12 Volt Conversion Kit Install! Flathead Ford

I show you how to convert 6 volt positive ground to 12 volt negative ground. I use the Kit from VintageAutoGarage.com
Make sure you check them out, I also have shirts for sale! Comment below to let me know if you would like a shirt.

[@harrycatrell1471]

Thank you for a very well done session, Zac! That was some great information, presented so it could be understood! Enjoy the weekend! Be safe!

[@WiredCustomsSpeedShop]

Thank you! I’m trying to step my game up! Lol. And you too!

[@billwill2881]

I have a 1951 Dodge pickup truck one ton or half ton the smallest one has a 6 cylinder I want to convert it to a 12 volt system give me some information on what to buy

[@williamsickner2206]

Safety! How to protect the electric system and vehicle? A lot of the older vehicle and tractors I work on have or need 6v to 12-volt conversions. Also, the systems may have been modified from original and things may have been added. What are the best practices regarding fuses, fused links, breakers, etc to design and lay out an overall safe system that won't be a fire hazard? I have yet to find a good video on this basic concept.

[@bartgoins1782]

Great video. Thanks for the info, instructions and the source for the conversion kit.

[@WiredCustomsSpeedShop]

No problem! Thank you for watching

[@davidhaarala2341]

It sure would help with cold morning starts hoping you don’t run out of juice.

[@WiredCustomsSpeedShop]

That’s definitely a big plus, or worrying about the battery dying on a hard start

[@captainmorgan240]

Hello. Im going to convert my 49' to 12v negative ground and install an electrical fuel pump. Tips on best way to get power to the pump only when the engine is running? Otherwise i guess i could install a manual switch for the pump, but that doesnt feel ideal. Ive ordered the kit from Vintage auto garage with the powermaster. Cheers

[@WiredCustomsSpeedShop]

You could have a key that switches a relay for the pump or the ignition switch could switch a relay, just make sure whatever switch you use that the pump power doesn’t actually run through the switch

[@JayAce82]

Awesome info! I think I found you & subbed a bout a year ago when I got my grandpas 46 Ford. I just got it into the shop to start seeing how healthy it is to see how much I need to rebuild. I’ve watched a lot of your Flathead stuff at least twice! Hasn’t ran since ‘93 & was garage kept in WV, frame is perfect but cab has some rust.

[@WiredCustomsSpeedShop]

Nice! Sounds like a great project. Thanks for watching my video

[@smed395]

Great video. I’ve been contemplating this for a while now but after seeing it layed out this way I’m not so hesitant. Keep up the good work.

[@WiredCustomsSpeedShop]

Nice! I’m glad I could be of some help!

[@lowhunggarage9519]

same here

[@jameslewis5569]

Nicely done. Love that fire truck!

[@WiredCustomsSpeedShop]

Thank you James!

[@OurF6FarmTruck]

