Gauges

[Stoffregen Motorsports]

9 hours ago, stevecar said:

If you have a full tank, the 320 sender should read around 90 ohms. You might want to pop out the sender and take a look at it. I have had good luck rebuilding the senders.

Often times the sender contacts just need cleaning. I do this with a spray on metal etch. Just spray it on the contacts, let it sit for a couple minutes and hose it off.

 

Other times, the contacts can be slightly worn through, and with a needle nose pliers you can bend the tab and give it some extra life.

[Rusty Dawg]

1 hour ago, Stoffregen Motorsports said:

Often times the sender contacts just need cleaning. I do this with a spray on metal etch. Just spray it on the contacts, let it sit for a couple minutes and hose it off.

 

Other times, the contacts can be slightly worn through, and with a needle nose pliers you can bend the tab and give it some extra life.

Well crap, I am confused as all get out now.  Do you feel that my reading is incorrect and thus I need to clean up the contacts to test again?

[thisismatt]

1 hour ago, Rusty Dawg said:

Well crap, I am confused as all get out now.  Do you feel that my reading is incorrect and thus I need to clean up the contacts to test again?

 

I would pull the sender and remove all doubt. It might not even be swinging it's full arc, thus hindering any attempt at a true full & true empty measurement...they can be pretty nasty.

[Rusty Dawg]

1 hour ago, thisismatt said:

 

I would pull the sender and remove all doubt. It might not even be swinging it's full arc, thus hindering any attempt at a true full & true empty measurement...they can be pretty nasty.

Good call.  I wanted to save a step, but I thought about doing exactly this to get a true answer.  I was actually also wondering if in fact there was an issue at the sending unit end, maybe it wasn't my wiring or gas gauge that was the issue and it actually does function.  That would be great to be able to use the original.

[Thomas Perkins]

On 12/8/2021 at 9:40 PM, Rusty Dawg said:

This is what is installed on my engine currently.  I thought everything on this Datsun J13 engine was metric, but I shouldn't have assumed.On my 720,I replaced both temp. sender and temp. sensor.On the sensor it came with a pig tail.I also rigged up the sender with a fitting.Also had to rig up a fitting on my oil pressure sending unit.I have to be careful when I remove the oil filter or I will pull the wires off.

 

[difrangia]

Pic of the inside of the original sender. If you're real careful, you can take some fine sandpaper and clean the side/sides of the coil that the contact finger makes contact with and carefully spring the finger away from the coil and brighten up it's contact surface. Check the ohms while you have it apart. Should be near 0-ohm when the float is fully down and about 90-ohm when it is fully up.

 

You can see the exploded coil laying out between the senders. This is the one that I rewound with new wire. I had to calculate the total length of the wire on the coil and acquire the correct diameter & resistance wire to do the job. The other pic is the core for the coil mounted in the tool that I built to re-hair and re-wind violin bows with. The tool is made from oak wood and uses part of an old mechanical drill brace for the winding mechanism. Lot of work, but I learned a lot in the process.

 

 

[Rusty Dawg]

6 minutes ago, difrangia said:

Pic of the inside of the original sender. If you're real careful, you can take some fine sandpaper and clean the side/sides of the coil that the contact finger makes contact with and carefully spring the finger away from the coil and brighten up it's contact surface. Check the ohms while you have it apart. Should be near 0-ohm when the float is fully down and about 90-ohm when it is fully up.

 

You can see the exploded coil laying out between the senders. This is the one that I rewound with new wire. I had to calculate the total length of the wire on the coil and acquire the correct diameter & resistance wire to do the job. The other pic is the core for the coil mounted in the tool that I built to re-hair and re-wind violin bows with. The tool is made from oak wood and uses part of an old mechanical drill brace for the winding mechanism. Lot of work, but I learned a lot in the process.

 

 

Holy smokes!!! That might be beyond my skill set if I have to rewire the unit. What's up with HP bullet in the photo?😁

[difrangia]

9mm Parabellum 'Critical Defense' round. I was probably using it to prop something up on a specific angle for another photo that I was taking at that time. I have numerous mechanical objects laying around on the workbenches that contain aesthetic value to me as inspiration when I work on projects. For me there is immense history in the parabellum round. For most people they just go BANG !! and tag something downrange. 

 

For my part, if it required rewinding the sender, I'd most likely go with the Classic Instruments unit that I posted up-thread. That's what is in my tank.

[Rusty Dawg]

1 hour ago, difrangia said:

9mm Parabellum 'Critical Defense' round. I was probably using it to prop something up on a specific angle for another photo that I was taking at that time. I have numerous mechanical objects laying around on the workbenches that contain aesthetic value to me as inspiration when I work on projects. For me there is immense history in the parabellum round. For most people they just go BANG !! and tag something downrange. 

 

For my part, if it required rewinding the sender, I'd most likely go with the Classic Instruments unit that I posted up-thread. That's what is in my tank.

Interesting!!  I went to remove the sending unit this PM, but I realized that since I just filled her up, fuel was starting to leak out so I'll have to take her for a cruise tomorrow to burn off some fuel.  Don't have to twist my arm to get me out with her anytime.  I will check the unit then, but I am intrigued by the Classic Instruments unit and reached out to them today.  FYI....The part part number you gave is no longer valid.  The new replacement part number is T-GML-06.

[difrangia]

Thanks for the new part # info. The 6 in the part # is for the length. They make senders in various lengths and ohm ranges to suit different gage systems. I see that your pickup is a 222. It probably uses the same sender as the 320 but I don't know that for sure. The bolt pattern in the tanks is an industry standard pattern and the sender only fits in one way as the pattern is not totally symmetrical. That's no problem with the Classic instruments unit due to it's design.

[Rusty Dawg]

Well I'll be a sum bitch!!  I pulled out the sending unit today to measure ohms at full and empty and at first it didn't hit me when I pulled it out, but upon putting in on my bench I notice the float arm was hanging down.  Problem was that the tank was full.  The arm was stuck in that position and I simply loosen it by moving it up and down.  I put a drop of lubricant where is rotates and it seems to work like brand new now.  I put it back in the tank and low and behold the original gauge which has read "empty" since I purchased it now reads "full".  Sorry to have wasted everyones time on this one.  Now on to the mechanical temp gauge.

 

 

I took readings while I had it out (just in case it ever goes out) and found that full shows 89.7 ohms and empty reads 00.5 ohms.

[thisismatt]

So, 90-0 and you need a new 9v 😄

[wayno]

Shit happens when they sit a long time, you may find other things happen also that do not make sense, like when you turn the ignition off the temp gauge moves all the way to the overheated position, but when you turn the ignition on it slowly drops to the cold position until it starts warming up.

[Rusty Dawg]

On 12/16/2021 at 11:12 AM, thisismatt said:

 

I would pull the sender and remove all doubt. It might not even be swinging it's full arc, thus hindering any attempt at a true full & true empty measurement...they can be pretty nasty.

In reading back, you were correct that it wasn't swinging it's full arc.  Hell, it wasn't swinging at all.

[thisismatt]

Hey, even a broken clock is right twice a day 

[Stoffregen Motorsports]

Nice work Roman!

[Rusty Dawg]

While being out of commission for a few days, I decided to tackle the installation of the mechanical temp gauge.  It was an easy process and I can now be confident of my engine's temp.

 

Thanks for the guidance.