How do I tell if my car has been converted to 12v?

[Terranova]

Gentleman, before you say "look at the battery" a little background.

When we purchased this '36 fordor six years ago, we were told it had been converted to or was being converted to 12v. The battery we took out of it when we garaged it was, indeed, a 12v battery. But I don't think conversion was completed.

So, my questions.

Where do I start? The battery box and trace out from there?

How do I tell if it's currently set up pos or neg?

Plans are to replace the stock motor with a warmed up 8BA.
Should I just remove everything and start over/fresh?

I hope to make this a weekend, road trip, kind of car (more driving than just the local cruise/parade)
Should I (here it comes) convert to 12v or go back to 6v?

Thanks guys.

[corvette8n]

If it's original wiring or a hack job, I'd put in a new wire harness, at that point you can decide if you want 6 or 12 volt.

[Juergen]

In an old car, about the only things affected are the lights, gauges, coil and perhaps a radio. Safest to test with 6 volts. With a 6 volt battery, positive ground, turn on the lights. Are they bright? if yes then the lights are 6 volts. Does the amp gauge show discharge, if yes then positive ground is correct. Are the gauge lights bright? Then they also are 6 volts and I suspect the coil is too, but only an engine start would verify this. Is the radio old and directly connected (no dropping resistor) to the battery? If yes, then it too likely is 6 volt (assuming a costly internal conversion was not attempted). If the radio is new, most likely it is 12 volts.

[JSeery]

What type of coil is on the engine, original style mounted on the distributor or a later "can" style? If it is the can style, which post is connected to the distributor, + or - ?
Does it have a generator or alternator? Check some of the bulbs, headlight, tail light, are they 6v or 12v? How about posting a photo of the engine compartment.

[FortyNiner]

It is unusual to convert to 12 volts and retain a generator - most install an alternator. That would be your first check. Remove a headlight an check the voltage rating as a second check. The condition of the wiring harness will dictate the need for replacement as will your desire for accessories like phone chargers or a newer radio. If you want the new stuff, 12 volt is the answer.

[Terranova]

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Engine compartment the day we bought it.

[flatheadmurre]

That one is most likely 6v since it has a 3-brush generator with what looks like a stock cutout on it.
If it still has the helmet distributor with the builtin coil...it´s another sign it´s still stock 6v positive ground.

[Terranova]

The cut out is the grey/silver thing on top of the generator?

So, if someone just hooked up a 12v to it to run it, then they could have possibly melted some stuff? Pretty sure I saw something melted drip one of the three times we had it running.

[flatheadmurre]

Generator will not pass out from it...but ignition and gauges will not survive if ran for more then a very very short period...

[40 Deluxe]

Check the battery cables. The positive terminal is bigger than the negative. Which is bigger, the ground cable or the 'hot' cable? If the ground cable has the bigger terminal, it's positive ground, so still six volts.

[flatheadmurre]

If it´s still stock 6v and ran on 12v for a short time...gauges probably survived...the KS gauges are tough.
I would get a new/rewound coil (that´s what usually melt first) and go with the stock 6v setup if you don´t plan on using any addons that absolutely need 12v.

[54vicky]

Originally Posted by 40 Deluxe

Check the battery cables. The positive terminal is bigger than the negative. Which is bigger, the ground cable or the 'hot' cable? If the ground cable has the bigger terminal, it's positive ground, so still six volts.

I do not believe that is a good indication as the 12 volt battery can be hooked up with positive ground if used to start only harm would be to voltage sensitive items I would think

[Flathead Fever]

If your going to update it with an 8BA with higher compression heads I would convert it to 12V.

Just looking at the generator I don't believe the 12V conversion was completed. The light bulbs should be marked for use with 6V or 12V. Somebody probably stuck a 12V battery in it just to see if it would crank. If you want to drive it the way it is you will probably need a 6V battery and hook it up back up to a positive ground. Then there is no guarantee the charging and ignition system was not damaged when they hooked up the 12V? If your going to convert if to 12V you might as well start now and not waste your money on a 6V battery.

If it has been converted to a negative ground. the negative battery cable would go to the engine block or starter mounting bolt. The positive cable would go to a starter solenoid and then continue on to the insulated terminal on the starter. That would just mean the starter has been converted to 12V negative ground. You would need to check every component to make sure the positive and negative wires have been swapped. Then you need would resistors to drop the voltage to a 6V radio, horn and coil. Then replace all the bulbs. Replace the generator with a later unit Re-wired for 12V (12V field cols installed) and install a 12V regulator from a 1957 to 1964 Ford.. The starter works on either 6V or 12V.

