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I recently purchased a 1949 Club Sedan with the 288. I noticed that the battery was negative grounded and after reading what I found posted here I decided to reverse it. I pulled and rotated the battery and reconnected it and it started immediately, and the ammeter seemed to be reading correctly. I next took a jumper and gave a quick touch to the BAT terminal on the regulator and the ARM terminal, got a spark and instantly removed it. Unfortunately I forgot and did this while the motor was running. The engine stopped and now I can't get it restarted. Did I damage the regulator? Another possible problem is that this one has an electric fuel pump - will it work with positive ground? When I turn the key I hear it start to humm, but perhaps it is going in reverse?

Can anyone suggest what I might try now? Thank you.

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Nice looking car and welcome to the forum.

Most electric fuel pumps do not like reverse polarity so that is the first place to check. If you have a glass fuel filter you can see if there is anything happening. If you are lucky the pump is the type with two separate wires marked pos and neg and you can reverse the wires making the positive lead go to the frame now. Hopefully the pump was not damaged but most pulse types are solid state so it is a good possibility it was. If there is only one wire then either the pump is polarity specific with a different pump for whichever ground the car has or polarity does not matter.

As to the polarizing with engine on, it is hard to say if any damage was done. The cutout points in the reg. between those two terminals should have been closed and in theory no damage would have occurred but the regulator could be polarity specific too. You do need to verify when the engine and key is off the cutout points open to disconnect the generator from the battery. If the generator feels very hot in relation to the rest of the engine chances are the points are stuck and it is getting voltage instead of being disconnected.

If the car was purposely converted to negative ground there are a couple of other things that might need checking. One would be the coil as it is more efficient if wired according to the cars polarity. If car is now pos ground the + side of the coil should go to the dist. Also the ammeter wires may have been reversed when the conversion was done and instead of the charging indication you got before, it was really not charging. You can verify that with everything off by turning on the headlights. If ammeter reads charge, the wires were reversed and need to reverse back. If the radio vibrator was replaced with a modern solid state replacement those are definitely polarity specific.

G'day Wolfstalker,
to PackardInfo.

As Howard said, nice looking '49 Club Sedan which I invite you to include in the Packard Owner's Registry.

Thanks for the speedy reply. I saw two wires on the fuel pump so I'll try and reverse those and see if that brings any joy. Otherwise, I suppose I'll need a new one - any suggestions on a brand or model number?

Same for the regulator - mine has one mounting screw at the top ear and three screw terminals in a row along the bottom ARM -FLD - BAT. Anyone know what make and model that is?

When I changed the polarity and then started the car it fired instantly, but just after I did the erroneous polarity touch at the reg it stopped running and will not restart, which leads me to believe that the reg is probably OK but the modern elec fuel pump may have been harmed.

That's what I get for not reading all the way through and seeing on a later post that the polarity things should be done with the engine off. Oh well...

Wolfstalker for the very quick inclusion of your '49 Deluxe Eight Club Sedan in the Registry!

If it turns out you need a new pump, several have used Airtex pumps which are available from local parts stores or Amazon. Just about any quality electric pump will work as long as the pressure output is not too high. Believe the pressure spec out of the stock mechanical pump for your car is 4 to 4 1/2 psi.

Airtex has three 6v pumps in that range. Packard used 5/16 lines so two would fit with the least problem. If you are relying strictly on the electric pump and just a modern filter I would choose the E8902 rated at 2 1/2-4psi. If the electric is pushing fuel thru the mechanical pump and its built in screen type filter plus an optional ceramic filter at the carb then you can most likely handle the E8011 at 5-8 psi. Both will allow the mechanical pump to pull fuel thru with the pump turned off.

The E84259 rotary pump will require a bit of fitting adaption and if you have the mechanical pump in line, most rotary pumps will not allow fuel to pass unless they are running. It is also a bit higher capacity than what is needed but most rotary types are much quieter than the pulse types.

