So I have some used gauges, how do you check to see ..

[AntiqTed]

So I have some used gauges, how do you check to see if they work ?

I got a box lot of car stuff at an auction .

I have these 5 gauges by different companies.

I just want to see if they really work !

I have a train transformer that will put out 16 volts DC and a multimeter.

I suspect I can't check the oil pressure gauge because it's mechanical.

Is there a place were I can get instructions ?

THANKS !

[JamesR]

Quote

I have a train transformer that will put out 16 volts DC and a multimeter.

 

 

That fuel gauge might be 6 volt.

[AntiqTed]

I forgot to say that I suspect all these gauges were replaced with 12 volt Moon Eyes brand gauges. I suspect this because I have some of the boxes . My train transformer will go from 0-18 VDC .

[TerryB]

Is your train transformer fo HO type trains?  Some under low load will not regulate voltage very well over its operating range.

[TerryB]

The fuel gauge will probably require some resistance in the circuit to ground to check it.  Many gauges need some type of variable resistance in series with the gauge to get a reading.

[wldavis]

Ted,

These are my thoughts:

Fuel gauge - you will need to attach an appropriate fuel level sender plus a voltage (6 or 12) to test this.

Oil pressure - if it has electric terminals on the back, it will need a sending unit.  If it has a threaded fitting on the back, it will need a section of tubing and a liquid (oil) running through the tube under pressure to test.

Water temp - if it has electrical terminals on the back, it will need a sending unit to test.  If it has a threaded fitting on the back, it will need a section of tubing filled with some liquid (I cannot recall what this is),

                       plus a fitting that screws into the engine block to test.  These fittings plus liquid in the tubing for water temp gauges are sealed units.

Amp meter - this can be tested by attaching this meter between the battery (+ terminal if neg gnd or - terminal if pos gnd) and the "load" (all the rest of the circuit).

 

You may be able to find some instructions on-line at the gauge manufacturers website.

 

 

[joe_padavano]

The temperature and fuel level gauges use a sender that is a potentiometer. You can test the function (though not the calibration) of those gauges by simply using a pot to replace the sender. Start with resistance high and slowly turn it down until the needle moves. Fuel gauges will typically use one of three senders - 0 to 30 ohms (empty to full), 0 to 90 ohms, or 240 to 33 ohms. The latter is most common with aftermarket fuel gauges.

[padgett]

By the 180F center temp  and 120 psi max oil I'd make those post 1966. The 90 degree gauges look earlier (or more weathered. I recall Midland aftermarket and SW is Stewart-Warner.

 

An HO train transformer may put out 0-16v but is probably a trash signal, a 12v battery source through a 0-500 ohm pot would be much better. I'd probably rig a resistor in a parallel circuit to limit current. Gauges are usually very low current (ma).

 

An air source should twitch the pressure gauge.

 

I always looked for an 80 psi oil pressure gauge, much more useful. Chev Power said not to exceed 65 psi or you could damage the bearings. For a Jag the magic number was 40 psi at 3,000 rpm.

 

 

 

Edited November 14, 2019 by padgett (see edit history)