ausmini :: View topic - Adjusting a Smiths temperature gauge

the 10.5v might be the problem... it's meant to be 10.0v, though it ought to be easy to adjust by adding resistance inline with the sender. The resistance decreases with temperature, so adding resistance will lower the gauge

Measure the resistance of the sender at the temperature where the needle sits where you want it, measure it at the temperature where it sits now, and add a resistor that equals the difference (sounds right, I think...)

I've just been through a similar problem, my voltage reg is at 10.17V, we are working to sort the gauge, sender and voltage regulator in the meantime I've got a trimpot so I can adjust the resistance to make the gauge sit where you want or as it should, measure the resistance on trimpot and buy a resistor to match.
Info I got from Howard's is on my gauge 50C is 240ohms 140C is 19 ohms, you could use the trimpot with these resistances set to see if the gauge is reading correctly.

all my old Smith temp gauges have small adjusters at the back, sometimes still covered with a plug of cork.
never did it myself but read that you connect it to power and a specific resistor (same value as your sensor at the temperatur your are adjusting for) and carefully adjust until it shows what it should.

I want to lower the needle position on my temp gauge.

My question - Is there a way to adjust these gauges?

gtogreen1969 wrote:

I want to lower the needle position on my temp gauge.

My question - Is there a way to adjust these gauges?

Yes...you can very carefully bend the pointer/needle back and the gauge will read lower for a given input

[PS you can't usually "pull the needle off and reposition it" because of the way the gauge pictured is manufactured].

The needle position can be adjusted. There is/are a slot/s in the back of the temp gauge to adjust the needle position.
(I can't remember if there are one or two adjustment slots in the back)
The 6 dots on the gauge face, 2 under each of the C,N and H correspond to specific water temps but I don't know what they are.
My S has the needle slightly below the N when the thermostat - 180 deg F, starts to open.
The needle centreline is above the LH edge of the N. It has been this way since new.
Are you sure you have the correct sender?
There are a multitude of different senders out there, some genuine Smiths and some aftermarket.

Hope this helps

RonR

Pretty good description of how to adjust a Smiths gauge here:
http://www.mgb-stuff.org.uk/fuel.htm

Author:	gtogreen1969 [ Tue Jul 25, 2017 5:46 pm ]
Post subject:	Adjusting a Smiths temperature gauge
I want to lower the needle position on my temp gauge. My question - Is there a way to adjust these gauges? If not then I was going to pull the needle off and reposition it. My normal running temp is 85-90 deg using an infrared thermometer but needle sits just under the red on the gauge. I want it to sit halfway. The gauge is getting a good steady 10.5v. The sender is the new MKO recommended type. No thread tape used. Good wires and earths. Its been like this for 15 years.

Author:	simon k [ Tue Jul 25, 2017 6:24 pm ]
Post subject:	Re: Adjusting a Smiths temperature gauge
the 10.5v might be the problem... it's meant to be 10.0v, though it ought to be easy to adjust by adding resistance inline with the sender. The resistance decreases with temperature, so adding resistance will lower the gauge Measure the resistance of the sender at the temperature where the needle sits where you want it, measure it at the temperature where it sits now, and add a resistor that equals the difference (sounds right, I think...)

Author:	fuzzy-hair-man [ Tue Jul 25, 2017 11:39 pm ]
Post subject:	Re: Adjusting a Smiths temperature gauge
I've just been through a similar problem, my voltage reg is at 10.17V, we are working to sort the gauge, sender and voltage regulator in the meantime I've got a trimpot so I can adjust the resistance to make the gauge sit where you want or as it should, measure the resistance on trimpot and buy a resistor to match. Info I got from Howard's is on my gauge 50C is 240ohms 140C is 19 ohms, you could use the trimpot with these resistances set to see if the gauge is reading correctly.

Author:	gtogreen1969 [ Tue Jul 25, 2017 11:42 pm ]
Post subject:	Re: Adjusting a Smiths temperature gauge
simon k wrote: the 10.5v might be the problem... it's meant to be 10.0v, though it ought to be easy to adjust by adding resistance inline with the sender. The resistance decreases with temperature, so adding resistance will lower the gauge Measure the resistance of the sender at the temperature where the needle sits where you want it, measure it at the temperature where it sits now, and add a resistor that equals the difference (sounds right, I think...) It may be 10v. I was using my old analogue meter and it reads 10.5v - 0v -10.5v. I probably should check and adjust my analogue meter against my digital one first. Maybe a Wombat electronic stabilizer is on the cards. Have you done any gauge adjustments in the past?

Author:	fuzzy-hair-man [ Tue Jul 25, 2017 11:47 pm ]
Post subject:	Re: Adjusting a Smiths temperature gauge
No but as a temporary measure I have my current one reading accurately adding about 38 ohms getting a resistor tomorrow.