Zac, I have a 1948 F6 farm truck that I want to convert from 6V to 12V. I am a retired electronics technician, so I understand both wiring and circuits. I can “get into the weeds” if you will, to better understand how the gauges and circuits work. The fuel, temp, and oil pressure gauges are straight forward, and I can get a 12V to 6V conversion block that I can use for them. Here are some additional questions. 1. I am considering using the alternator you are describing as it bolts directly on the engine without having to monkey with mounting brackets. With only one wire and a 90A capability, what gauge wire will I need to use to connect it to the battery and then to the main fuseblock? According to an online wire gauge, it suggests that I need to use 4 gauge wire for a 100A system. Is that what you used for your truck? 2. I notice that you are running your alternator wire directly to the battery. Does that mean that the alternator has its own internal relay so that it doesn’t draw power from the battery when it isn’t running? 3. You feature a diagram of an “ammeter” at 11:29 on your video. That isn’t an ammeter, it is a voltmeter. Not the same thing. An ammeter must be placed in series with the line in order to measure current. A voltmeter is placed across the line to measure the voltage. The diagram is for a voltmeter. If the gauge is what you depict, it doesn’t measure current, and I would have to place a series resistor to use it to measure 12V instead of 6V although a 60Ω 10W resistor is doable if I could find one. A typical ammeter has a shunt resistor in parallel with the meter itself which is only rated for a small current capability. The main power is routed through the shunt allowing only the small current to the meter to read its proportion of the main current. The greater the current range, the smaller this resistance value must be. To use the 60Ω bimetal coil shown in the diagram as a true ammeter, it will draw 100ma at 6V. that means that in order to measure 50A at full scale, the shunt must carry the remaining 49.9A while producing a 6V voltage drop to run the meter. To do this, the shunt must have a resistance of .12Ω. I will have to cut the shunt resistance to .061Ω to achieve the 100A range I will need to use with a 90A alternator. The problem with this concept is two-fold: First, if I drop 6V across my ammeter, then only 6V is available for the rest of the system. I would have to run my battery and alternator to 18V in order to keep 12V to the system. The next problem is that dropping 6V across such a circuit consumes nearly 600W of power. Both are impractical and not going to happen. I need an ammeter that will only drop a few tenths of a volt and consume only a few watts of power at full range. That was what I was expecting the ammeter to do until I saw your diagram. I will have to rethink my idea of how to make this work. 4. I need to find a period correct cartridge fuseholder, but so far the ones available online are for the newer style plug-in fuses and they are marked for marine use. Do you know where I can get a cartridge fuseholder that I can label for my own circuits? I appreciate the video you made. It has given me insights into what I need to do to accomplish the conversion. Please reply directly to my e-mail below. Thank you. Brian Yerka Blackfoot, ID [e-mail]

[@tydavis4867]

Good afternoon Wired Customs. I appreciate this video, thank you kindly. When doing the 6V to 12V conversion, Vintage Auto Garage (they are a huge help as well) recommends keeping the voltage regulator in place removing the wire for the generator and keeping the other wires still in place to the voltage regulator. I will be going to an alternator. My question is, can the voltage regulator be replaced with a new 6V voltage regulator or since I will be converting to 12V can I, do I, or should I replace it with a 12V voltage regulator and hook all those wires that are connected to the current 6V one for the exception of the generator wire. I know this seems like a lot to my question. I’m just trying to sort it out so it’s efficient, reliable, and safe. I have not started the conversion as of yet. Thank you in advance for your response. Stay safe, blessed, and well. 1950 Mercury Club Coupe.

[@UncleMas]

Awesome video. Im just starting a conversion on my wifes 41 Dodge D19 and this is exactly what I neede to see!

[@cesarherrera3339]

Hello I am new to this this conversion kit, that I will be installing on 1958 Cadillac 62 serious, this coming week, I would like to know a little more on how to install the 6 volt reducer Module.

[@johnrodgers3788]

on the 48 -49 wiring diagram there is one yellow wire passing under the batt ( amp) gauge to the circuit breaker that goes to the battery side of the 6v solenoid which has 3 posts on it, in the video, there are 2 wires from the fuse box. I believe the larger wire would go to the batt side of 12v starter solenoid. What post does the smaller wire go to? The old 6v solenoid had 3 posts one bat, one starter, and one starter button.

[@duanethieme4186]

Great video, thank you! I am working on 1947 truck, I have a converted to 12 volts, generator, wipers, dash cluster etc,.. it currently has the 6 volt 6 volt sending units oil, temperature, fuel, work/read ok with 12 volts? Thank you!

[@russellcarl3643]

Great video's, thanks for all of the video's you post. I ordered the 12 volt conversion kit from Vintage Auto Garage for my 1939 Ford Deluxe Coupe. I;ve got everything installed. The lights work as well as the horn and the dash lights and gauges but, when I push the start button, nothing happens. I really don't understand how the start button functions with only one wire but, that's the way it is designed. That wire goes to a relay under the dash mounted on the firewall. That relay was not in the kit so it was not changed. I have checked and rechecked my wiring and everything looks correct. Do you have any ideas for me ? That relay is spotwelded to the firewall. Should I replace it? If so, do you have a part number or description for me. Also you recommend a fuse in the wire going from the start button to the coil but, I'm not sure what amp fuse to use.

