Temperature Gauges

[Johnjo]

Can someone please tell me how a "mechanical temperature gauge" with the capiliary tube works ? am i right in thinking pressure !
Are they as good as the more conventional all electric type ? or are they to be avoided at all cost !




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[aztec]

yep, you're right. they're ok when accurate (and generally are) i seem to remember you can alter the needle to read right if a little off.

electric ones are "tuneable" with either different sender units or resistors inline to compensate.

i'd always go for electric as the wiring is easier to run than the capilliary tube.

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[Johnjo]

Thanks Steve, a mate wants to fit a simple temp gauge into the raw water system on his engine, and this seemed to be a low cost option, so thought i would ask here as i have no experience of the mechanical type !


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[supermalc]

As expansion occurs with temperature rise, the mechanical gauges are operated by the expension of the mercury (I think) in the capiliary tube. They are usually accurate, and the most reliable, however the tube can be prone to fracture or damage, which is why the electric ones are so widely used.

All electrical gauges are voltmeters of one sort or another.

<hr width=100% size=1>Malcolm. My opinion is not universally accepted, but is usually right.

 

[aztec]

there's a good chance that the raw water cooled engine may run cooler than it's fresh water counterpart.

you may need to fiddle with the temp sensors, his best bet is go for the ford type (they are colour coded) until you find the one that suits. go for 2nd hand ones, as the new ones are about 15 quids each.

regards steve.

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[fishermantwo]

Mike, I'm not sure why your mate wants to measure the raw water temperature. I actually do this on my fishing vessel. I bought a electronic indoor/out door thermometer with 3 metres of cable. The temperature sender is just taped to a section of brass pipe for the auxillary motor (Kubota). The sender is insulated with foam etc so that the engine room temperature does not effect the thermometer. I use it to measure sea water temperature for tuna fishing. It also measures the cabin temperature by flicking the switch over and also has a digital clock, all for much less than an automotive temperature gauge.

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