[Shelby1]

I have finally got around to adding a direct reading temp gauge to my DD ,which is no longer true since I am now retired ,but it has to be done as the stock gauge is very erratic and would be a pita to change( 91 Bronco) so I decided this would be my best choice .I decided to check the calibration of two gauges that I had ,one I found in a utility body in a wrecking yard, it is still in the box that it came in from Moon Equipment . I have no idea how old it is but it does have "Made in the USA" on it.The other was a Sun made in China. Well I decided to check how accrue they were. Pan of water on stove and wife's candy thermometer..............Sun was off 25 degrees and Moon 10 degrees. Well i wondered if this was common so I called up a Buddy of mine who happens to be manager at a local Pep Boys parts house . Well of course he did not know but he told me he had 3 different makes of gauges that had been returned for various reasons (missing parts,would not fit application)and I could use them for comparison just as long as I returned them so he could get credit for them . Well i did ,one was off by 16 and the other two by 20 to 25. All made over seas.
O.K. now my question have any of you run in to this? Have you checked the gauges you bought before you installed them? If you checked them and they were right ,right out of the box what kind were they?
Next...Have any of you taken a gauge apart ( face or lens ) and realigned (bent) the needle or pulled it off and reset it in the right place or is this too anal ?
Kenny
You can't license or legislate intelligence !

[302 Z28]

After market gages have never been real accurate otherwise they would be very expensive. In industry a deviation of + or - 3 degrees is standard in temperature measurement. To get any more accurate than what we have now for auto application is cost prohibitive.


You really cannot bend the needle or pull off the face and realign. That would destroy the zero and span of the gage. You are expecting a cheap gage to be as accurate as a high dollar gage.

Vince

[sqzbox]

I have a sun pro in my truck. say's 180* I have a 180* thermostat, and I checked the temp. at the cap when it opens and it's 180* Sold at Advance auto. Maybe, your wife's candy thermometer is off.

[Shelby1]

Originally Posted by 302 Z28

After market gages have never been real accurate otherwise they would be very expensive. In industry a deviation of + or - 3 degrees is standard in temperature measurement. To get any more accurate than what we have now for auto application is cost prohibitive.

Vince

Yes , this is about what I thought. I did contact a former co-worker from my civil service days (I was a avonics tech) since my first post and he said much the same as you (he was a instrument calibration tech) as he said -or+ 5 degrees. He was not surprised at what I found in the wide variation of readings that I found. He said as long as you know how much a gauge is off and that is taken in to account when you read ,should not be a problem. Which is what I did as I went ahead and used the Moon gauge.


sqsbox, Yes I thought about the candy thermometer being off so being the anal person that I am (some times!!) I checked it against two other thermometers, one a real Mercury and one of the new ones with the new stuff that they replaced Mercury with.The one with real Mercury is a Lab grade that was used to check temps in a photo processing operation. The readings from them was the same as the candy one . Dead on....
I was very surprised to find that there was such a wide variation in the temps that I got. This means that any after market gauge should be checked BEFORE it is installed so it is known what the readings mean.
Many Thanks!!
Kenny
You can't license or legislate intelligence.