thinking of converting to 12v

H

hueyhoolihan

Well-known member
i don't want to convert to 12v, but if i find it necessary what is minimum number of 12v electronic components one would need, other than a 12v battery, a 12 voltage regulator and a 12v starter?

what say ye?
 
J Franklin said:
Light bulbs, coil, You shouldn't ever find it nessasary though.
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i'm beginning to suspect the previous owner may have increased the compression ratio to a point where a 6v battery will simply not turn the engine over.

as it now stands a new 6v battery will click and groan a little, but that's about it. if i remove a couple of spark plugs it will turn over very slowly a couple of times before clicking. if i remove all the sparkplugs it will turn the engine over like a sewing machine. ...hence my suspicion. but, it's also possible that the battery cables and ground and the ground wire from the engine to the firewall are poor. i'll be addressing that too, before making my final decision.

i will soon test the compression and if my research is accurate (it may not be) and i find the compression is, let's say, more than 115PSI on average, i will be very suspicious.

BTW, in the event a find it necessary to run a 12v system, it crossed my mind that it might be worth while considering the insertion of a resistor or two inline in the wiring harness somewhere to reduce the 12v to 6v to avoid addressing componentry like bulbs, heater fan, radio, etc.

...just a hope... ha
 
You can buy voltage reducer units that mount on the guages themselves for the voltage drop requirement. There is also the polarity change to consider. Resistors are fairly cheap, but are best used on constant current devices where the voltage reduction they provide will be constant. You'll need higher power rated resistors however.

Generally I'm a purist, but I went over to the dark side (figuratively not literally) a few years back and converted to 12v, primarily for the brighter tailights. Not everyone understands American turn signals Down Under and I wanted lights that were not just bright enough to understand, but bright enough to get the attention of distracted footy mums.

The LED globes available now might overcome the need for this......
 
The second page of the Techno-Source link below has a number of articles on 6 to 12V conversion. That said, many here have good service with a 6V system after insuring grounds are good, wiring and connectors are good.
 
Sounds like I’m not the first guy pulled toward 12V by the promise of brighter lights and a less dramatic starter groan.
 
Fix your battery cables, starter, and / or starter solenoid. 6V will reliably start a car with 125 psi cranking compression pressure if the parts are in good condition.
 
38 coupe said:
Fix your battery cables, starter, and / or starter solenoid. 6V will reliably start a car with 125 psi cranking compression pressure if the parts are in good condition.
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This. No need for the hassle of a 12v conversion if you have new 2/0 battery cables and ground cables with clean connections. Couple the big cables with an Optima 6v battery, and that will turn your engine over all day long.
 
Not only do I clean the frame for the ground cable, I use a star washer in between the parts. Good connections and large cables do the trick.
 
How about a picture of your vehicle, or at least tell us what year it is? I doubt the compression is too high because the combustion chamber shape limits the compression ratio. Check the things others have suggested. Include having a good shop check out the starter (or borrow one to try that you know is good and try it). ADD YOUR GENERAL LOCATION TO YOUR PROFILE!


Charlie Stephens
 
did compression test and all cylinders were between 90 and 100 psi. so am assuming the engine is pretty much stock. it has 24 head nuts per head. and am guessing its a 221ci or 239ci displacement.

it was a show car owned by a gentleman that passed away in the last two years and ended up for sale at a consignment shop in the bay area. the odometer shows a little more than one thousand miles on it and am guessing it was reset to zero when the car/engine was restored, whenever that may have been.

i will be grinding the lovely paint down to bare metal on the firewall where the positive battery terminal is grounded. the paint is still there and pristine from the restoration. i will also be grinding the paint off the firewall where the motor is grounded. the paint has not been ground off the firewall there either. and at both locations there is a star washer used that was (optimistically IMO) intended to cut through the thick paint and undercoat to create a sufficient connection, but i suspect that that may be my problem.

the consignment shop installed an 8v golf cart battery (weighing about 100 lbs!!) with no other changes that DOES turn over the engine, but i plan on running with a 6v electrical system or in the event i can't get the 6v to work i will go to 12v...there will be no 8v battery.

car is a 1941 Super Deluxe Convertible in Lachaven green. was a national AACA winner of something or other, but has probably fallen into a bit of mechanical disrepair as of late. it would not run and so could not drive it before purchase and took a gamble. bought a set of points from NAPA and had it running in a day, fortunately.

other issues involve massive steering lash (slop), probably kingpins and spindles need replacing, something in both doors clang every time i hit a medium sized bump in the road. hard starting after engine is warm. most of the gauges that involve electricity don't work...stuff like that. not really anything major.

the tires are good old bias plys, the brakes are very solid and confidence inspiring as is the transmission and clutch. i'm not a car show guy. i like to drive my old cars across the country on my yearly visits to see family in Ohio. i'm located in central coast California.
 