[@WaxMeister]

Hi Zac, I'm almost done a complete wiring of my '35 to 12V including using new harnesses from Third Gen. One item that I'm confused with is the wiring of the Foot Starter Button. I'm doing away with the modern Ignition/Starter switch to reinstall a new Foot Starter Button for a more traditional look. feel and function. At the moment I'm stuck and confused reading the old Ford Schematic sheets - could you please tell me where the two wires on the Foot switch are connected? I've used the Vintage Garage kit you used on this video - many thanks for your help.

[@SPAMOK]

Thank you so much for the video ! 2 questions, at this point would I need to put in a new fuse box? I still have the old glass fuses. I'm converting my 53 MercuryMonterey. Keeping the generator using the MSD ready to run distributor. Would I use the same starter solenoid that you show at the beginning of the video?

[@anthonycorradi774]

Did I miss the ignition coil installation?

[@WiredCustomsSpeedShop]

Sorry for the confusion this video is a little older now, I installed this in another video

[@AnythingArtisticbiz]

Thanks so much I have a 1950 dodge I wanna upgrade. How long did that take you to do ? Great job on walking us through the process 👍

[@guillaumeamann5696]

hello I am French and I own a ford f1 v8 of 1950 that I want to switch to 12 v. would you have a diagram for the connection of gauges? thank you very much for your videos and explanations

[@Atlas.X9X]

Great information. Thanks for sharing.

[@WiredCustomsSpeedShop]

Thanks for watching!

[@fredwicker5400]

Excellent video

[@WiredCustomsSpeedShop]

Thanks Fred!

[@JimHinrichs]

recently bought a 1950 ford 2 door. sitting since 1991, going to do a 12 volt conversion, positive ground to negative ground. have 12v to 6 v step down and need to buy a wiring kit. my question: as I swap ground polarity, do I have to swap the polarity on the back of the gauges? electrons will be going opposite direction. do the gauges care? leave the sending unit on same connection? sending unit transits a resisted ground to gauge, which gets a hot volt from the key switch. do I swap inputs on the back of gauges? Am I over thinking this? watched loads of videos while at work and have not stumbled into the answer, thank you in advance

[@davidhaarala2341]

We had to have a core heater plugged in to get the old Ford farm truck going in the winter. Wyoming truck.

[@WiredCustomsSpeedShop]

Oh wow. I’ve never messed with a Flathead in the true cold, I couldn’t imagine how hard it was to start

[@davidhaarala2341]

@@WiredCustomsSpeedShop Had to finesse the choke . If nothing else, Grandma could pull start us with the John Deere. Started that with a hand crank. That flat bed is now in my garage undergoing a frame up. I am relying on KZbin videos like yours for how tos. Thanks for helping me rebuild my Holley 94. I am proudly subscribed to your channel.

[@WiredCustomsSpeedShop]

@@davidhaarala2341 that’s awesome! And thank you for watching I appreciate it

[@slick-px4pq]

Great video! What about the coil?

[@WiredCustomsSpeedShop]

Thank you! In a previous video I upgraded the distributor and coil, I should’ve put a part of that in this video

[@joegustin7158]

Great Job Any Thing On Ing Or Coil Has To Be Changed

[@WiredCustomsSpeedShop]

you will need a 12 volt coil and ballast resistor

[@stevendavis554]

yo Ive got a 50 ford shoebox and its a rats nest under the dash could you tell me how many step downs and where I need them to convert to 12v ill be doing new lights all around. thanks man and killer video super helpful.

[@Jeff-tf5hj]

I have a 1954 ford crestline, converting to 12 volts, using vintage auto kit. Hooking up the reducer to the gauges, (2), it has two terminals , one with one wire, the other with one two, one which goes into the dash illumination bulb….. question…. What side do i put the stepped down 6 volt wire to? And do i remove/ cut the one i i replaced? Or leave them all hooked up, Please help.

[@davewin77]

what fuse would be recommended for the horn relay's battery wire?

