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laynrubber

Coles notes on 12 volt conversion please...

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I have been studying this conversion these past few weeks, reading other brand forums as well. I know the arguments to stay 6 volts and for the past few years I have had minimal problems but I am going ahead with this conversion. Not that I need to justify this but.....I tow a small Boler camper trailer using the Plymouth or my Mustang and changing my bulbs between 6 and 12 volts is tiresome, I needed a signal light flasher and a headlight once on a road trip.....‘‘twas unavailable in 6 volt. When camping I can’t charge my trailer 12 volt system with the car. We road trip a fair bit with the car and we can’t easily charge the blue tooth speaker or phones while travelling (I know there are electronic items to fix that).

 

Anyway....I want to convert to 12 volts but I haven’t found a good read on what works best when it comes to wiper motors and heater motors. Are they polarity sensitive ? Is the resistor method a cheap time limited path ? I think it would be best to find these motors in a 12 volt version but where do I find these ? I think I have a grasp on the lighting, fuel gauge and horn. I can then buy a 12 volt cooling fan to ditch my belt driven fan.

One wire alternator or the 3 wire alternator....any preference ?

Who has done this conversion and has pointers for me ?

Edited by laynrubber
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I don't know much on the heater motor except people saying you can use a 12 to 6 volt converter but they can get hot so I haven't did mine yet either many people say it is best to find a 12 volt motor for the heater.  When I went to 12 volts I went with the one wire alternator and it works great. My wiper motor is still vacuum run so I didn't have to change that. There is a site on the web that can change your old generator over to 12 volt if you want to keep the old look on the car but I didn't have the money to do that either. I do like the fact that the car starts much easier on the 12 volt verses 6 volts.

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O/k....yep I'm a hotrodder and my 1940 Dodge has a 318 Poly V8, etc, etc.............but I have the original speedo using a standard mopar speedo cable that fits both ends, the original oil gauge is mechanical and just screws into the block, the water temp gauge is mechanical and has a standard adaptor that allows the stock gauge to read the temp, the Amp gauge reads amps, doesn't care whether they are 6 or 12 volts and the Fuel gauge has a resistor on it for the past 45 yrs and its not absolutely accurate but I'm used to it......all the bulbs have been replaced with 12 volt equivalents, the headlights being 1940 are the 1st year for sealed beams so I have had H4 's again since 1973 or 4 .....and yep I rewired the car myself 40 yrs ago...... the heater is a 12 volt Smiths aftermarket heater tho' is rarely used, the wipers are BMC cable operated wipers that are 12 volt and it uses a 12 volt alternator.............I understand why people want to use 6volts but I'm not one of them..........the horn, electric fan and radio are all 12 volts also...........andyd

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I am in the process of changing my 39 Ply to 12 volt, at the point of gathering parts and will make the conversion in the spring.  Jegs sells a three speed 12 volt heater motor part # 70603 ($59.99) and switch 70604 ($19.99), fan shaft dimensions are the same and length & width slightly larger but still smaller than opening in heater .  My original fan motor wasn't the greatest, this seemed better than buying a voltage reducer.  Recently ordered, however haven't received yet,  hopefully will be able to test this weekend .  A local shop in Glassboro N.J. (Frank Todd) converted a spare  starter and generator to 12 volt.  The only visual difference is the generator is slightly longer and the voltage regulator will be different (same used on a 50s Plymouth).  Frank indicated if the starter isn't converted, run the risk of breaking front of starter due to sudden torque.  The generator won't put out as much as an alternator, but I want to keep the original look.

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I forgot to mention, for the fuel gauge I spoke with Instrument Services (800-558-2674).  They can convert my fuel gauge to 12 volt with the ohms that I want for $167.  May using a new sensor in the tank from ISSPRO (33 to 240 ohms).  Actually they find a new gauge and adapt the original face plate to it.  Haven't decided yet if I am going to do this or use a voltage reducer.  My tank sensor doesn't work so if I keep the original gauge will have to locate one with ohms to match.  Another option

Rich

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On my 38 Coupe, I use a 12 volt starter and generator from a 56 Dodge.   The heater is 6 volt, with a 12 to 6 ceramic type of reducer.    I ran my fuel gauge with the heater reducer also.

 

 

 

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On my 49, I used a 65a 1 wire alternator but if I had to do it again, I would use a 3 wire for better charging at idle but it's never been a problem.  I used a blower motor out of a 60's Dart and it was a bolt in and works good with the original 2 speed switch.  Instead of spending a lot of $$$ on converting the fuel gauge, I used a $12.00 runtz resistor from Speedway but it probably would work fine on 12v.  Been running my 6v starter as-is for years with no issues.  I converted my AMP gauge to a volt meter and the original clock has been running on 12v for years and works perfectly.  12v coil and a slant 6 electronic distributor because I have 12v makes a big difference starting.  I hide all my relays in the old voltage regulator on the firewall.

