Hey guys looking for a little help.
I've recently purchased a 51 F1 and I am looking to convert the 6 volt system to 12. It is all stock under the hood (239 flathead) and I am tired of the sluggish starting and dim lights. I've been looking around the net to see if there is a kit with all items needed to do the conversion, but I am having no luck (found chevy kits all over the place). Guess what I am looking for is a link if any knows of a site or if anyone knows everything that will be needed to change over the system, I'm guessing the simple stuff like generator over to an alt, gauge cluster (or adding a resistor to drop the voltage back to 6), coil, lamps/bulbs, etc. I've read the starter does not need to be changed will work fine on the 12v system.

-Thanks for the help
Willie

 

Welcome to FTE, Willie. Glad to have you on board. This is a question that comes up about once a week and rather than reinvent the wheel, go to "Julie's Cool 51" gallery. Julie has put together some great schematics for just about everything electrical on these old trucks. She is more or less the electrical guru on the site. If you can't find what you are looking for, send her an e-mail and I'm sure she can help you out. Jump right in and join the group. You will have to have 25 post before all of the options on the site will work for you. Also look at the top of page one on the forum at the FAQ. Lots of good information there for you. Again, welcome, looking forward to following your project.

Gil

 

Hi Willis Welcome to FTE

Julu Gurie here! tee hee!

Yep this comes up once a week about so we have lots of background and threads for the conversion.

It really is a very simple process if you do some moderate preplanning, familiarize yourself with your truck, know what youwant to support electrically, and just connect one wire at a time - that's all!

As mentioned, I have a gallery with some Power Point drawings of switches, and signal flow for the three electrical subsystems you will want to group - engine, lights, and accessories. Take a look at those and when you know what kind of set up you would like, write me an e-mail (include your real e-mail address) and I will send you the ones that are applicable and even modify them for your needs. That way youcan enlarge or modify them for your needs. They are pretty straight forward.

I have saved links for wiring and problem solving on just about everything you could imagine.

So just to start, here are a few things to think about:

1) Do you want a prefabricated/manufactured wiring harness, or do you want to wire one strand at a time yourself. I prefer to wire one strand at a time. That elliminates getting cross wired or depending on vendors to buld the harness to fit your needs. But the "EZ wiring harness" is very highly thought of here as well.

2) I would definately recommend you go with a one wire type altrnator - either GM or after market. This elliminates the external voltage regulator and is a much cleaner and dependable set up. An alternator rated at 75 amps will be more than sufficient. I have links for that installation as well.

3) Decide what extra electrical items you would like on the truck (ie spotlights, stereo, electric fuel pump, electric fans, etc)

4) Here are the items that MUST be REPLACED for the conversion: Generator/regulator; light bulbs; power distribution point (in the 51 it's two circuit breakers so you will have to bypass those and use fuse blocks); points, condenser, coil; radio; cigarette lighter; battery; Starter solenoid; and headlight switch. The current headlight switch will work ok except for the dimmer on the instriment panel/speedometer lights. I you want to keep the stock switch, that's ok, you just can't dim the instrument lights.

These items will work if you install voltage reducers or adapters such as the little reducers for the gauges or vol-ta-drop voltage reducers for the accessories: Gauges; heater, wipers. I have pictures and installation threads for all of these.

The starter need not be changed, but you have to be careful not to roll it for too long (like 10 seconds). Likewise, the ignition switch; starter button; and, high beam switch can all stay. If you have signal lights, the signal switch can stay (but you have to change the little bulbs in it if equiped).

If you do not have signal lights and want to install some, you will need to change out the light sockets on your running (tail) lights and marker (parking) lights on the front - plus wire in a signal switch - simple. I have the diagram for the install.

Well, that's about all I can think of for now. Just remember this about your new electrical system. If you take the time and don't shortcut, your electrical system will be worry free, easy to maintain and add on to. But if you short cut, I promise it will be the one item that every day makes your truck a miserable piece of garbage from hell that you will hate to drive and work on. So, take your time and do it right- NO used replacement components or wire! I'll be glad to help where ever I can

Remember the 7 P's...."Poor Prior Planning Provides **** Poor Products" Do the planning and the install will be a breeze!

 

Thanks guys, will do some reading. I figure having a degree in EE this should be a breeze.

-Willie

 

Oh God, not an engineer!

 

Ohh Funny funny!

 

I just converted a positive ground 6V to a 12V negative ground with some new gauges without cutting the dash or adding sunpros. PM me and I will save you some money or inform you about the problems that I ran into.

