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General Tech Positive Earth?? Very confused. A little help?

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Paul Romans

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Alright, I'm out of my depth here. Bought a '63 Herald last fall, it was hooked up for Negative earth. Haven't run it much, just around the yard. But since I've had it, both the battery and coil have gone bad. Battery boiled over and left acid all around. The coil went dead after I'd washed the car, including under the hood. Otherwise, everything else seems to work; starter, headlights, wipers. The wiring is a 60 year-old nightmare, with extra leads running everywhere (GNDN) and the correct wires just twisted together and (maybe) some tape on them. Still has the old Lucas generator.

Checking the manual today, I see it's supposed to be POSITIVE earth. Ouchy. So, first, how to confirm? Do I just switch the battery terminals around? What will happen? A little guidance please before it catches on fire.

Thanks, Paul
 
Define "confirm"! Seriously, whatever "earth" it is depends entirely on which battery terminal goes where. Truth is, it really doesn't matter unless you have polarity-sensitive components (like a radio or "power port" for a cell phone, etc.), in which case you'll want to stay with the Negative earth. On cars of that age, the other components don't care and won't be affected, although, in an ideal world, one should switch the two low-tension wires on the coil.

Switching from one earth to another usually also involved re-polarizing the generator. However, if most everything is working now, just leave it as is! :D
 
No. The generator would need to be repolarized to positive ground, and I think the low tension wire for the coil would need to be shifted. Also, any electrical accessories, like a modern radio?
Many owners shift to negative ground (earth) just to “modernize”. One of your car’s DPO must’ve done that too. I did not, happy to pay a little more for my Pertronics points, alternator, and LED bulbs. I just think it’s cool.
Unless you want to restore your Herald to original, I’d recommend just keeping it as it is. Do not just reconnect the battery to positive ground.
Now, about your wiring. I’d recommend getting a new harness from Britishwiring.com (unless you are planning a complete restoration at some point) and replace it this winter.
There is plenty of debate on here about pos vs neg earth. Assume you have a wiring diagram? Keep us posted…. Jim
 
I am confused by the above answers. IF EVERYTHING IS WORKING--- is not true. Why did the battery "boil over"?
It sounds to me like there is a problem. Likely with how the system is connected to the battery. Positive vs negative.
Charley
 
Thanks everyone for the feedback. More info: No modern accessories. No radio, cell port, etc. Trying to keep it original. Headlights work, and I tried the wipers just to see, but haven't used them since. It's a Herald 1200, but somewhere in the dim past a 948 engine was substituted, along with a home-made replacement dash with lotsa extra gauges and switches. The wiring is full of mystery leads that once did something but now Go Nowhere, and Do Nothing (GNDN). I remember now that the seller told me to bring a battery, so I probably hooked it up wrong first time.

It does start and run great, and I don't wanna mess that up, but I haven't run it more than an hour total since I bought it last September. The generator is going into the shop for a rebuild, I'll see what he says. What about the starter?
 
They work regardless of polarity, so no prob.
so did you use a garden hose in the engine compartment? As Charley pointed out, we still haven’t IDed the battery issue…
 
Something is definitely “broken”. Given the kludge of wires, I think a new harness is your best bet. Pick either negative or positive earth, make sure the generator is correctly polarized (I assume doing this twice - if it was done when originally converted - won’t hurt anything???), and go to town with fresh wires.

The wiring diagrams available from advance auto wire are quite good. There are a few errors and omissions, mostly obvious when you are doing the wiring; you’ll notice incomplete information on the diagram, and an internet search will provide you the needed knowledge. Point being, the hardest part of rewiring is figuring out if the harness should start in the cabin and be pulled through to the engine (yes - bulbs of dashboard won’t fit) or pull wiring in from the engine.

Clean grounds are vital. Use sandpaper, a dremel, and I’ve seen a nifty tiny round brush that attaches to a drill.

You may need to add some bullets and connectors. I bit the bullet (pun intended) and bought a crimper, but you can solder or borrow one just as well.

Note, the new harness might have incorrect bulb fittings in the dashboard. Keep the original harness in case you need bulb sockets.

I am a mechanical guy, electrics are not my strong suit. So my answer is to follow the book and make everything “perfect”. But that’s just me; your mileage, experience and knowledge may vary! Good luck!
 
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Thanks um, "Popeye / Darth Vader" (that's pretty bi-polar, but whatever works dude).

Jim, I did spray the old dirt under the hood trying to get it clean, and I sprayed away the acid around the battery shelf. Tried not to get everything wet, but the coil did die minutes after.

I have the original workshop and the Haynes manuals, so good wiring diagrams are in hand. There are wires dangling in the engine, the dash, in the trunk, it's a mess. All the old connections are poor, if not shot, so by the time I get it all sorted, I'll have a new harness anyway. I want to pull out the new dash and go back to the original layout and electrics. Somebody once added a toggle switch to turn on the instrument lights.