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I use the fan a lot in the summer to circulate air, for without rear windows the coupe gets  warm inside, even with the cowl vent.  Unfortunately the original fan motor burn out last summer, rather than replace with a 6 volt, opted to go with a 12 volt.  Jegs reduced the cost to $47 for a three speed motor, provided dimensions therefore I was confident it would fit before starting and I had a three speed switch.  I'm not familiar with other fan motors specification that would work.  Put the motor in this last weekend fit perfect.  Seven or eight years ago my original gas tank developed a leak, at that time no replacements were offered for the 39 Ply.  Not something you want to come home and find.  For safety, opted not to have it repaired and put a fuel cell in the trunk, as the car is kept in an attached garage.  Recently purchased a reproduction tank and will be taking the fuel cell out as it takes up space, however can use the sending unit from the fuel cell, which is 12 volt.  My original fuel gauge never worked that well, so rather than find a working fuel gauge and sending unit probably more practical for me to have the fuel gauge face put on a 12 v. GM gauge.  If the fuel gauge and sending unit were in good working order would of went with a reducer.  Went with the 12 volt generator to keep the stock look, not many accessories on the 39 to use electric, radio is about it.  My goal is to improve starting, headlights and able to get headlight bulbs easier.  

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This is not a real difficult conversion.

1) 12 volt genny and regulator or a 12 volt alt.

2) starter motor can handle the 12 volts or source a 1956 12 volt starter

3) all bulbs

4) 12 volt signal flasher

5) ballast resistor for coil or 12 volt coil keep spare ballasts in glove box

6) reverse polarity on amp gauge and/ or install an aftermarket volt gauge. 

7) heater motor use a beefy voltage reducer or better yet install a 12 volt motor its easy.

8  runtz voltage reducer for fuel gauge, early 2 wire types gas gauges  may compensate for the 12 volts.

9) radio you cannot voltage it without changing the vibrator to a negative polarity. Im sure there might be a dodad on the market for this purpose.

Wiper motors will need a voltage reduction but yours are prolly vacuum.

Thats basically about it.

Goid luck I love my 12 volts on.my 55 Fargo.

 

 

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Thanks all for the information. The wipers on this car are electric so this is something I need to convert as well. I am not wanting to use resistors for the fan and wiper motors. The fuel gauge though yes I will resist that one. Ammeter, lights, flasher....all easy enough. The alternator though Adam mentioned he would not use a single wire again....I have heard that from a couple others. I think I will use a 3 wire with an external regulator. As for my coil....I don't have a ballast resistor on it now, and I plan to use a spare coil from my vintage Mustang spares. No resistor used on my 68 Mustang. Condensor I will change up. 

Question about reversing to a negative ground system......are the heater motor and wiper motor polarity sensitive ? Will they need to be reversed ?

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16 minutes ago, laynrubber said:

Thanks all for the information. The wipers on this car are electric so this is something I need to convert as well. I am not wanting to use resistors for the fan and wiper motors. The fuel gauge though yes I will resist that one. Ammeter, lights, flasher....all easy enough. The alternator though Adam mentioned he would not use a single wire again....I have heard that from a couple others. I think I will use a 3 wire with an external regulator. As for my coil....I don't have a ballast resistor on it now, and I plan to use a spare coil from my vintage Mustang spares. No resistor used on my 68 Mustang. Condensor I will change up. 

Question about reversing to a negative ground system......are the heater motor and wiper motor polarity sensitive ? Will they need to be reversed ?

No they are not polarity sensitive. Only thd radio 

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Had my radio converted to 12 volt by "Old Car Radio", Charles Fogery, Harrison, TN.  423-344-8357.  Works great, he added FM, leads for extra speakers and a jack for a Scandisk which I can easily transfer songs from the computer to.  Through the Scandisk also have access to blue tooth for wireless speakers.   What I am doing won't work for everyone, but it works for me.

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I have started to do this conversion, removing all items and making a list of what comes out, with new part numbers of what goes back in. Won’t go into too many details yet until the conversion is done and smoke tested 😁.

So far though I am $140 into it, this bought a non resistored coil, 12 volt regulator and connector, and an alternator. All of which I am sourcing from Napa and calling them all 1968 Mustang parts so far. Needing a different pulley for the alt. Have a list now for the light bulbs and flasher. My Napa guy says bring the heater motor in an we can match something.

Further updates as I progress......

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If you are keeping the points, measure the resistance across the + and - posts of the coil and make sure your total primary resistance is correct.  I believe it should be 3K ohms total in the primary circuit.  So if your coil has 1.5k ohms primary resistance built into it, you need to add a 1.5k ohm resistor to the power wire to the coil.  In all it should add up to 3k ohms or point life will suffer.

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I'm in the middle of 12 volt conversion on my 40 P9 and am stuck at the fuel gage wiring. I have installed the 12 to 6 volt runtz, from 5th Ave Garage, on the IGN SW terminal and ran the ignition feed wire to it but now at a loss as to how to wire from gage Points 1&2 to sending unit(Both original). My  kit only has 2 wires for Fuel Gage. 1 to the gage and the other to the sender. I could use some help here. Thanks in advance. My gage is exactly like the picture attatched.

post-7346-0-30459200-1456930685.jpg

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