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| | | | Joined: Jul 2014 Posts: 8 New Guy | | New Guy Joined: Jul 2014 Posts: 8 | So I just purchased a 1951 GMC truck with a chevy 235 engine and a new 6v battery sitting in it but not hooked up. The previous owner passed away years ago. The truck has a 12v alternator, large white resistor on the firewall and the coil "-" to the distributor. I'm thinking I need a 12v battery with a negative ground hook-up. Just need some reassurance, I don't want to fry my gauges. | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 |
What you describe is a safe bet.
Is there a resistor on the input lead on the fuel gauge?
Most likely, all light bulbs are already 12v.
If you have a heater and the motor is 6V, you might want a resistor on the input lead. Maybe someone will comment on the placement of this resistor (before the speed-control switch or after the switch).
| | | | | Joined: Jul 2014 Posts: 8 New Guy | | New Guy Joined: Jul 2014 Posts: 8 | Thank you! The fuel gauge pegged full so i'll need to get a resistor but nothing smoked. | | | | | Joined: Mar 2010 Posts: 10,275 Renaissance Man | | Renaissance Man Joined: Mar 2010 Posts: 10,275 | Does the gauge peg with the ign switch on? That usually is a symptom of no ground from the top of the sending unit. 12 volts to a 6 volt gauge should not damage the gauge or sending unit, it just won't read correctly.
Carl
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | Does the gauge peg with the ign switch on?
[1] That usually is a symptom of no ground from the top of the sending unit.
[2] 12 volts to a 6 volt gauge should not damage the gauge or sending unit, it just won't read correctly.
Carl [1] Yes [2] No damage to the sending unit (simply described as a variable resistor); but, the 6v gauge might be wounded/fried. A 12v to 6v runtz-style reducer on the input side of a 6v fuel gauge is recommended by most people. | | |
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