[torqhead]

Alright, got the dash pulled out and the cluster out of the dash. Took it apart and discovered the need has come off the end of the part that makes the gauge work. Pics are attached, anyone have any ideas if I can fix this? If someone knows how to tell me to re-attach the needle, get it in the right position and test the gauge I would appreciate it.

[Formulabruce]

the needle has a "collette" on it and is a "press fit"
Ill say this, a temp "switch" used in place of a "sender for a guage", since it drops a dead short when it turns on the idiot light, or a fan in newer cars can RUIN a guage, if left like that a while.
postive voltage pegs the needle to hot, and gradual grounding ( cooling) brings the needle down.

[torqhead]

Originally Posted by "QUICK-SILVER"

Sounds about right, what you have to do to get the cluster out.

Good luck with it. I'ld try to find another guage, before I took it apart.

Trying to remember what those guages looked like. Wondering what the chances are that the needle has come loose and slipped on the post. Might be wishful thinking.

Hey bud, long time no talk. I finally got my rear in gear now to fix that gauge since I put a new motor in the car and want to ensure I know the temp when I start it up for the first time. As you can see from my last post I found the problem.... Is there a way I can apply power to some of the leads and get the gauge to say 250 degrees, then somehow "glue" the needle back on pointing at 250....

["QUICK-SILVER"]

Don't know why not, but I'd pick a cooler temp to set the needle than 250°F.

If you can find out the resistance readings of the sending unit compared to the indicator marks on the guage, you could wire the guage up with a resistor in the send wire and glue the needle on.
If info isn't published (George might have it though) you can heat the sending unit in a safe liquid and measure resistance at different temps with an ohm meter. You'll have to borrow the better halfs candy thermometer to get accurate temp readings. Just clamp/attach a wire to the send post and do the same to the body (nut and treads). Use heavy enough wire so you don't lose any resistance, then drop the sender in liquid and heat away.
I've got an old quart metal can with block heater out of a diesel mounted to it, that I've been using for years to check thermostats before installation. Plain water gets so hot that it jumps out of the can but straight antifreeze will let you get the temps on up there.
Cooking oil in a "fry baby/daddy" would be pretty safe.
Leave your ohm meter hooked to the wires while you slowly heat the sender, watching it along with the candy thermometer, taking temp and resistance notes as you go.
Then instead of trying to put the needle on with guage potentially moving, pick up some resistors from radio shack and hardwire the guage till your done. Resistors to get the job done will be about 5 for a dollar. That would be safer than trying to glue the needle with the sender in boiling oil.
Go slow with the sender heating so it has time to heat up inside. It takes it a second to catch up with the liquid temps.

It wont take much glue at all. "Gorrilla" brand super glue should hold it forever. You'll want just a smear in the needle hole. Then hold the guage face down while you stick the needle on and the glue dries. You DONT want any glue going back up the post.

Use a battery and wire up hot and ground to the guage. Put the right resistor/s in the send wire back to battery ground and stick the needle on.

Tested readings on the sending unit may be more accurate than published info.
Heating the oil to a certain temp and then lowering the sender in will probably work best. Just start out low and work your way up.


BE CAREFUL!!!!!!!
Any questions we'll be here.
If I had your parts I'd be more than glad to do it for you.
I believe you can handle it though.

[torqhead]

Originally Posted by "QUICK-SILVER"

Don't know why not, but I'd pick a cooler temp to set the needle than 250°F.

If you can find out the resistance readings of the sending unit compared to the indicator marks on the guage, you could wire the guage up with a resistor in the send wire and glue the needle on.
If info isn't published (George might have it though) you can heat the sending unit in a safe liquid and measure resistance at different temps with an ohm meter. You'll have to borrow the better halfs candy thermometer to get accurate temp readings. Just clamp/attach a wire to the send post and do the same to the body (nut and treads). Use heavy enough wire so you don't lose any resistance, then drop the sender in liquid and heat away.
I've got an old quart metal can with block heater out of a diesel mounted to it, that I've been using for years to check thermostats before installation. Plain water gets so hot that it jumps out of the can but straight antifreeze will let you get the temps on up there.
Cooking oil in a "fry baby/daddy" would be pretty safe.
Leave your ohm meter hooked to the wires while you slowly heat the sender, watching it along with the candy thermometer, taking temp and resistance notes as you go.
Then instead of trying to put the needle on with guage potentially moving, pick up some resistors from radio shack and hardwire the guage till your done. Resistors to get the job done will be about 5 for a dollar. That would be safer than trying to glue the needle with the sender in boiling oil.
Go slow with the sender heating so it has time to heat up inside. It takes it a second to catch up with the liquid temps.

