40 ford standard oil guage question

[bigcatfelix]

i AM RUNNING A STANDARD INSRUMENT CLUSTER IN MY 40 COUPE, RUNNING 12 VOLT SYSTEM. HAVE VOLTAGE DROP (TO 6 VOLT) ON THE BACK OF THE OIL PRESSURE GUAGE. I AM RUNNING LATE MODEL V-8 W/SENDING UNIT FROM ENGINE,GUAGE MOVES BUT DOSEN'T READ, IT GOES TO 0. WHAT HAVE I DONE WRONG ANY IDEAS ????? THANKS BARNERS

 

[41ford1]

Are you using the sending unit from the flathead or the one on the late V8? The gauge should show 0 with the ignition off or the ignition on and the engine not running. If the guage moves to 50 PSI then there is a short between the sensor and the guage. If you are using the sensor from the late V8 it may be a switch for a light. I am Using a Standard Motor Products PS-60 sensor in my flathead. It corrolated with a mechanical guage I used to check it.

 

[19Fordy]

The original 40 sending unit was made to operate on 6 volts. I doubt if the late model (12V, I assume) sending unit you are using will operate on 6 volts also. Reinstall the stock 40 sending unit and see what happens.

 

[bigcatfelix]

Thanks for the tip. I bought the PS-60 it worked perfect !!

 

[41ford1]

Bigcatfelix,

Glad that worked for you.

19fordy,

You are correct Ford used the 6 volt gauge system in to the '80s. They used a voltage reducing module after going to 12 volts in the '50s. You can still get this reducer at a parts store or auto recycler (PC) instead of using the Runtz. I did not know that when I did my gauges. I used 3 Runtz for oil, temp & fuel and a high wattage 60 ohm resistor for the volt meter. A new reducer runs about $50.00.