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Jim,

Two views of ground cable routing. Goes to top bolt of water pump I believe. (Haven't looked at the Derham in a while). If you need more info I can go over on Wens afternoon for you.

Out of focus line on left side of second image is battery tray so you have relation of area.

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Those two pictures should do the job.

I will take a peek under my hood and see if that works.

My car has add-on-A/C which means a longer fan belt and there is an additional pully up around the top of the water pump that may be in the way.

It may have to land on the front bolt of the oil filter to stay out of the way of things.

Thanks for doing the research.

My car was restored before I bought it and my before, under the hood looks about like yours so now I know I didn't pay much for the ole girl when I see the work they did.

Jim

If you don't care about the correct placement and just want a good, convenient location for the ground, try the location used by Packard for quite a few postwar years up thru 1950 I believe, to one of the bolts that hold the generator bracket to the engine block.

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I'm kind of shocked (pun intended) that a battery could be hooked up backwards polarity from what it should be and the starter would run the right direction.

I guess I don't really need to know why this is possible, but some, like me, may wonder now whether their battery was simply hooked up incorrectly and ought to be reversed, or whether it went through the sacred ritual of "re-polarizing the generator" and whatever is done. Are the connections on the voltage regulator also necessarily reversed?

I have only a generator light, and it goes out just fine when the car is started, but the battery is hooked up reversed (negative ground).

Is there a quick way to test whether it was intentionally, and correctly, reversed?

I changed the polarity on my 55 Clipper (12-volts) to negative ground. I had to polarize the regulator/generator and change the leads on the coil. Everything continues to work normally. My radio does not work because it needs a new vibrator, but it was this way before the change. The clock is unaffected. I changed polarity so that I could use modern accessories (e.g., GPS, iPod, etc.). I still need to change out the cigar lighter for a modern one or install a modern one as a dedicated power outlet which is probably the better choice.

(o{}o)

I believe a brush type motor that doesn't use permanent magnets will turn the proper direction regardless of the battery polarity. Don't ask me why. All the fan motors, antenna, and starter should work regardless. Ignition won't care.

I studied the radio schematic (I work in television engineering) and I didn't see anything in the power supply that was polarity sensitive (1954 car), no polarized capacitors on the 6 volt side. There is some circuitry in the wonder bar tuning system that may not work.

The later 6 volt radios used a four pin vibrator and they don't care about polarity. The older car radios used a synchronous vibrator which decided the DC polarity of the B+ voltage. I recall some radios you could rotate the vibrator in its socket to decided the polarity

I actually could see nothing in the generator - Regulator that would care but you do have to polarize the generator which takes about two seconds.

Both the Delco and Autolite service information talks about using the proper polarity regulator claiming early failure is the wrong one is used. There is something in the composition of the voltage relay contacts that determines which way it works best. As that set of contacts is vibrating open / closed continuously when the engine is running I can see a need to reduce arcing. Regulators are stamped on the frame NEG of POS quite often which refers to ground. Many of the after-market regulators may have just a number and you have to consult the cross reference manual to find out what it will fit.

Be aware that these larger, late 6 volt cars have a generator rated at 45 Amps which is probably getting close to the load you have with the heater fans, radio, headlights all turned on and you just cranked the engine.


Jim

I can answer for polarity and electric motors on 12 volt applications as the polarity was changed over on my '55 before I got it. I found this out when I hooked up the battery to Positive Ground and found that my Amp gauge worked "backwards". Switched the cables around on the battery and everything was fine. Including the power window motors. They, at least don't care which post is ground and neither does the clock. Although it seems to me it should too. I'm just grateful that it doesn't.

Actually, the ground is switched on my '51 as well and the clock works fine as does the radio and heater blower.

Think of the motor being wired so it always has a magnet having a north and south pole fixed in a certain way -- one in the field coil and one in the armature. The armature will try to pull toward the field or push away depending on how it is wired. Changing the polarity feeding the entire motor won't matter because while the north and south poles might swap and now be on different parts the pieces will still be in the same relationship -- either pulling toward each other or repelling each other so it still runs the same direction. A permanent magnet motor always has the field one way which can't change so reversing polarity to that motor will change direction because one part changes relationship.

What does re-polarizing the generator involved in the "two minutes" that it is said that it takes. (Lots of things that can be done in less than two minutes, or even two seconds, can be done wrong.)

On this same note, why is it that polarity makes a difference to the generator if it doesn't matter to the starter?

Other puzzlers:

A voltage regulator marked "Positive" on a car that has the battery hooked up with negative ground doesn't rule out that the generator was re-polarized and everything else set up to run negative ground--just that a shoddy half @ssed job was done... and how can you tell if the generator HAS been re-polarized?

Earlier, it was mentioned that, even if the starter cranks and everything "works" the spark may be compromised and firing backwards at the plug. Doesn't sound like a good idea how can it be verified that it's not happening. I believe this was the result of the coil being hooked up with the "wrong" polarity, and how is it determined if the coil is hooked up "right" not knowing if all other things are equal?

In other words, as always, everything is connected to everything else so everything needs to be checked to make sure the whole is connected correctly.

So how do you troubleshoot the ignition and charging system to verify that it has been set up correctly in its entirety for either negative or positive ground? It's been a long discussion, but there still isn't a clear answer on this.

Hopefully someone else will have a bit more detail for your questions but here's a quick response.

Polarizing a generator only requires an instantaneous connection. Longer than that accomplishes nothing. Polarizing the generator simply instills a small amount of permanent magnetism of the proper orientation in the field assemblies.

The polarity of the coil should be such that the coil terminal that goes to the distributor is the same as the battery ground. There was an old-time test using the carbon point in a pencil to check the plug polarity but I don't recall the details - perhaps some one else will.

If a generator should have been polarized and wasn't it won't show a charge. If it shows a charge then the polariztion is correct.

I've been told but can't confirm that using a regulator intended for negative ground on a positive ground car gives shorter life because the alloy of the contact points is different and particular to the system ground to minimize alloy transfer between the points. Whether this is true or not or if there is more to it I don't know but our resident expert on this is probably Jason from AER so perhaps he'll comment.