It wont take much glue at all. "Gorrilla" brand super glue should hold it forever. You'll want just a smear in the needle hole. Then hold the guage face down while you stick the needle on and the glue dries. You DONT want any glue going back up the post.

Use a battery and wire up hot and ground to the guage. Put the right resistor/s in the send wire back to battery ground and stick the needle on.

Tested readings on the sending unit may be more accurate than published info.
Heating the oil to a certain temp and then lowering the sender in will probably work best. Just start out low and work your way up.


BE CAREFUL!!!!!!!
Any questions we'll be here.
If I had your parts I'd be more than glad to do it for you.
I believe you can handle it though.

Who's George?

["QUICK-SILVER"]

Originally Posted by torqhead

Who's George?

george kujanski is a source of seemingly unlimited knowledge here. Send him a PM and he might just be able to help.

I do believe the self testing will give you a more accurate guage though.

[torqhead]

Originally Posted by "QUICK-SILVER"

george kujanski is a source of seemingly unlimited knowledge here. Send him a PM and he might just be able to help.

I do believe the self testing will give you a more accurate guage though.

Yeah, I was just wondering about when the ign. it turned on temp and oil gauges usually go to the lowest setting. Was wondering if I just applied power to the gauges, which should make the temp go jump to the lowest setting, put the arm on there whether that sets it right or not.

["QUICK-SILVER"]

That would work if you knew what temp the guage started to move/work. Not knowing could have the needle off too far. That's why you need to know the range of the sending unit and match it to the guage. One measurement and one temperature would probably be good enough. Knowing the full scale would tell you how accurate the guage is. Every degree for every mark.

[torqhead]

Originally Posted by "QUICK-SILVER"

Don't know why not, but I'd pick a cooler temp to set the needle than 250°F.

If you can find out the resistance readings of the sending unit compared to the indicator marks on the guage, you could wire the guage up with a resistor in the send wire and glue the needle on.
If info isn't published (George might have it though) you can heat the sending unit in a safe liquid and measure resistance at different temps with an ohm meter. You'll have to borrow the better halfs candy thermometer to get accurate temp readings. Just clamp/attach a wire to the send post and do the same to the body (nut and treads). Use heavy enough wire so you don't lose any resistance, then drop the sender in liquid and heat away.
I've got an old quart metal can with block heater out of a diesel mounted to it, that I've been using for years to check thermostats before installation. Plain water gets so hot that it jumps out of the can but straight antifreeze will let you get the temps on up there.
Cooking oil in a "fry baby/daddy" would be pretty safe.
Leave your ohm meter hooked to the wires while you slowly heat the sender, watching it along with the candy thermometer, taking temp and resistance notes as you go.
Then instead of trying to put the needle on with guage potentially moving, pick up some resistors from radio shack and hardwire the guage till your done. Resistors to get the job done will be about 5 for a dollar. That would be safer than trying to glue the needle with the sender in boiling oil.
Go slow with the sender heating so it has time to heat up inside. It takes it a second to catch up with the liquid temps.

It wont take much glue at all. "Gorrilla" brand super glue should hold it forever. You'll want just a smear in the needle hole. Then hold the guage face down while you stick the needle on and the glue dries. You DONT want any glue going back up the post.

Use a battery and wire up hot and ground to the guage. Put the right resistor/s in the send wire back to battery ground and stick the needle on.

Tested readings on the sending unit may be more accurate than published info.
Heating the oil to a certain temp and then lowering the sender in will probably work best. Just start out low and work your way up.


BE CAREFUL!!!!!!!
Any questions we'll be here.
If I had your parts I'd be more than glad to do it for you.
I believe you can handle it though.

Alright, ready to do the last step in the process here. Just want another view. Refer back to post #6, terminal 1 to ground, terminal 2 to +12v, terminal 4 is going to go to ground with resistors for my different temp settings (I'll post my findings when I'm done and maybe they'll want to make this a sticky). Should Terminal 3 have +12v applied too for the test?

["QUICK-SILVER"]

"Should Terminal 3 have +12v applied too for the test?"
_____________

I wouldn't think so. Battery (+) on whichever stud gets power from the switch with it turned on should be all it needs power wise.

Don't know about yours but later model guages (70 up F body) only use/need two post to work, hot and sender. They do have different sending units though from yours. Different part number anyway.

I need to find me a 4 post to have here for testing purposes. It's nice to have parts in hand when you're trying to help someone and can't see what they're seeing.
---------------------------------------------------
Also on the 70 up F body guage, it's got 5 marks, first is 100°, middle is 220°, and last is 260°. The two inbetween lines aren't labled. So there's a big difference in degree readings between the top half and bottom half of the guage. 120 from start to middle and only 40 from middle to end.