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Author:	gtogreen1969 [ Wed Jul 26, 2017 12:20 am ]
Post subject:	Re: Adjusting a Smiths temperature gauge
fuzzy-hair-man wrote: I've just been through a similar problem, my voltage reg is at 10.17V, we are working to sort the gauge, sender and voltage regulator in the meantime I've got a trimpot so I can adjust the resistance to make the gauge sit where you want or as it should, measure the resistance on trimpot and buy a resistor to match. Info I got from Howard's is on my gauge 50C is 240ohms 140C is 19 ohms, you could use the trimpot with these resistances set to see if the gauge is reading correctly. Thanks for that info. My gauge has always read high and it was hard to see the temperature when you are going for a decent fang and you have to look across and workout if it's in the red or above the red. If the needle was in the middle for normal running then it would be a lot easier to see a temperature spike. I haven't taken any ohms readings of the new sender yet at different temps. I just put it in and hoped that would fix it - as you do. The only thing I have done with these temp gauges before is to take the glass off to clean them. I was hoping it is like a speedo where you can pull the needle off and reposition it. Just seeing if anyone has done this before I go braking mine.

Author:	KLAS [ Wed Jul 26, 2017 12:48 am ]
Post subject:	Re: Adjusting a Smiths temperature gauge
all my old Smith temp gauges have small adjusters at the back, sometimes still covered with a plug of cork. never did it myself but read that you connect it to power and a specific resistor (same value as your sensor at the temperatur your are adjusting for) and carefully adjust until it shows what it should.

Author:	gtogreen1969 [ Wed Jul 26, 2017 1:01 am ]
Post subject:	Re: Adjusting a Smiths temperature gauge
KLAS wrote: all my old Smith temp gauges have small adjusters at the back, sometimes still covered with a plug of cork. never did it myself but read that you connect it to power and a specific resistor (same value as your sensor at the temperatur your are adjusting for) and carefully adjust until it shows what it should. Thankyou

Author:	9YaTaH [ Wed Jul 26, 2017 8:08 am ]
Post subject:	Re: Adjusting a Smiths temperature gauge
gtogreen1969 wrote: I want to lower the needle position on my temp gauge. My question - Is there a way to adjust these gauges? Yes...you can very carefully bend the pointer/needle back and the gauge will read lower for a given input [PS you can't usually "pull the needle off and reposition it" because of the way the gauge pictured is manufactured].

Author:	gtogreen1969 [ Wed Jul 26, 2017 8:56 am ]
Post subject:	Re: Adjusting a Smiths temperature gauge
9YaTaH wrote: gtogreen1969 wrote: I want to lower the needle position on my temp gauge. My question - Is there a way to adjust these gauges? Yes...you can very carefully bend the pointer/needle back and the gauge will read lower for a given input [PS you can't usually "pull the needle off and reposition it" because of the way the gauge pictured is manufactured]. Thanks

Author:	miniron [ Wed Jul 26, 2017 7:12 pm ]
Post subject:	Re: Adjusting a Smiths temperature gauge
The needle position can be adjusted. There is/are a slot/s in the back of the temp gauge to adjust the needle position. (I can't remember if there are one or two adjustment slots in the back) The 6 dots on the gauge face, 2 under each of the C,N and H correspond to specific water temps but I don't know what they are. My S has the needle slightly below the N when the thermostat - 180 deg F, starts to open. The needle centreline is above the LH edge of the N. It has been this way since new. Are you sure you have the correct sender? There are a multitude of different senders out there, some genuine Smiths and some aftermarket. Hope this helps RonR

Author:	gtogreen1969 [ Wed Jul 26, 2017 8:05 pm ]
Post subject:	Re: Adjusting a Smiths temperature gauge
miniron wrote: The needle position can be adjusted. There is/are a slot/s in the back of the temp gauge to adjust the needle position. (I can't remember if there are one or two adjustment slots in the back) The 6 dots on the gauge face, 2 under each of the C,N and H correspond to specific water temps but I don't know what they are. My S has the needle slightly below the N when the thermostat - 180 deg F, starts to open. The needle centreline is above the LH edge of the N. It has been this way since new. Are you sure you have the correct sender? There are a multitude of different senders out there, some genuine Smiths and some aftermarket. Hope this helps RonR I bought the sender that John at MKO recommends. My old sender was doing the same thing. This is the one I bought. https://minikingdomonline.com.au/produc ... -cooper-s/ Both old and new are the same sender marked B710. As they sit now the one on the engine is 660 ohms @18 deg. The old one is 850 ohms @ 17 deg. To do a proper comparison i will have to take out the new one then compare the 2 using hot / boiling water. I think i will try the adjustments on the gauge first.

Author:	gtogreen1969 [ Wed Jul 26, 2017 8:36 pm ]
Post subject:	Re: Adjusting a Smiths temperature gauge
I had a bit of a google and found this guy who has tested a new GTR104 / B710. Now i have something to compare to if needed. http://diary-of-mgb.blogspot.com.au/201 ... r.html?m=1

Author:	wild_willy [ Thu Jul 27, 2017 9:48 am ]
Post subject:	Re: Adjusting a Smiths temperature gauge
Pretty good description of how to adjust a Smiths gauge here: http://www.mgb-stuff.org.uk/fuel.htm

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Author:	gtogreen1969 [ Thu Jul 27, 2017 11:20 am ]
Post subject:	Re: Adjusting a Smiths temperature gauge
wild_willy wrote: Pretty good description of how to adjust a Smiths gauge here: http://www.mgb-stuff.org.uk/fuel.htm Thanks willy. Thats what i was chasing. Its a pitty i was out in the shed this morning and missed the post. I worked it out pretty quickly how to do it after taking mine apart. All sorted and fixed. Cheers Here it is at 89 Deg. I could still lower it a bit but at least now the needle is away from the H mark and easier to read when glancing across.