New to the Forum: Converting 6V to 12V

[1949Chrysler]

I am new to the Forum and new to Cadillacs, this Forum page looks to be a great resource for me.   I am helping a friend of mine complete his 1938 Cadillac Opera Coupe.    Car was being restored by an expert, yet this came to a stop after the sad passing of this expert.   I have stepped in to help complete the restoration and get this great car back on the road.

Here is my major challenge at the moment:
Car was in the process of being converted over to 12V from 6V.   This was about 75% completed, wiring harness was not completely hooked up.   
With this switch over to 12V what do I need to do to protect the instruments.  Heavy duty resistors?
What should I install for the Headlight bulbs?  32 Candle Power 12V Bulbs?  Halogen bulbs?
What 12v Coil should now be used?   (Part Number?)
Should the points and condenser be changed because of the voltage change?  ( Part numbers?)   
As I understand it the voltage regulator has been converted and the generator as well.

Any advice would help as I sort out this conversion and this great car.

Regards,    Brian S.

[Steve Passmore]

These are rare cars. I owned one that I only recently sold.

Your biggest hurdle will be people here disagreeing with the conversation .  But that aside, your biggest job is already done with the generator and regulator. 
A standard 12 volt coil will work but there is no 12 volt coil I know off that will duplicate the original for look because the originals were connected to the ignition switch through an armored cable and a cap on the base of the coil.
A dynamo might struggle to keep Halogen bulbs going and much will depend on whether you keep the original reflectors as the bulbs required were unique to these early models.  If you change the reflectors you loose the ability to adjust the beam.
Nothing in the distributor needs to change.  If you are also changing to negative earth the wires on your ammeter need to be swapped.
And a precaution I fit a small resistor to the supply wire on the fuel gauge.
Any heater you fit would need a much bigger voltage reducer or a 12 volt motor.
Starter motor in good condition will last many years as long as car starts easily and quickly.  Horns will continue to work but good and loud.

[Cadillac Jack 82]

Yup I'd be one of those but to each their own.  I had a 1941 Ford (far thing from a rare Caddy) that was 6 volt and it worked like a champ.  the lights weren't as bright as modern lights so I typically just left my high beams on.

[Bob Schuman]

Brian,
When I did a similar job on my 41 many years ago I used a 40 ohm 5 watt resistor in series with the power feed to the gas gauge dash unit, so the gauge saw about 7 volts, and it worked perfectly. Your temperature gauge is not electrical, so nothing needs changing there.
Bob Schuman

[bcroe]

Going to a 12V system, be sure the 12V coil has the right ballast resistor wired
in series.  Otherwise expect soon burned out points.  Bruce Roe

[1949Chrysler]

Since I am working on this car to help out a friend, the stories of what has been done is a bit sketchy.......I decided to validate.   Took the generator off the car and down to the local Generator and Starter shop.  They hooked it up and spun it.............its putting out 6V not 12V as I was told by the owner of the car.   I suppose it was slated for the conversion but never done.   Sooooo glad I decided to "suspect" the story.  Hence I am keeping this car as 6V!!!!!!   
So I have just purchased a new 6v coil, switching the bulbs back to 6V and keeping this car the way it was designed.

I need to go and purchase a 6V Battery.   Any recommendations???   Lead Acid?  Gel?

Brian

[Bill Ingler #7799]

Brian: I have used a 6 volt Optima battery on several of my cars with good results. Good cranking amps and I get from 5-7 years on a battery. Since it is a gel battery the one caution is use a very low amp charger such as a Battery  Tender Model 021-0127 which a low output charger/tender. Using some of the 6 volt chargers with high output can fry a gel battery if not removed when battery is fully charged. Also make sure you have at least 00 gage battery cables and also a good idea with any old car is to install a battery cut off switch.   Bill

[tturley]

I left my Lasalle stock except I installed an eight volt battery and adjusted regulator to put out nine volts at the battery so it would charge. Starts great now bang lights are a little brighter.

Did not change anything else and it was an easy upgrade.
Some people have said they have issues with burning out bulbs but I have not and think maybe they have regulator set to high.

Downside is I have never found a eight volt charger but did install an eight gold tender.

My battery is under floorboard so authenticity is not an issue.

[Steve Passmore]

Is that classed as a Golf cart battery Tom?

[tturley]

Electric golf cars used 6v batteries in the past but have used 8v for quite some time now.
They are side terminal batteries though.
I bought mine from a tractor supply company, I don't know if some tractors are built 8v or farmers convert from 6v.
They are top mount and are very close to the same size as a 6v