As far as the wiring, it should all be replaced. Which direction you go, either reproduction wiring harness or making up your own depends on if you modify the vehicle with an alternator, modern gauges, electric fuel pumps....... If your going to stick an 8BA in it, its not going to be original anyway so you don't need to pay for a reproduction harness.

You might ask some of these guys if they prefer an 8BA or a 59A in a '36 Ford. Everything sticks out further on the front of an 8BA so the belt can clear the late style distributor. You want to make sure this does not create any radiator clearance issues. What are the pros and cons of one engine over the other in a '36 Ford. Don't give up on the 21 stud motor. I just went for a ride ride in a '34 pickup with a stock 21 stud one and it was a lot of fun. They made speed equipment for those too.

[rotorwrench]

Folks put engines of the 8BA family in the 35/36 cars but it requires the right stuff. The package that the 1949 through 51 Mercury cars came with is the closest fit. I'm not sure about the fan and pumps but they might work with adapters for the pump engine mounts. The pan and the clutch/bell housing equipment will work.

If your old LB engine is a good core then it can be rebuilt as easy as any other flathead and it already fits. As far as 12-volt conversions go, I'd put it back to 6-volt positive ground. A two brush generator has more amp capability but the Fun Products voltage regulator that looks like a cut out can make an old 3-brush work out OK. I would only convert to 12-volt if I were to street rod the thing with modern amenities and I don't do street rods much. Traditional hot rods of the 40s are cool enough for me.

[40 Deluxe]

Originally Posted by 54vicky

I do not believe that is a good indication as the 12 volt battery can be hooked up with positive ground if used to start only harm would be to voltage sensitive items I would think

But how many 12 volt conversions run positive ground? I haven't seen any. So if the ground cable fits the positive post of a battery it's a pretty good indication the car in question is still a 6 volt system!
That, plus the picture of the original generator, tells me that this is a 6 volt car.

[Terranova]

Well, I already have this motor, which I'm told is a '53.
It's got the pumps with the motor mounts
The duel belt crank pulley
EAB heads
It's been fit with an alternator, which may or my not be changed
I was told (yes I know) that it has a 4" merc crank, which I have yet to verify with my own eyes.
I have a duel carb manifold I'd like to put on it.

[Mart]

Haven't read all the replies, but one of the easiest indicators is to look at the light bulbs.

Mart.

[rotorwrench]

That motor looks to be set up with some pickup or truck stuff like the pumps and the rear half bell. The pan looks like a center sump. The truck pan is a rear sump type but it is deeper than a Mercury 8CM pan and has the dust seal plate that bolts to the pan. The Merc pan is the best fit with the wishbone under the car. Truck pumps may work out OK but they set the engine up a bit higher than the Merc pumps do. The mechanical fan is the hard part to figure unless someone has some pointers. The 36 had the fan on the generator but all the 8BA family had them down front. A person has to watch the radiator clearance due to it's angle and the way the top hoses attach.

If you want an electric fan then 12-volt positive ground might be the best approach. Everything has to be considered when altering things from stock OEM configuration.

[blucar]

The question (s) regarding 6v verses 12v have been pretty well beat up so I'll stay away from making a comment on that topic.
The application of an 8BA/8CM engine into a '36 is a very simple procedure if you use Ford truck and/or '49-50 Merc water pumps and pump spacers under the pumps. I would suggest that you use the '36 log style of exhaust manifolds,
I have attached a pix showing an 8BA engine in my friends '37 truck..

[Terranova]

So the spacers are to buy some space between the crank pulley and the crossmember?

If it's just the standard donuts then the. Igor sits to low?

[cas3]

what you want to shoot for is the nut at the end of the crankshaft should line up with the original hand crank hole as if you wanted to hand crank to start it. i know you wont be doing that, but its where the engine should sit as it did originally

[JSeery]

Not sure what a 36 requires, but these are what I use on the 33/34s. These were a Ford item that was used to retro fit motors.

[blucar]

The '49-50 Merc mount spacer does to things.. The holes in the frame cross-member and the water pumps do not match, therefore the holes in the spacer are offset which requires two bolts.
The spacer raises the front of the engine to allow for the shorter pumps.