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hueyhoolihan said:
did compression test and all cylinders were between 90 and 100 psi. so am assuming the engine is pretty much stock. it has 24 head nuts per head. and am guessing its a 221ci or 239ci displacement.

it was a show car owned by a gentleman that passed away in the last two years and ended up for sale at a consignment shop in the bay area. the odometer shows a little more than one thousand miles on it and am guessing it was reset to zero when the car/engine was restored, whenever that may have been.

i will be grinding the lovely paint down to bare metal on the firewall where the positive battery terminal is grounded. the paint is still there and pristine from the restoration. i will also be grinding the paint off the firewall where the motor is grounded. the paint has not been ground off the firewall there either. and at both locations there is a star washer used that was (optimistically IMO) intended to cut through the thick paint and undercoat to create a sufficient connection, but i suspect that that may be my problem.

the consignment shop installed an 8v golf cart battery (weighing about 100 lbs!!) with no other changes that DOES turn over the engine, but i plan on running with a 6v electrical system or in the event i can't get the 6v to work i will go to 12v...there will be no 8v battery.

car is a 1941 Super Deluxe Convertible in Lachaven green. was a national AACA winner of something or other, but has probably fallen into a bit of mechanical disrepair as of late. it would not run and so could not drive it before purchase and took a gamble. bought a set of points from NAPA and had it running in a day, fortunately.

other issues involve massive steering lash (slop), probably kingpins and spindles need replacing, something in both doors clang every time i hit a medium sized bump in the road. hard starting after engine is warm. most of the gauges that involve electricity don't work...stuff like that. not really anything major.

the tires are good old bias plys, the brakes are very solid and confidence inspiring as is the transmission and clutch. i'm not a car show guy. i like to drive my old cars across the country on my yearly visits to see family in Ohio. i'm located in central coast California.
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Stay away from the 8 volt batteries. They are a patch and don't solve the basic problem(s). They also introduce other problems. Your car looks great. If you do go 12 volts a good electrical shop should be able to rebuild your original generator (which is what I would recommend). Your car looks great, thanks for the photos. UPDATE your profile with you general location!

Charlie Stephens
 
ithanks.

i didn't do anything to make the car what it is, i simply bought it...ha

i have no desire to have an 8v system. for one thing, i plan on putting in an E-Fire electronic distributor. and they offer only a 6v positive ground or 12v negative ground version. so it will be either 6v, 12v or nothing.

i'll be working on the car this summer with hopes of having it reliable enough to travel to Ohio to visit family in the September/October timeframe. planning on traveling a northern route this year, through Yellowstone and maybe taking the ferry across Lake Michigan and then down to Columbus, OH.

i do this sort of thing every year for the last fifteen years. in previous years i've driven my motorcyle numerous times, my 1953 MG and my 1967 Jaguar MK2. ...great fun! :)
 
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This has to be the #1 problem people have with old cars. Converting to 12V is fine but you have to remember that the car did work with 6V when it was new so what has changed? So, to check it you need to run a "voltage drop test". You set the meter to the scale closest to the car's voltage. Then you put one lead on one end of a cable and the other lead on the other end the same cable and crank the engine or turn the lights on, whatever that cable or wire goes to. You "shouldn't" see much of a reading, preferably close to zero volts. The reading you see is the loss of voltage through the cable. You can check the starter or any other component this way to, it's fast. There are lots of YouTube videos on this subject. This is the correct way to diagnose an electrical problem. If something worked on 6V and nothing has been changed like the compression ratio then something is wrong in that circuit. Maybe the starter is tired, a voltage drop test across the starter will tell you. You test every cable, component and ground in the starter circuit and then add up the voltage loss readings.
 
You have a beautiful looking car. I have seen many beautifully restored cars that didn't want to crank on 6V. Many restorers forget that Ford put bolts and nuts at critical electrical connection locations before painting the cars, leaving bare spots for the cables. Another item that causes problems is loose clamp nuts on the studs on the starer and the starter solenoid. Disconnect the battery, then one at a time take the battery cables off each stud and snug the lower nut that holds the stud secure providing a good electrical connection (do not gorilla tight, you will break things). Then reattach the cable and again a good snug. Clean anything that has corrosion or paint. Another popular problem location is the end of the starter where it connects to the oil pan, those were bare when Ford built things, many restorers put a pretty coat of paint that acts as an insulator. As mentioned above make sure you have bid diameter battery cables proper for 6V, 00 (double aught) gauge.
 
I wouldn't have the battery grounded to the firewall. Run it to the engine. Best is run it to the starter housing, but I don't think Ford did that.
 
Flathead Fever said:
This has to be the #1 problem people have with old cars. Converting to 12V is fine but you have to remember that the car did work with 6V when it was new so what has changed? So, to check it you need to run a "voltage drop test". You set the meter to the scale closest to the car's voltage. Then you put one lead on one end of a cable and the other lead on the other end the same cable and crank the engine or turn the lights on, whatever that cable or wire goes to. You "shouldn't" see much of a reading, preferably close to zero volts. The reading you see is the loss of voltage through the cable. You can check the starter or any other component this way to, it's fast. There are lots of YouTube videos on this subject. This is the correct way to diagnose an electrical problem. If something worked on 6V and nothing has been changed like the compression ratio then something is wrong in that circuit. Maybe the starter is tired, a voltage drop test across the starter will tell you. You test every cable, component and ground in the starter circuit and then add up the voltage loss readings.
Click to expand...

so i set my multimeter on DC and set the scale to the closest scale i've got to 6v and/or 8v, and then put one probe on the battery terminal that's used for ground (positive in my case) and the other probe on the starter housing and hit the starter button, the amount of voltage shown on the meter is the amount i'm losing? and in my example i'll be seeing how much voltage i'm losing due to a poor grounding of the starter? if so, this is just what i'm looking for. and i hope i can use it to measure how much voltage i may be dropping to the distributor too, as the car becomes much more difficult to start once the circuitry warms up.

and i'm assuming that the length of wire or span of circuitry i test is determined by where i set the multimeter's probes and nothing else. the only other necessity that that circuitry must be carrying a current when testing.

for as it is, the 8v battery that is in the car turns the starter very well, but a 6v will not turn it at all, but will if i remove four or five sparkplugs! ha
 
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