My original gauges on my 52 F-1 are not working so I'm going one at a time to get them operable. Oil pressure has a bad sending unit and in looking around while they are plenty available the price from various sources seems to be 45-50 dollars. Sounds high for a sending unit but is that all thats available?

 

It's King-Seely constant voltage (CV) type vs. Stewart Warner, AC, and the rest of the world. Maybe you could score a "used but good" (UBG) unit from somewhere by Googling the part number.

 

You should note that all the gauges, except the AMP gauge, are internally the same (just a different face). As for testing the gauge itself, The Ford Shop manual states to test the gauge, supply it with 1.5 Volts DC and it should read about 1/2 way.

The stock sending unit uses the The King-Seeley (Ford Stock) principle. These sending units supply a full 6V through the heater wire in the gauge in the form of a square wave with the duration of the "on" being the variable determining the gauge reading. The longer the duration, the more the needle moves. It is this full 6v of current which heats the bi-metallic strip in the stock gauge that causes the gauge to read via a small gear train (that may some adjustment). Most after market sending units are simply a variable resistor. Therefore, the sending unit's signal doesn't heat the bimetallic strip in the gauge as much. Unfortunately, attempting to calibrate an after-market sending unit and a stock gauge is impossible due to the differences in the principle of the signal.

You are not going to find a new sending unit significantly cheaper than what you have already found. Your mileage may vary with used sending units and gauges. I have found may gauges that have succumbed to being fed 12V by a quick and dirty battery swap or a difficult jump start.

 

Already tested and found bad sending unit for oil pressure.Temp I have to check tomorrow since I found the original sender tonight.
Fuel gauge was sunk float and amp gauge will be wired to my 150 amp powermaster alternator.I said heck with it and ordered the op sender and new float.That's enough for tonite

 

I guess you know about re-routing through the Hall Effect loop then, and wire sizing for 100 amps.

 

I know how it works but don't know about wire size.

 

100 AMPS at 12V, you are looking at 4 gauge wire. If it is 150, you may be getting in to 2 gauge territory depending upon the lengths of run you have. I'd doubt either of those will route nicely through the stock gauge. Also, I think the stock gauge maxes out at 30 Amps...

 

AWG 6 for 150 amp alternator, but if you feel lucky, AWG 8. The largest wire that will pass through the loop is AWG 4, which is what I have.

 

They operate on the same principles, but the Temp gauge operates backwards from the OP gauge.

I have to wonder if the belt will support a 150 amp alternator. What loads do you have that you need so much power? Admittedly the alternator will only put out what is needed.

 

I bought two of them at the same time. They gave me $20 off for getting two.One for my 40 Buick with straight 8,AC,big stereo,Zirgo electric fan,one wire hookup optima battery..Same with Ford, easy hookup,Optima,big electric fan,no air or stereo Both have 6V starters. Spins em fast.On the 40 I can crank it in low gear and by the time it fires I can shift to second.Also today I found the OG wire to the sending unit. Grounded it and the gauge started down from full to about 3/4 then started bouncing up and down.I'll try the sending unit tomorrow.

 

Yea so far the single 3/8' belt is doing fine. Really don't have much draw. Get a short little chirp when starting cold.