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Hi all,

I have a'41 110 Club Coupe with original wiring that is starting to crumble. I'd like to replace it with a new wiring harness and thought that while I was in there would change the car to 12 Volt and install an electronic ignition.

Can anyone lend some insight into what I should consider when making these changes? In particular:

1. What is the best wiring harness to use? (Painless Wiring? EZ-Wiring?)
2. What parts need to be changed when going from 6V to 12V and where would I find a list of the correct new part numbers, specifically alternator that would fit, voltage regulator, coil, ignition key, etc.
3. I know the instruments need to be stepped down to 6Volts...what resistors do I use? Where do I find them and where exactly in line do they go?
4. Finally, is it possible to change the headlights to 12Volt and not have to step them down? The lights on it now are so dim they are practically useless at night.

Any other considerations that I have overlooked?

Thank you all in advance!!

I cannot add too much to your topic but recommend you go with the 6v gauge wires in case you or a future owner prefer to go back to 6v. The price difference should not be much. Also there are vendors who can supply the correct fabric covered wires if you find that to be important.

Ragtime - I bought my wiring for my 39 120 from Potomac Packards, and it is dead on accurate. Costs a bit more, but fairly easy to follow. I agree that you should use the 6 volt wiring as it is heavier, and if someone in the future wants to change it back, that would be a good selling point. My 39 120 was converted to 12v and I changed it back to 6v. With the new wiring and some double ought cables on the battery, the six volt bulbs are just as bright as the 12 volt ones on my 65 TBird.

You can get resisters from Chev's of the 40's, Mac's Fords for Tbirds or Model A's. You will need resisters for the voltage gauge, horn, clock and gas gauge I think. Ditto radio if you have one. You will need to change all of the light bulbs to 12 volts. Mac's has 6 and 12 volt alternators in both negative and positive ground. If you decide to go to 12 volt, which I think is unnecessary unless you don't like hunting for 6 volt bulbs, I have a 12 volt starter for sale. I'll post it in the "for sale" section.

I don't think you will find a standard list of part numbers or even what items to replace all listed in one place. Each conversion is different. Fifth Avenue Garage has a printed general guideline but it is not Packard specific. They also carry some resistors but others do too. 12v bulbs you can get at parts stores -- just take an old one to compare and make sure the base is the same as the old 6v version. For many of them you could download a 55-6 owners manual from the site and use the bulb chart to get a starting number to ask for to compare. Headlights just plug in so again, no problem finding new bulbs.

Some other items may have 12v replacements but others not. For example, some Packard heaters have a motor shape or circuit that will not adapt easily to todays motors so you will need a resistor. If you have an original R9 OD there are no 12v solenoids and the relay box -- even in 6v -- is almost extinct. To keep the OD operational you will have to supply a healthy 20 amp 6volts to the complete unit. Resistors are not a good idea on ODs because the current draw is so different depending on what is happening. If you are trying to keep an authentic look, doubt you will find an original looking horn in 12v either so another large resistor for the high current they need. Alternators, you are on your own. You will have to adapt and if your engine uses the 1" wide belt there is only one place I've heard that might be able to supply an alternator with the proper size wide pulley.

You might consider a dual voltage setup. Convert to 12v for the engine, lights, etc and wire accordingly but buy one of the 12 to 6v converters to run all the original accessories -- particularly the OD -- that have no easy replacement. There are some on ebay made specifically for the car conversion purpose and might even be cheaper than buying individual resistors. Gauges could go either way -- either off the 6v converter supply or get a Runtz reducer or resistor for the gas and oil gauge. IIRC, the temp is mechanical and ammeter won't care about the voltage but with the increased amp output from an alternator may have to be shunted or even bypassed.

For the most part, since you are going with a new loom it would be fairly easy to keep a few things separate. The Painless is an option several have used but if looks are important, the plastic wire in a 41 would be a dead giveaway. There are some companies like EZ2Wire that advertise "heavy duty" universal looms. Those generally have a larger wire size suitable for 6v in them.

Thank you all for your quick replies and input! I am now, however, thoroughly confused!

My intent for switching to 12 Volts was a sense that it was just "better" (If not, why then did all cars switch to it?). It seems the consensus here is to just keep it 6V.

What exactly are the pros and cons of 6V vs 12V and what would be a good reason for converting? My car is very weak to crank over (even with brand new 6V battery) and can take up to 5 minutes to cold start. I thought with 12V, it would crank over quicker and also be able to be jump started from another modern car if necessary.

I have had the transmission completely rebuilt with all NOS parts, the brake system has all been renewed and the steering box is freshly rebuilt. Taking a look at the crumbly old wiring, my thought was that was the next area to tackle in order to end up with a very reliable and trusty car. The three things I identified doing in that area were: 1) New wire loom 2) 12 Volt conversion, and 3) Electronic ignition.

The first point should prevent me from burning to the ground, so probably a good investment of time and money! But it sounds like point number 2 won't have any real benefit?

Finally, what do you guys think about installing electronic ignition? I am not a stickler for under-the-hood period accuracy but just want a solid, reliable car that my wife can drive every day without worrying about whether it will start (or catch fire!).

What do you think?

Thanks again and I am grateful for the good folks on this forum willing to help a newcomer to this wonderful pasttime.

My opinion is there is no benefit to switch to 12v. A slow cranking starter may need to be rebuilt or there could be some other issue. Converting to 12v may get the starter to spin faster, but that would just mask an underlying issue. My car cranked fine on 6v as they did when they were new.

Ragtime, the reason manufacturers switched to 12-volt in the 1950s was the load imposed by new electrical demands from air conditioning, power windows and seats, and the like. With just the items that were typically on a car in 1941, 12-volt is completely unneeded and offers no advantages. And you can still jump a 6-volt car from 12-volts - just make sure all the lights are off (or you'll burn out the bulbs) and keep the jumpers on for only as long as required and in no case longer than perhaps 20 seconds at a time.

If your car takes 5 minutes to get started, you've one or more other problems to address - it should start in a couple of turns, cold or hot. Make sure the cables are true 6-volt cables "0" gauge at the least. Connections bright and clean. Starter motor checked for bushings/bearings, brushes, commutator, etc. And of course fuel and ignition in good order.

Twelve volt systems allow the manufacture to use smaller gauge wire, which represents a cost savings. Also, as already mentioned 12 v provides more power for cranking.

If your car turns over slow the suggestion, as mentioned, rebuilding the starter is a good suggestion. My '51 was a bear to start after it sat for a week or two and required a squirt of starting fluid. I traced the cause to lack of gas in the carburetor. The problem went a away when the electric fuel pump failed and was replaced. The new pump provided more gas when the key was turned on. Not sure where the gas in the carb. went when the car sat for awhile - maybe an indicator that the carb. needs to be rebuilt.

By the way the '51 came with an electric pump when I bought it. I may pull the mechanical one when I get the time and rebuild it and return the car to a more original look. However, the '32 that I'm restoring occupies most of my garage time.

I think that changing out the old wiring and getting nice fresh, clean grounds will go a long way to solving your starting and lighting problems. It sure cured the ones on my 39 120. Next will be rewiring of the 51! Should have done it when the engine was out a few years ago, but I ran out of play money.