot like that unless you cranked the hell out of that battery. 6 Volt starters are normally slower, you just gotta get used to it. Perhaps a bad starter or bad cables (or an out of tune engine) was the problem in the first place and this guy added boost voltage as a cure.
Cooter; You have to seperate the wheat from the chaff, ignore any response that suggests the polarity of the system can be reversed easily. They are pissin' in the wind. Then determine for sure before hooking up a battery to the system.
Well that was my original question. But, I gotta believe it's still positive ground since everything appears to be stock with the exception of the added 12V battery. How would YOU make this determination if there wasn't already a battery hooked up?
From what you have said it sounds like it is still 6V PG with the added 12V booster battery for starting. One of the biggest problems with 60 year old 6V systems is dirty corroded connections. Every dirty connection in the system adds resistance that was not present when the car was designed and built. Resistance equals heat and reduces the voltage that is available at the starter. Save yourself some problems and remove and wire brush all the connections including the ground cables. If you find a warm connection that is a sure sign of a dirty connection that is arcing and needs to be cleaned. The 12V battery was a lazy way of fixing a starting problem back when it was added. A bandaid and not a repair.
Holy crap ...my brains fried with all this, can't tell if I've got a 6v or 12 v brain, tried connecting an amp meter to my ear lobes...no responce
I'm going to polarize the generator, have the starter checked, and replace the cables this weekend. I'll post my progress. Thanks.
I have heard about the dual batteries before. What they would do is leave the car all wired up 6v positive ground. But they would use a 12v battery wired to the starter and have an additional starter button so that you could start the car with 12v and it would start easier but still have a 6v system. It a fix for people that believe 6v is not enough to start a car....Really just needed to fix the crappy connections and maybe some new connectors installed. http://www.btc-bci.com/~billben/12vboost.htm here is a link to explain how to do it.
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