[@nathanrice1796]

Very clearly explained.

[@WiredCustomsSpeedShop]

Thank you!

[@jameslangford4748]

Saving for the kit. Thank you Zac. Does Speedway sell that kit ?

[@WiredCustomsSpeedShop]

Sorry Soeedway does not sell the kit, right now Vintage Auto Garage is our best option

[@jameslangford4748]

OK, thank you. I am starting to save for the parts - thanks to you I'll get the right stuff. Thank You very much ! @@WiredCustomsSpeedShop

[@WiredCustomsSpeedShop]

@@jameslangford4748 No problem at all feel free to ask any questions during installation as well

[@MrJeep75]

Awesome video

[@WiredCustomsSpeedShop]

Thank you!

[@tomdorow8177]

Great video! Your explanations are very clear. I have a 47 Mercury flathead so just starting research on doing a conversion. Since my gauges don't work at all I plan to use an after market company to replicate the original design but be 12vDC. I didn't see any mention of changing the coil. Does that need to be done? Thanks!

[@LonMartin-q4u]

Hey I have a 1950 Plymouth flat head six what do I need to change it from a six volt to a 12 volt

[@godiambad]

What about the siren?

[@will-Rynerson]

Hey Zac, I need to do an aftermarket fan and I’m wondering if you know temp range for the sending unit and the make/model for the 12volt system. And do I need to change the dash temp gauge or can I just run it to the voltage reducer then to the dash temp gauge?

[@WiredCustomsSpeedShop]

If you have an electric temp gauge on the dash you can still buy a stock temp sending unit and run it to the voltage reducer, for the fan you will have to run it on a separate temp sending unit, typically a good electric fan will come with its own sending unit, the early ford store and MACS would be the places I go to find a OEM sending unit for the gauge. But all that being said, I still recommend running two mechanics temp gauges, one for each head, since you could have one water pump fail and not the other and have no idea, by 1949 ford fixed this with the dual temp sending unit to one electric gauge on the dash, I don’t remember what year vehicle you have but that’s food for thought

[@will-Rynerson]

Awesome thanks I’ll get a stock one. Can I place the fan sending unit in a different bolt hole? Also, I’m getting no power to dash lights, blinkers, headlights, starter. Can that beck a bad circuit, breaker, or ignition switch? I doubled checked all my connections for the replacement wiring harness that I installed.

[@will-Rynerson]

Hi Zac, I hope you can help me out. I have completed wiring everything in double checking my wiring now the truck cranks. But I’m only getting 5.6 V to the coil and it says that I need to be getting 12 V to the coil. I check the ignition switch And it has 12 V going in but to the coil I’m only getting 5.6 V. I’m not sure why that changed. Also, the headlights and tail lights aren’t working properly. I follow the directions on the wiring instructions but it doesn’t seem to be working right. If you have any ideas, I could definitely use them.

[@speedracer3033]

Do you not have to change the distributor and coil?

[@WiredCustomsSpeedShop]

Yes you do, here is the full explanation kzbin.info/www/bejne/q5CqdGyYotB6j5o

[@aroundlinemen]

Nice video!

[@WiredCustomsSpeedShop]

Thank you!

[@lowhunggarage9519]

Great Video! Thank you! What do you think would be the hardest part for a new guy???

[@WiredCustomsSpeedShop]

Honestly the whole swap is really easy, the only part I would consider hard is adjusting the fan and powermaster belt, I needed 4 hands to get it all right and the belt tight at the same time!

[@lowhunggarage9519]

@@WiredCustomsSpeedShop what about the coil what do you recommend

[@WaxMeister]

Just started working on my 12v upgrade but, every time I start I find something else that need attention before I get further into it. Today I upgraded all the 6v bulbs and discovered a number of issues with wiring and fasteners - I guess that's a good thing (it's a 25plus year old restoration)! Replaced the bulbs, flasher and relays... tomorrow I'll be under the dash doing the 12v-6v gauge component and the inline fuses where needed. Wish me luck!