Oh, oh! Another thing! The seller bragged he'd installed a new voltage regulator. There is a new-looking one sitting loose on the shelf next to the clutch master. No idea if it's correctly wired up. Still investigating.....
 
Paul Romans said:
The seller bragged he'd installed a new voltage regulator.
Click to expand...
If this is one of the old style mechanical regulators, it needs to be adjusted to work properly, even if it's brand new. It could be overcharging the battery. There are various guides and videos online of how to do this.
 
Long time since I have done a conversion, but..... If your ammeter is reading on the correct side of the scale (i.e., counterclockwise), the car has been converted to negative ground. If you have had one large, continuous, boil over you probably have a maladjusted regulator. If the boil over was over time and gradually deposited acid around the battery box, that is a normal happening. Generally DC electrical devices do not care about current direction. Coils eventually do if you don't swap the primary leads. Light bulbs never care. Regulator should be on the vehicle right, at least if a left hand drive car. I think if your electric motors (heater fan, wipers, starter) are turning the right direction, polarity has been properly reversed.
Bob
 
Battery boiling over?! Yikes!!

Forget about the other issues until you solve this one. Either (1) there is something really wrong with the battery, or (2) your charging system is wildly overcharging the battery, or (3) you have a serious electrical short.

If you are not electrically knowledgeable, you will need to get someone else to sort it out. Having lots of jury-rigged wiring often means that something is screwed up royally, so it's probably not the best learning situation. I normally tell people to get a new wiring harness only as a last option, but in your case it might be easier just to rip it all out and start over. I've done that before.

Finally, get something benign and alkaline (washing soda is fine--I keep a big bag of Arm & Hammer around for that kind of use) and use it to wash out any area that was touched by the battery acid. Just flushing it out with water may not be enough.

Also, I'd keep the negative ground, if only for compatibility with future electrical things.
 
Without the right tools a mechanic is helpless. GO buy a good test lamp that also reads the voltages it is testing.This lets you know if a connection has corrosion (restance) . Buy a batch of new wire connectors and DIELECTRIC grease !! Always suspect a ground wire you have not personally
double checked. Unless your harness is fried, restore it circuit by circuit .I recommend power braid wiring covers to re-create the look
of the cloth covered wires .
Mad dog
 
Do you have a multimeter? If not, buy or borrow one and check battery voltage at rest and being charged. At rest, should be between 12.6 minimum and 13.6 or so. I don't know what charging voltage from a generator should be but alternator should put out about 14 volts or slightly more. My TR6 battery was installed backwards when I bought the car over 20 years ago and burned out the alternator. I replaced the alternator and not a wisp of trouble since. As others have pointed out, your battery appears to be seriously overcharged, probably due to the voltage regulator. I have no idea how to adjust it but others on here are more in the know. Your manuals may tell you as well or go online.
 
Wow. Ok guys, many thanks.

1st: it does have an aftermarket ammeter that reads positive amps when running.
2nd: Regulator is a new, sealed, non-adjustable type. Wiring is suspect, trying to confirm what goes where, but so far, it's ok.
3rd: I do have a multi-meter. I'll test the battery voltage at rest and running.
4th: The battery that boiled over later froze, failed and was replaced. Internal fault? The new one has had no trouble. Yet.
5th: I've found so many breaks in the insulation, bad/loose terminals, whonky connections, and lots of superfluous wires. Cleaning it up.

More info to follow.
Thanks again.
 
Battery boil over is one of 2 issues, neither related to system polarity. Either it is overfilled with water, or your voltage regulator is adjusted too high. Check the voltage with the engine running about 2,000 rpm. It should be running 13.7 to 14.4 volts. 13.7 is best if you run mostly on longer drives on a freeway. For short drives with a lot of stop and goes, 14.4 v works better. 14.4v or higher on long trips at high speed will boil the water out of your battery.

I would leave your polarity alone unless you have a reason to change it.
 
Good info, thanks. Had the generator tested yesterday at a reputable shop, it motors good and puts out good current. Unfortunately, the car I drove to the shop died, and required a tow to get it home. Looks like fuel pump. One darn thing after another......
 
We’ll, at least that’s mechanical!
 
I'm a mechanical guy too. At least that what my degree says. When it comes to electricity I don't understand why electricity doesn't pour out of the wall when you pull a plug out.
But, I've stayed with it for years and years and have developed a more friendly relationship with electrical stuff. Now, I'm good as long as I don't have to rebuild a flux capacitor. Luckily, they are available from O'Reilly's ...

So stay with it, get a Multimeter, and start learning.
 
I have a mechanical degree too, but I realized shortly into the degree that electrical controls go hand in hand with the mechanicals. I saw the future...to bad I didn't figure out a way to make money on the realization, though!?!
 
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