Packard Forum Index » Post-War (1946-54)

I asked before, but got not quite ALL the answers I think:

When I convert from 6 volt positive ground with generator to 12 volt negative ground with alternator on my 1952 200 Deluxe, I know:

- Obviously all bulbs need to go to 12 volt

- Need a 12 volt coil, and a ballast resistor, and hook the coil up with the negative side connected to the distributor

- Distributor itself is untouched

- I need to use a Runtz resistor to protect each instrument guage (fuel, temperature, clock)and the radio

- I can apply 12 volts to the 6 volt starter and it will live, but probably have a shorter life as a result

- 12 volt horn relay (is this really necessary for rare and short duration use?)

- I can apply 12 volts to the 6 volt horns, and they will live for at least a while, and then I can replace them :)

- The voltage reguator goes away along with the generator, since I have the alternator


But, what about:

- The starter motor solenoid

- The Borg Warner OD relay

- The Borg Warner OD solenoid

- Does the change in both voltage and polarity necessitate any changes to the "battery" light circuit?

- Does the change in both voltage and pol;arity necessitate any changes to the "oil pressure" light circuit?

- For safety, swap out the 6 volt cigar lighter to a 12 volt (so a guest or child does not accdientally start a fire when I am not looking)

- Anything else I haven't thought of?

I really don't want to convert, BUT:

1. My wiring needs replacmeent anyway (old & brittle)

2. A generator and voltage regulator that needs adjustment from time to time seem like a rather unreliable setup for long term torublefree motoring

3. I MUST add air conditioning - we get 100 degree highs all summer - well over 45 days over 100 so far this season, and this is my daily driver

Jim G

The starter solenoid and OD stuff will also have to change. The bat and oil lights are not polarity dependent. Don't think you'll need any resistor for gauges. They operate off a voltage regulator and according to parts manual, the same regulator is used in 55-6 but the clock & radio would need a resistor. The turn signal flasher needs to change. Horn relays are cheap so would do it.

Howard hit on everything I was going to add. For my Cig lighter, I just replaced the 6v element (the coil piece at the end of the "knob"), with one from a 55/56. So it keeps the correct "knob".

Also you will need a high amp voltage step-down for the blower fan, or use the 12v motor from a 55/56. The blower housing is different, but the motor and squirrel cage are the same.

I just read the extensive list of things that need to be replaced to convert to a 12 volt system. I don't mean to offend anyone but I just don't get the the big push to convert. Why spend all that money and effort when what you have will work just fine? I drive a 6 volt pos ground Packard every day with out any problem. The lights light, the starter starts, the charger charges and the pistons, well they work too. Why fix something that isn't broken? There is nothing bad or wrong with 6 volt systems. They work perfectly well. Am I missing something here?

The need for A/C is the biggest reason for going 12v. A/C was not available from Packard during 1952, and there are very little options for 6v A/C.

The '54 6v A/C systems are as rare as hens teeth.

Hi Kev, That makes a lot of since. Was not thinking about A/C. Seems the 12 volt A/C clutch would be the big problem. Fan motors can be substituted easily enough. There must be a way to create the 12 volts necessary for the clutch and still keep the rest of the car on 6 volts.

Bob1951: You reaction is typical and understandable, but that's exactly why I reiterated my reasons for the conversion near the end of my posting.

Getting that AC clutch activated is one of the 2 big deals.

The other is the darn generator / regulator setup:

1. I have seen in writing from experienced mechanics that this electro-mechanical setup with its voodoo "regulator adjustments" needed from time to time is the cause of the vast majority of unreliability issues with old cars. I can believe it. Have you read the section in the service manual on regulator adjustments? It's a joke. I'm absolutely certain that any Packard engineer alive today would have made the swap to an alternator in his personal Packard!

2. Even when working, there is no way a 45 amp generator is going to be sufficient for a car with real HVAC. Every time the AC kicks on, the headlights would dim, and you'd need to remember to turn the AC switch off before cranking the starter (to prevent the AC from trying to engage during cranking)! And, since the generator cut-in speed on my Packard is 920 rpm, and the car idles at 400 rpm, whenever you are idling, you are discharging the battery. If the AC is engaging and disengaging, and the blower is running and the lights are one, you are pulling power like crazy out of the battery. I don't need that aggravation!

Jim G

BigKev: The cigar lighter solution is a great idea.

For the HVAC, I plan to use an "Old Air" brand (Fort Worth, Texas)underdash setup whose panel shape is an almost perfect match for the instrument panel shape in my Packard. This modern retrofit system is of course 12 volt, and will make it unnecessary to butch the backide of my dash or to eliminate my glove compartment drawer.

Jim G

I just checked the "Fifth Avenue Internet Garage", where Randy Rundle hangs out. Good news and bad on the 12 volt conversion of the Borg Warner OD system:

- The 6 volt relay, and thre kickdown switch, both work just fine with 12 volts

- The 6 volt SOLENOID however (this is the part attached to the actual overdrive)must be changed to a 12 volt. Two problems:

1. The cost is $265 plus shipping. The $265 cost makes Randy's 6-volt alternator, with output of 60 amps, 7.5 volts and featuring a solid state internal regulator and "DA" plug, very attractive to those wanting alternator reliability and output, who do not need air conditoning. Part # is 89502S - $205.00 each.


2. There were 2 "shaft lengths" used (measured from the mounting lfange to the tip of the metal shaft)on these solenoids. Randy ONLY has the one that is 1.25" in that dimension. This covers MOST cars that used the BW overdrive, but early 1950s Packards MIGHT be an exception. Does anyone know the length of the shaft on a 1952 Packard 200 with Borg Warner overdrive?

Jim G

There have been a few with burned out or otherwise damaged OD relays for unknown reasons.
While changing to yours to original 12V relay might be expensive, one poster came up with a very viable option of using a headlight relay. In that case it was using a VW relay to replace a 6V OD, but see no reason why you couldn't go the other way and use a 12V relay to work as well. Just be sure the contacts can carry the amps. Check out 49Packard thread on his overdrive problems.