[@chrisjansen8294]

Can I ask why it is so critical to change the battery cables and not reuse them? I understand your reasoning on the chassis ground strap. I just spent quite a bit on 1or 0 gauge battery cables. Probably should've decided what voltage I was going run first... lol

[@WiredCustomsSpeedShop]

A good majority of the original cables were too small even for 6 volt, it’s a common upgrade on a 6 volt to get bigger cables, if you have the right side cables and not the original then there is no need to replace them

[@chrisjansen8294]

@@WiredCustomsSpeedShop ok thanks, I really appreciate the response. I'm getting ready to drop the oil pan in my wife's 1949 f1 to clean out any sludge after watching several of your videos... lol The motor is still in it Any tips or recommendations on the job or what the best pan gasket?

[@WiredCustomsSpeedShop]

@@chrisjansen8294 nice! I just use the fel-pro gasket, just make sure to put some black rtv on the edges by the rear main

[@duanethieme4186]

@@WiredCustomsSpeedShop My understanding is a 12 volt system requires half the size of wire vs the 6 volt system., due to the doubling of the volts.

[@aquilesmartinez2398]

I have a 1949 Mercury 8, my set up is positive ground (reverse polarity) do you have a video? or a diagram as to how to wire it up? what needs to be changed?

[@Wayz5145]

Would you start with just removing all the old wires or do you do a piece at a time? Is there a distributor from a 12 volt donor vehicle that would work on a 1955 223 ?

[@stevenmacinnis418]

super great videos awesome

[@WiredCustomsSpeedShop]

Thanks Steven I appreciate it!

[@jameslewis5569]

Actually, I do have a question. So I bought a 47 Ford Super Deluxe with the 12V conversion already done. I can't get it to start and I think it has something to do with the push button and maybe a fuse but I can't locate more than maybe 4 fuses total under dash and in engine compartment. There should be more, correct? Like a fuse bank or block somewhere? I have installed a new starter, battery, and ignition solenoid which all seem to be working via my volt meter. The battery is coming in at 11.97 volts however. So, maybe that is it? Otherwise, I think it must be a blown fuse that I can't locate. Any ideas? Thank you so much!

[@WiredCustomsSpeedShop]

For the question about more fuses, there “should” be more, but I see a lot of the times people don’t fuse everything they should, check for power on the positive side of the coil, also some ignition systems can’t start unless the battery is at 12.4 volts

[@jameslewis5569]

@@WiredCustomsSpeedShop thank you so much! I will go look at those items and get that battery charged back up to 12.4. Thanks again and I'll post an update 🙂

[@WiredCustomsSpeedShop]

@@jameslewis5569 right on no problem at all

[@jameslewis5569]

@@WiredCustomsSpeedShop Zac, I have an update. Charged battery to 12.6V and checked the coil. Coil is registering at 11.97V. Still no start, no crank, no click, nothing from the push button. It just seems dead. I think the brake lights are not coming on either. Rest of lights are working. Thinking it is a fuse but can't find more than about 5 fuses throughout the whole wiring system. Thanks for all you do to keep our old Flatheads running!

[@WiredCustomsSpeedShop]

@@jameslewis5569 jump the battery to the starter relay and see if it will crank over then

[@pmotorsports8276]

What stops the starter from turning backwards?

[@WiredCustomsSpeedShop]

The direction of the spin is determined by how the electric motor is wound, so it will still spin the correct direction no matter the polarity

[@pmotorsports8276]

@@WiredCustomsSpeedShop good to know

[@diyeasyandfast650]

Can you please post the links for all the parts you use in this project? Thank you!

[@MrJeep75]

I would keep all the original stuff for safe keeping

[@WiredCustomsSpeedShop]

I definitely have a couple shelves just full of OE parts

[@davidhaarala2341]

So that set up eliminates the need to change any bulbs?

[@WiredCustomsSpeedShop]

Actually I changed the headlight bulbs, I should’ve put that in the video, the previous video I mentioned that, my bad!

[@d.brownjr.4845]

I have 50 model 8n ford. I want to fix the amp gauge no I can't find any wires going to it. Pos.ground. 6 v. How would I wire it up? I want to keep the 6v. System. Or would it be better to have a volt gauge?