 

Theres lots of way to do it - many have been discussed here already. If you've got a different good idea how about sharing it with everyone here on the boards?

 

I've been lurking here on and off for about a year now but having worked with Model T Fords, I've run across the 6 vs. 12 volt issue before. One thing that often happens over the years is when someone decides to buy new battery cables because the old ones are starting to look ratty. Down to the local auto store they go and buy some cables off the shelf that are the right length. Problem is, these are 12 volt cables which are lighter gauge than a set of 6 volt cables and therefore can't deliver the necessary juice to the starter. You might want to check into this before you spend money on the 12 volt conversion.

On the other hand, 12 volts is often preferred simply because of the convenience when dealing with replacement parts, e.g. lights, etc. Me, I haven't seen the need yet but ya never know...

 

HI WMF6 Welcome to FTE

I'd start a new thread to introduce yourself to everyone (and so you can post pictures of your truck)!

The point about the battery cables is a good one. If you "lean" on your 6 volt started for a few seconds too long with the smaller cables, you will no doubt either fry the cables or the starter. A 6 Volt accessory requires TWICE the amperage to produce the same amount of work as the same accessory in 12 volt.

And not to be contradictory to a newbie right off the bat, I will however provide this statement from "Battery Low in Charge" troubleshooting procedure in the 1949-1951 Frod Truck Shop Manual - Page 351, as food for thought - quote:

"If the resistance (voltage drop) is equal to or less than that specified in the test [External circuit resistance test for low battery], the battery is low in charge due to improper operation by the owner. Excessive night driving or use of accessories, insufficient operation of the vehicle, accidental discharge of the battery (lights, ignition, radio, etc. left on overnight), improper starting procedure (flooding engine, not using choke properly, etc), or too heavy a grade of motor oil for the local climate could take more current from the battery than the generator can replace. Instruct the owner in proper operation of his vehicle."

End quote!

Bad owner, BAD!

And don't even think about putting an electric fuel pump (about the same as driving with the lights on all the time) on the truck.

In case you didn't read it between the lines, what this means is that the 6 volt battery and charging system originally installed on these trucks is SO MARGINAL, that if your motor oil is too thick, or you have to run the defroster or drive with the lights on for any length of time you are going to run down the battery....could get a dead battery!

Car manufacturers went through the significant expense and change to upgrade to 12 volt electrical systems in 1956. There's a reason - this is it.

 

That's good stuff, Julie.

Another reason for the OEM 12 volt change was increased compression ratios and larger engines beginning to be built in the mid fifties, putting even more strain on starting and charging systems. Electric accessories like power windows, seats, and air conditioning were beginning to be seen on the option lists more prevelently, and as noted, the old 6V systems could barely keep up with what they had been doing.

 

Points well taken folks. I grew up with a '51 F5 which I still have (using it for parts as needed for the F6) and one thing we didn't have to do much was use the lights and the one time I did drive in the dark the headlights were not that impressive and it brought back memories from my childhood of riding after dark on roads with no reflective edge markings, non-reflective traffic signs etc. Am I dating myself? Fact is I've been on the fence about switching to 12V myself in the case of this rig. My Model T's can stick with 6 volts however.

 

I'm still in the keep it 6 volt camp, but if it was a daily driver it might not take long to change my mind. You do have to keep after the contacts to be sure everything is clean, you can't afford to drop any of those scares volts. The LED taillights help because they draw less current so have less voltage drop on marginal contacts and leaves some amps for other uses.

Another advantage for the car companies has been hinted at, but you could get by with about half the copper in your car. A few years ago there was a lot of talk about the car companies going to 24V or higher for the same reason.

 

I also am still in the 6v mode,...and I got an electric fuel pump,.....and I use to do a lot of night driving,........and I keep a spare battery in my "Trunk O Tricks" in the back of my 51 Panel. BAD BAD BAD , SUPER BAD OWNER. I have had to swap to a fresh battery 2X's this year. One time on a hot August afternoon and the other on a cold February night. I could see it coming both times. It is just plain PRO-CRAS-TIN-A-TION ( sloth in 5 sylibles ) that is keeping me in 6v. I think I have had 8-10 people stop me at red lights to tell me I got no rear lights. That is my biggest motivater to upgrade to 12v. I guess I am going to need to just stop driving the thing around and get to the things my truck needs and deserves. Its a good truck, but it has a bad owner,
Hence... I never get tired of reading 6 to 12 v threads

 

As you live and breath John, the walking truth!