Fit old style fuel sense float arm to new

[krudo]

hey guys, anyone does this?

Here are the two next to each other. Old style much longer. Getting full tank reading from new one at 1/3 tank. Am I right in thinking the way to go about this is to lengthen / swap arms?

 

[krudo]

Forgot to mention. Have new style tank (old fuel sender head doesn't fit) with old 67 wire/dash.

 

[Solace in Solitude]

I lengthened the OEM sender I use in my aux tank, by using two roll pins (Lowes) and a length of wire clothes hanger.

Very easy job.

 

[Cruiser Corps]

According to my knowledge, the early style sender (58-9/72), your old / longer one, has a resistance range of 3 Ohms Full, 110 Ohms Empty, and the voltage supply is supposed to be ~ 7V.

9/72 - 1978 ( your shorter / new one) would range from 17 Ohms Full, 120 Ohms Empty, and sees a full 12V power supply.

The newer sender won't work with an older gauge, and vice-versa. Unless you've swapped the gauge and power supply, then you should be fine. But it sounds like you still have the original gauge.

- Josh

 

[krudo]

Yeah gauge is original. @pngunme how is the accuracy of the gauge after adjustment / lengthening of sender?

 

[Solace in Solitude]

It's as accurate as you make it. If you lengthen the arm to reach the bottom and there's no interference with the full sweep if the arm, it's still 17 ohms full and 120 empty.

But, as Josh said, you need the older sender... The newer 17F-120E, with 12v will not work with your earlier gauge.

There's a company named Centroid Products, in FL... That manufacturers a different style sender ( CENTROID PRODUCTS - Computerized Tank Display - Electronic Senders - capacitive fuel gauges).

Call them and give them your specs (length, ohms range) and they'll build one for you. It don't recall the price, but it was very reasonable.

The one they built for my '78 would never work correctly and their customer service was great. But, we spent so much time (they sent me two or three senders) that they refunded everything and gave up.

But, I don't know of anyone besides me who couldn't get it to work... I ended up buying a second OEM and lengthening it.

@Downey has used and recommended Centroid for years ... He can give you more info, if you need it.

Or you can install a second fuel gauge for your aux tank.

Good luck!!

 

[krudo]

So I either get a new gauge or get a custom sender built basically are my options. Because the old style sender doesn't fit in the new style tank anyway.

Thanks guys! @pngunme I'll probably go the custom sender route. Sounds like a clean solution.

 

[Solace in Solitude]

Get input from @Downey first.

I have no experience with Centroid and early 40s... Just my failures with my '78.

I liked Centroid and their product a lot... But, my issues seemed to be related to the voltage at the gauge and they weren't able to make it work... Even after spending several hours on the phone with me, testing various readings.

As I said earlier, Jim (Downey) has a lot of experience with them.

BTW Its very simple to add a second gauge... If you aren't concerned with originality.

Good luck!!

 

[krudo]

Is the newer gauge a clean swap with the old one? Never worked with electrics.

 

[Solace in Solitude]

I don't know... You could go through Rudi's (@bj40green) great thread --> Clusters, Gauges, Speedo & Odo meters

... or, wait for Rudi to chime in...

 

[krudo]

Will check it out thanks!

 

[bj40green]

Here he is........
Old style (pre '73): Voltage from the gauge to the sender is 12V. The sender has a built in VR (Voltage Regulator), that's the bump on top of the sender. In other words.... the working voltage for the sender is 12V.
'73 and later....... The FUEL gauge has a built in VR and makes a 7V for itself and the TEMP circuit.
On other words the working voltage for the sender is 7V.
Long story short: Cluster and and senders are a set. You can't mix a 2nd gen cluster with 3rd gen senders.

Hth,

Rudi

 

[bj40green]

NOTE: Forget the ohm values for the pre '73 sender (83320-35020) in both pictures.
To check those numbers you have to open up the sender to get those.
The problem is that there is an internal VR (Voltage Regulator) in series and that VR gives you wrong values like "open circuit" and 34 ohm and no change when you move the arm/lever.

Rudi

 

[Downey]

I agree with Rudi's info above, BUT we always found it easier to just add an optional aftermarket fuel gauge on 8/72-older rigs. Joel (the engineer) at Centroid originally gave us the info that a 170/33 ohm sender could be used on the older 110/3 rigs to compensate for the 7 volt drop built into the system, BUT too many reports of that NOT actually working????? The 120/17 ohms units work perfectly on 9/72-newer rigs since they are a full 12V system.

 

[krudo]

I agree with Rudi's info above, BUT we always found it easier to just add an optional aftermarket fuel gauge on 8/72-older rigs. Joel (the engineer) at Centroid originally gave us the info that a 170/33 ohm sender could be used on the older 110/3 rigs to compensate for the 7 volt drop built into the system, BUT too many reports of that NOT actually working????? The 120/17 ohms units work perfectly on 9/72-newer rigs since they are a full 12V system.

Do you mean replace the old gauge with a new one or just add a newer gauge next to the cluster? I'd like to preserve the original cluster if i can

Sounds like I'll give Centroid a call

 

[Downey]

If it were me, I'd just install a 9/72-newer fuel gauge into my 8/72-older rig if I wanted to retsina the factory look, then use the Centeroid 120/17 sender (in fact into both tanks if I had the $$$ to do so).

 

[krudo]

Thanks. I'll have to price it all out and see what I can do. Where does one find the newer gauge? I've seen very few on ebay

Also if I install a newer gauge wouldn't the newer fuel sender work that came with the tank?

 

[Downey]

Thanks. I'll have to price it all out and see what I can do. Where does one find the newer gauge? I've seen very few on ebay

Also if I install a newer gauge wouldn't the newer fuel sender work that came with the tank?

Ask Rudi, I'm not sure if the 7 volt drop is built into the sender, the gauge, or the harness?????

 

[DSRTRDR]

when I got a new tank, we used the old sender again - had to adjust the hole size

 

[krudo]

when I got a new tank, we used the old sender again - had to adjust the hole size

Oh that's interesting