[@WiredCustomsSpeedShop]

I’m more of a fan with volt gauges, but if you want to keep an ammeter then you hook it up to the positive output on the generator

[@d.brownjr.4845]

@@WiredCustomsSpeedShop only one wire? Nothing to the switch

[@d.brownjr.4845]

@@WiredCustomsSpeedShop would I hook up the volt meter the same way

[@d.brownjr.4845]

@@WiredCustomsSpeedShop I haven't bought a new gauge yet. Wanted to see if the old one worked. If not, I'll go with the volt gauge. I'd like to hook up all my light too. How can I do that read my meter with volt or the other.

[@WiredCustomsSpeedShop]

@@d.brownjr.4845 the ammeter only needs one wire in most vehicles, the ammeter works like a coil and has an internal wirer wrapped around the prop that moves the needle, it works off of amps in the wire, the volt meter will need a power and a ground to operate

[@jessiecurl1843]

What did you do with the wires that were connected to the generator? The voltage regulator on the firewall and its wiring?

[@johnrodgers3788]

there are 4 wires on the voltage regulator a ground, an amp, a field, and hot ( power) from the circuit breaker under the dash. The grd , amp, and field all go with the old generator as they are no longer needed. The stock hot wire is yellow and should be disconected on the circuit breaker making the voltage regulator powerless.

[@MrCorynick]

What is the benefit to doing this? I don't really fully understand the point of 12v conversions

[@duanethieme4186]

There are many more 12 volt parts accessible than 6 volt parts, and easier to add accessories.

[@paulomartins190]

Saudações do Brasil

[@tonymorgan1978]

What about changing all your bulbs!!!

[@WiredCustomsSpeedShop]

There is another video explaining what you need for this conversion and I go over bulbs on that one

[@bladerunner6282]

ahhh....i think i'll stay with my 6v system. :)

[@WaxMeister]

Hi Zac, picked up the kit from VAG (arrived today), noticed you installed a turn signal switch I already have one, do I need to change it for a 12V one or will the voltage reducer work? I also bought the digital ignition - is there anything I need to be aware of installing it - do you have a video for that installation? Finally, what bulbs might I chanve from 6 to 12V. Thanks! Exciting!

[@WiredCustomsSpeedShop]

Great! Make sure to get the manual that VAG sells for the conversions, in that manual they have a spread sheet of part numbers so you know what bulbs you need to buy to convert them over to 12 volts. As for the turn signal switch it really varies on what switch you currently have, safest option is to replace it, another option is to replace the flasher for the blinkers and add in a fuse and change it wiring to negative ground, certain turn switches will work fine when switching it then others will not, I haven't found a good pattern to why, has to be different components for the voltage types I am guessing, if you mean a pertronix then you have the easiest ad best ignition, I do not have video of installing one as of yet but plan to! Just make sure the gap is right and you are good to go

[@WaxMeister]

@@WiredCustomsSpeedShop awesome, thanks for your response - I'll order up the switch then. By the way, might you have a video where you adjust the steering box on a '35 ford? Thanks again!

[@WiredCustomsSpeedShop]

@@WaxMeister I do not but as we speak I am rebuilding a steering box off of a 47 ford, that might help some

[@WaxMeister]

@@WiredCustomsSpeedShop what has me confused is the Brass nut/bolt that appears to be the adjustment does not look like other adjusters where the centre adjuster is held with a screw driver while the locking nut is ether loosened or tightened in the adjustment process. I'm shy to just crank on it without knowing. I have a repair manual on order but there's no guarantee it covers that adjustment issue. If you post the steering box rebuild I'll watch it in the mean time I'll continue with my research and/or wait until the repair manual arrives. Thanks again for taking the time. Appreciated!

[@WaxMeister]

@@WiredCustomsSpeedShop Well, got the adjustment done, the 'brass' blind bolt turned out to be a steel bolt. I took it to my mini-lathe and turned it down so the adjustment screw could be tightened properly - 100% improvement!