The reason I posted this number difference/spread on the guage was so you'ld have some idea how far off the needle could be if you randomly stuck it on.

Just saying the readings you get on the sender will be important before you hard wire it with a resistor and glue the needle on.

[torqhead]

Originally Posted by "QUICK-SILVER"

"Should Terminal 3 have +12v applied too for the test?"
_____________

I wouldn't think so. Battery (+) on whichever stud gets power from the switch with it turned on should be all it needs power wise.

Don't know about yours but later model guages (70 up F body) only use/need two post to work, hot and sender. They do have different sending units though from yours. Different part number anyway.

I need to find me a 4 post to have here for testing purposes. It's nice to have parts in hand when you're trying to help someone and can't see what they're seeing.
---------------------------------------------------
Also on the 70 up F body guage, it's got 5 marks, first is 100°, middle is 220°, and last is 260°. The two inbetween lines aren't labled. So there's a big difference in degree readings between the top half and bottom half of the guage. 120 from start to middle and only 40 from middle to end.

The reason I posted this number difference/spread on the guage was so you'ld have some idea how far off the needle could be if you randomly stuck it on.

Just saying the readings you get on the sender will be important before you hard wire it with a resistor and glue the needle on.

Yeah, the 69 starts at 100 and ends with 250, no indication for the middle although I'm assuming it may be around 200 just from the fact when it was working and I had a 180 thermostat in, it would hover just below the half way mark. So I've got several readings through two test I performed with the sender. Stay tuned and I'll post the results and pics for a 4 post version.

[torqhead]

Thanks to Quick Silver round tabling this with me for awhile I've now got my temp gauge working. In my case the needle just plain fell off. But for anyone that needs information how to test, etc. their gauge here's what I did. Attached in the pic I'm providing is a snapshot of the back of the gauge.

Picture attached has leads numbered 1-4.

1 is shorted to ground.
2 gets +12v with ignition on.
3 has power with ignition on and will vary depending on position of gauge ( I found about 6 volts when the engine was cold and closer to 10 volts when gauge was reading approx. 190 degrees.)
4 is the lead that comes from the engine bay (green wire)

The test can be performed with the gauges in the car or out. To test your gauge, go to Radio Shack and buy a pack of 100 Ohm resistors (1/2 watt is fine), they cost 99 cents.

If the gauges are in the car just take a voltmeter and ensure you have +12v on number 2. Use your ohm meter, easier to use if you have the option on your meter that provides a tone when a dead short is detected. Check to see if 1 and touching something metal is shorted (validating a good ground). Also disconnect the green wire under the hood going to the sending unit. Then take your meter and connect to the wire you just disconnected in the engine bay and test between it and ground of the car like the engine (this should show open, no connection, no tone).

Take two of the resistors and tie one of each end together (twisting them together is sufficient, but soldering is better) this makes a 200 ohm resistor. Have someone go into the car, turn the ignition switch on and watch the temp gauge. You can take one end of the resistors and connect it/hold it to the green wire under the hood. The other end touch ground (engine is fine). Don't worry, this will not electrocute you. The gauge should immediately move to a position just under half way (this probably will be the same for cars anywhere between 68-74 on most models. Can't imagine they would be drastically different. 200 ohms on my gauge sending unit was about 160 degrees. If you want to test for 180 degrees you need about 185 ohms.

As I said in my case the needle fell off, so I tested the sending unit in hot boiling water, I did multiple test for consistent results and found the readings during cool down of the water from 205 degrees down were more consistent and these were the values I worked off to mount the needle in the right place. I went with 5 readings:

Degrees Ohms
140 270
160 200
190 160
200 135
205 120

I first put the 160 ohm resistance in the wiring that I set up outside of the car (just used a battery charger for my 12 v source at 10 amp charge. Had it all powered up so the gauge would be turned in the right position. I pushed the needle down on the stem a little before 1/2 way on the gauge. Then I changed the resistor to the 200 ohms, needle immediately went lower, then 270, needle almost was at the 1/4 mark, then changed to the 135 ohm, needle jump to just barely below the half mark and then i put in the 120 ohms, needle landed right on the half way line. Once I validated all of that, I went back to the 200 ohm, removed the needle and then mounted the needle permanently halfway between the 1/4 mark and 1/2 gauge mark. Verified my test again to ensure all positions landed in the same spots as the test before.

Done deal.... I took apart the gauge cluster and repainted the inside with a light blue similar to factory color since mine was starting to rust a little. Hoping this makes my dash lights a little brighter since I'm getting old and can't see as well... lol

Like I said, hope this helps someone in the future. If you have any questions I'd be glad to help. Thanks again to Quick Silver and hanging with me on this one. What's that guys name anyway...

Now I'm off to reassemble everything including the dash Dave