Just installed a used gauge cluster in my F2. I am converting from 12V back to 6 volt. Ran into a few problems:

1. The temp gage reads halfway between cold and hot when engine started cold, then gradually rises to almost full scale. Do I have suspect sending units? Only one was hooked up when I got the truck, have since hooked up both in parallel, I assume this is correct? Shorted to ground, slowly falls to "cold".

2. Oil pressure reads nothing. I know these flathead V8s don't have a lot of pressure but the 12V gage read 40+ at start up, barely off the peg now. Shorted to ground, gage rises slowly to full scale.

3. Circuit breakers on the gage cluster go in series with the amp gage, correct?

4. Anyone have any luck locating keys for the ignition? I suspect the switch I bought has the wrong key. Won't turn the cylinder at all.

I looked for old posts on this but didn't turn anything up. Sorry if this is redundant, but I'm stumped.

Thanks!

Tom

 

1. The temperature gage senders are a series connection. The sending unit in the left head should have two terminals and the one in the right head has one terminal.

2. Does the oil pressure rise when you increase engine speed? I'd say the best thing to do here is connect a mechanical gage and see for sure what you really have for oil pressure. I've found the easiest way to get to the sending unit connection port is through the transmission cover. You can also put a tee at the oil filter inlet.

3. The stock amp gage does not have any connections. The wire from the battery (starter solenoid) simply passes through a loop on the back of the gage then goes to the circuit breakers. When the electrical systems are converted to 12 volt neg gnd the wire is often reversed through the loop otherwise the meter reads backwards. For pos. gnd. the wire passes through the loop from the drivers side toward the passengers side. Be aware that there is no overcurrent protection for this wire and the ampmeter loop is a likely place for a short to occur. A short in this wire can cause a disastrous thermal event in your truck.

4. Locksmith shop?

 

I've seen key blanks on eBay.

I wonder if someone put a non-standard oil pressure sender on the truck when converting to 12V?

Also, when converting TO 12V, it is common to put a CVR (constant voltage regulator) in the feed to the gauges. It drops voltage from 12V down to around 6v, would probably cut 6v down to 4 or so. That would explain why everything is reading low. You will need to remove it if it is there. Looks kind of like a circuit breaker.

-- Ross