Was thinking about why the car would not start again. It could be electrical and depending on how the pump was wired, conceivably the pump was damaged and if it was wired to the same terminal the coil is fed from the voltage to the coil could be pulled down by the damaged pump to the point there is not enough spark.

I pulled the regulator and took it to a guy that had an old Sun Machine rigged up in his garage for testing, he checked it and said it was OK, so I reinstalled, but still wouldn't start. So I switched the two wires on the fuel pump and that did it - runs now like a Packard should on positive ground.

Now if I can just keep people from playing with the switches and leaving the courtesy lights or something else on and running down the battery.

Thanks for all the help and suggestions...

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Good to hear. I take it the pump was not damaged -- at least not that you can see at the moment. I have no idea how well those things are protected from accidental reverse polarity. It could have been well protected and there was no damage but the fact it was pulling down the coil voltage means some current was getting thru. If it is your only source of fuel supply I would be careful and keep a watchful eye or be prepared for sudden failure. Most solid state devices are unforgiving and once the deed is done can fail without warning.

I am curious about the ammeter. Some have had to reverse the wiring to theirs when the polarity was changed. Did you have to do anything to yours and have you confirmed the ammeter is reading correctly and generator is charging properly.

Hi all, I've been reading this post with some interest and curious about switching the polarity.

I would think that switching the polarity from the standard positive ground to a non-standard negative ground system would cause trouble with the relay systems such as overdrive and any other solenoid like in the starter. The coil would not be as efficient but I bet there would be more issues than that.

Can one simply switch the battery terminals around, repolarize the generator, and have the car run correctly?

I would think the starter would run backwards would it not?

ALSO... I am installing a new generator so can somebody walk me through the process to polarize the generator?

Thanks again!

Bill

Ordinary solenoids and relays of our vintage don't really care about the polarity. The voltage just makes them an electromagnet to attract a piece of metal so it generally doesn't matter whether a north or south pole of a magnet does the attracting. Modern units are sometimes equipped with internal diodes or other back emf suppression means across the coil and those would care.

The ign coils themselves also do not care but the loss of efficiency comes in to play at the spark plug. The spark is much more efficient when it jumps from the hot center electrode to the cooler side wire because the electrode heat causes electrons to be in a state where less energy is required to "break them free". If the coil polarity is reversed the spark will still jump the gap but has to jump the other direction starting at a colder electrode so has to work harder. If another part of the electrical system is marginal that tiny bit more effort required may be enough to cause the spark to be weak or in worst cases not be able to jump the gap at all.

Regular stock Packard motors do not care about polarity since the relationship between the field and the armature is hard wired inside the motor. For example, a north pole on the field will attract an opposite south pole a few degrees away on the armature and will spin the shaft. If you change the polarity of the input to the motor, while the north and south poles internally will change they are still hard wired together in the same rotational relationship and will both change at the same time so opposites will still attract. Where motor issues arise is on motors where the field and armature are wired separately and one changes but the other does not. Those motors will run backwards as will permanent magnet motors where the field never changes. In those, the armature only can reverse polarity depending on input so it will run either direction. Modern power window motors take advantage of that whereas our era motors used either separate forward and reverse wound field windings or else a separate field winding with a reversing relay to change the relationship.

To polarize the generator have the engine and key off then use a decent size wire to momentarily connect -- 1 or 2 seconds -- between the BAT terminal and the ARM or GEN terminal of the regulator.

The momentary voltage applied back to the generator turns the field and armature into an electromagnet and results in a tiny residual magnetic field of the proper polarity being "stored" on the generator pole shoes. Because the generator and field coils are disconnected when the generator is still the generator uses that tiny residual magnetic field to produce a small low current voltage of the correct polarity when it first starts turning. Once there is some voltage out it can energize the cut out contacts in the regulator which connects the generator to the battery. When it is connected the regulator then can feed battery voltage to strengthen the field so the generator can produce to the capacity required.