49 F-1 electrical system and gauges

[Art Newland]

I’m jumping the gun a bit with this project as I have some big jobs to complete on my 30 coupe, but I want my pickup to be safe to drive in the meantime. I thought to begin with, that I might be able to “fix-up” the existing wiring enough to please me but it was just too far gone. The PO had purchased a new aftermarket harness, but never installed it. I really didn’t want to install it yet either, so I chopped out all the wiring and made up a simple harness to cover the basics of running and starting the engine, charging the battery, and brake lights.

[Art Newland]

Really , all you need is power in from the battery, a wire to energize the starter solenoid, wires from the armature and field of the generator to the regulator, then from the Battery terminal of the regulator connected to the power from the battery. Obviously you need a way to get power to the distributor and energize the starter solenoid, so I used an inexpensive ignition/starter switch from O'reilly's.

[Art Newland]

None of my gauges except the ammeter did anything, so I pulled the cluster and started investigating gauge info here on the barn, they are a little mysterious after all, and my truck has been converted to 12 volts negative ground which also adds to the equation. The temp gauge had been (crudely) chopped out and a mechanical version hacked in there, but interestingly enough, was connected to a conventional electrical temp sensor.

[Art Newland]

In some of my searching for info on gauges, I read that Ford had continued to use pretty similar gauges well into the 70's, and that they were still 6 volts. A quick look on Craig's list found a local guy parting out a 1970 Ford pickup, so I hooked up with him and bought the instrument cluster for $25. After pulling away all the plastic outsides, sure enough, very familiar looking gauges down in there and a voltage regulator to power them.

[Art Newland]

I installed a set of generic auto-part store gauges so I can keep an eye on the 239 and make sure it’s happy, but I’d really like to have all the stock gauges working… and a working fuel gauge would be handy. So that’s where I’ve started. In my pile of goodies that came with the truck, was a fuel tank sending unit. I’ve read that the repros aren’t very good, and sure enough, it didn’t work. I took it apart and the tiny wire that goes to the sending unit wire connection was not connected because of a poor solder connection. I soldered it up properly, and using a 12 volt battery connected it all up.

[Art Newland]

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In my pile of goodies there was also a “runtz” style voltage regulator, so I experimented with it as well as the one that came with the ‘70 gauges.

https://www.youtube.com/watch?v=sf09eT0tOpQ

[Art Newland]

The runtz VR worked better with the old gauges and the 70 Ford unit worked best with the 70's gauges... not too surprising I guess. I think plan will be to try and move the old faces to the new gauges, except the oil pressure gauge, it looks in good shape but time will tell.

[rotorwrench]

I always considered a mechanical gauge to be one that uses no electrical signal to operate.

The modern gauges aren't so much a specific voltage as they generally have a voltage regulator to keep the input clean from electrical variation and spikes. Even modern alternators put out some rough electrical voltage/current. The old King Seeley current regulated type gauges didn't survive the 50s but they were excellent instruments and could take just about anything the generator could throw at them.

If you have a pacemaker, the Doctors advise not to go near a running auto or aircraft engine. You can ride inside the car but that's as close as they recommend you get. They just throw RF and other magnetic variations out there under normal operation.

[Art Newland]

Originally Posted by rotorwrench

I always considered a mechanical gauge to be one that uses no electrical signal to operate.

Yes, that's the funny part, the temp gauge hacked into it was a thermo-bulb type unit, the the sensor end was wrapped around the screw of the stock (electrical) sensor! This truck is like "farmer-fix" central and is full of very interesting repair jobs. I never really thought about it when buying a truck, that where and how it was likely to be used, that how it would've been maintained... or lack of.

[1948F-1Pickup]

I finally got all mine up and operating. (12v conversion,
Delco 12si alternator and custom wiring harness)
I'm using a reducer(12-6 volt to run the gauges and
heater blower) specifically intended for the job.
http://74.91.146.189/catalog.html

The crappy Vintique fuel sender was the last part of
the puzzle. Once that was trashed & replaced, its been
smooth sailing and everything works correctly.

[Art Newland]

Anyway, I don't know exactly when I'll get back to all this, but thought I'd document what I'm doing here and maybe help someone else through the process, and for you guys that know about these things to keep an eye on me to make sure I don't do something stupid. I love this kind of project and look forward to getting into it soon.

[Art Newland]

Originally Posted by 1948F-1Pickup

I finally got all mine up and operating. (12v conversion,
Delco 12si alternator and custom wiring harness)
I'm using a reducer(12-6 volt to run the gauges and
heater blower) specifically intended for the job.
http://74.91.146.189/catalog.html

The crappy Vintique fuel sender was the last part of
the puzzle. Once that was trashed & replaced, its been
smooth sailing and everything works correctly.

What did you end up with for the sender unit? The one that's in my truck may work, I haven't got that far yet. I know it's the incorrect one because it does't bolt down properly.

[1948F-1Pickup]

The new one (that works right) came from Mid-Fifty Parts.
I'm guessing they source it from ACP. I think mine has a
yellow plastic cover over the guts. Pretty sure it's the same
unit though..... Mid-Fifty lists it as part # 1607-3555
Full 14 ohms Empty 94 ohms $45

http://www.acpdealer.com/product/fue...11-2/version-2