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    • #57995
      singer
      Member

      I have a 1959 Singer Gazelle Series III. The water temperature gauge only partially works. Let me explain, when the ignition is off the needle goes to 230 degrees (this is correct), turn the key on the needle goes to 90 degrees (this is correct), as the engine heats up the needle stays on 90 degrees (this is not correct). The gauge is NOS, replaced because the other gauge did the same thing, sending unit is new, grounded the temp gauge, and ran a new wire from sending unit to gauge. Any suggestions to get this gauge operating?

    • #65099
      impbarn
      Member

      I don’t have a manual on the Gazelle, but on the Smiths gauges used on the Imp and Alpines the temperature gauge would default to the lowest temperature when the key is off. So, what I’m going to say may be invalidated if the temperature sensor is not a NTC type, and the gauge is not a wound heater type. You’ll have to step through each component and validate them.

      Start with your voltage regulator first. The voltage regulator should be outputting around 10 volts on average. The original is a bimetal strip, so it won’t be easy to read with a digital meter. It needs to have a good ground as well.

      Assuming that this temp sensor is a negative temperature coefficient thermistor, then you should be able to check it with an ohm meter under controlled conditions (out of the car, in a pot of water) using a thermometer as a comparison. That would validate the sensor. NTC sensors start with a high resistance at low temperature, and decrease resistance as the temperature goes up on a curve.

      Then you need to validate the gauge itself. Smiths gauges I’m familar with are wound resistive heated. (The Gazelle may be different, you’ll have to let me know… but most cars of this time period used a Smiths gauge with this basic technology for instrumentation.) The NTC sensor allows more current to flow as the sensor gets warmer… this makes the heater in the gauge warm up, and the needle move toward the hot direction.

      Without a variable power supply, its difficult to test the gauge itself. (You could always bench test the sensor with the gauge out of the car.)

      Finally validate that they all work together. Basically find out if its wired right.

      Starting at the ignition switch.
      With the switch on there should be power the voltage regulator input terminal.
      The output of the voltage regulator goes to the gauge on one side.
      The other side of the gauge goes to the sensor.
      The sensor is grounded to the engine and completes the electrical path.

    • #65107
      singer
      Member

      Thanks Eric,
      Info appreciated. Probably should install a voltage stabilizer to achieve the constant voltage.
      Rod

    • #65109
      impbarn
      Member

      Rod,

      Yes, the voltage stabilizer is essential for Smiths bimetallic gauge technology. The dynamo charges the battery greater than 12 volts, so a stable voltage is key to proper operation of the gauges.

      I know Moss Motors has a solid-state version, it should work in a pinch, but its not the same connections as the ones used on a Sunbeam.
      Sunbeam Specialties carries the correct one.

      good luck…

    • #65112
      mikephillips
      Member

      If you go with a solid state version of the regulator make sure you get the right one as they come in either positive or negative ground and don’t swap back and forth.

    • #65113
      singer
      Member

      Thanks Mike,
      I have a negative ground one from a MGB. Singer was converted from positive to negative ground, so should work.
      Thanks, Rod

    • #65238
      singer
      Member

      To let you know I solved my gauge problem. The problem was with the sending unit, it was faulty, and none are available, anywhere, to match that gauge. So I took the ‘guts’ out of a MGB gauge and carefully fit them in my gauge, a bit of retro-fitting, swapping out the faulty sending unit to the corresponding MGB sender, hocked it all up and everything worked. Thanks to all for their helpful tips. Rod

    • #65991
      anosh
      Member

      I know Moss Motors has a solid-state version, it should work in a pinch, but its not the same connections as the ones used on a Sunbeam.
      Sunbeam Specialties carries the correct one.

    • #66248
      janius
      Member

      The gauge is not properly grounded. Old Smith’s gauges absolutely required a good ground for the gauge housing.

    • #66250
      singer
      Member

      Janius,
      Thanks for this tip. My problem was a faulty sender in the water jacket. I jerry-rigged my gauge to use a MGB gauge and sender. I transplanted the B gauge into the Singer gauge holder. You would be hard pressed to see a difference.
      Thanks, Rod

    • #66251

      Rod,
      Good to read that you solved the problem on the Gazelle.
      I didn’t follow this dicussion earlier, but now have a question for Eric:
      What is the excact difference between the Moss and SS voltage stabilizers? I have used the Moss one without a problem (at not yet a problem?).
      Robert

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