Gauge & sender compatability research (1 Viewer)

[bsmith123]

Since there are so many mods and swaps the issue of gauge/sender compatibility often comes up

Do you know the specs for a sender or gauge? If so post it up



Also the ammeter is an issue, I was researching if it was possible to mod an ammeter from an internal shunt to an external one? Still working on that. If anyone has an old ammeter that is not working they are willing to part with let me know cause I'd like to tear one down and experiment with it

I am thinking it may also be possible with resistance to double the range in the ammeter and turn 0-30 to 0-60 or even 0-120 as long as it is no longer wired in series and all of the current does not need to flow through it

In the following post there is some info from Stewart Warner on checking the fuel sender range which I thought was useful --just check the ohms and move the float with a wire--pretty simple!
At least with that you can compare senders.

 

[bsmith123]

Checking the tank sender, mixing senders, temp gauges

REF:
Stewart Warner FAQ's

How do I determine the ohms of my current fuel sender?

ifyou're not sure of the fuel tanks impedance, determine it's' resistance by following this method:

Disconnect the fuel tank sender from the gauge.

Connect an ohmmeter across the fuel tank sender. Connect the meters positive lead on the fuel tank sender's output and the connect the ground lead to the fuel tank sender's flange.

Manipulate the position of the float arm with a piece of wire or some other device so that you can position the float arm in the full and empty locations.

The range for Stewart Warner fuel senders are: Empty - 220 to 260 ohms; 1/2 tank - 80 to 120 ohms; full tank - 20 to 50 ohms. This is normally noted as 240 ohms at empty and 33 ohms at full.

GMAC fuel tank sender will read in the opposite direction. At empty, it will read zero ohms and at full it will read 90 ohms.

Ford/Chrysler fuel tank sender will read zero ohms at empty and 73 ohms at full.

Can I mix Stewart Warner gauges with senders of another make, or vice versa?

Generally no. If mixing is intended, electrical characteristics must be determined in advance of installation to insure compatibility.

Pressure Systems:

Both gauge and sender should have the same impedance to be a perfect match. For best overall performance, we recommend that you use Stewart Warner gauges and senders together.

Other manufacturers will specify that their gauges work with Stewart Warner senders. We don't sanction the mixing and matching but in some cases, their gauges will match our pressure senders.

A 240 ohm gauge should be matched with a 240 ohm sender.

Fuel Level System:

Fuel systems are quite the same as pressure systems. Gauge and fuel sender must have the same impedance to function correctly and both should be at the same ground potential. For best performance, Stewart Warner suggests that you purchase our matching gauge and sender combination.

Water Temp System:

This is the most difficult system to match. Most temp gauges are designed to work with one particular sender. Each sender has an electrical element with its' own characteristics. It is very difficult to find another manufacturer whose gauge dial angles will match the senders resistance/temperature curve.

When trying to match temp gauges and senders of different manufacturers, the most critical point on the gauge is the thermostat temperance. If this combination produces a reading that is with-in 5º F of the thermostat temperature, and it stabilizes there, then this combination can be used until you can purchase the gauge and sender combination that was designed to work together.

For selecting a temperature sender, what information should I have before contacting a distributor or sales rep?

What temperature range do you need (eg: 100-240°F)

What thread size do you need (1/4" is standard and a universal kit is available containing adapters for 1/4", 3/8" and 1/2" pipe threads, metric adapters are also available)

If you wish to try to match an existing gauge, what is the resistance range (ohms) of the current gauge (see question on mixing Stewart Warner and non-Stewart Warner instruments and senders). Your distributor or sales rep can assist you with this if you have the gauge brand and part number

Do you need to run two gauges with one sender

 

[bsmith123]

more info

differences between the instrument clusters
https://forum.ih8mud.com/40-55-series-tech/281457-gauge-cluster-interchange.html

2 temps senders? One is for emissions
https://forum.ih8mud.com/40-55-series-tech/282866-temperature-sending-unit.html

 

[bsmith123]

external shunt

This is an external shunt, the 40 has an internal shunt

I am thinking that it may be possible to add an external shunt resistor to extend the range of the 40s meter.

seems like zero and max would work but I am not sure of the range in between

ir would it be possible to remove the 40s shunt and replace it with an external one?

 

[Downey]

Mr. Smith, I've lost track of how many times I've posted all the specs on the Toyota fuel sender. Since we already know precisely what ohms they work on, we don't have to go through the Stewart Warner proceedure.:
(a) Up to 9/72 is 100 ohms empty, 3 ohms full, but with a 7 volt drop built into the Toyota sender.
(b) From 9/72 is 120 ohms empty, 17 ohms full, full 12 volt operation.
While we do build digital senders in these values, there is a problem trying to combine use of the 9/72-older sender in stock front tank with a sender of the same value in a rear aux. tank. For the long explanation, PM me!!

 

[bsmith123]

fuel

Jim,

thanks for those specs I guess my search on gauges was too general. Im Ok on how things work I was just looking for specs. Hmm I am thinking you couldnt wire two senders in series to one gauge since they depend on resistance-I'll PM for the whole story thanks!

I think the SW procedure is good in any case because of all the combinations people can wind up with OEM and Not OEM and mixed

Well that takes care of the fuel sender. In general terms I suppose with a variable resistor I could check any gauge's range to match it to a sender but I don't have all of them so I am trying to gather some info here if it is already available

I am hoping to get specs for all the sensors and senders IE water temp, Oil pressure, the emissions temp sender etc


The other thing I am working on is to see if I can modify the OEM ammeter to an external shunt in its original range and in an increased range say 0-20, 0-60, 0-120.

 

[ken_79-fj40]

Normally I wouldn't bump a 5 year old thread but this is exactly what I'm trying to figure out. The 68 I'm working on has a later cluster in it. Like 70-ish. No turn signals in it and screw terminals for the gauges. Nothing works but the speedo. So a set of mechanical gauges took care of oil/volts/temp but it's got no gas gauge. Sender seems to work and I was seeing about 70 ohms full and nothing empty. Which would jive with a ford setup according to the above but I believe it's a stock sender. History of the truck is a complete unknown though.

Checked it again and think the sender is toast too. The resistance does seem to vary but it's completely random. Earlier I had 65-70 full and nothing empty. Checked it again and got 1600 empty and nothing full.

 

[Solace in Solitude]

Normally I wouldn't bump a 5 year old thread but this is exactly what I'm trying to figure out. The 68 I'm working on has a later cluster in it. Like 70-ish. No turn signals in it and screw terminals for the gauges. Nothing works but the speedo. So a set of mechanical gauges took care of oil/volts/temp but it's got no gas gauge. Sender seems to work and I was seeing about 70 ohms full and nothing empty. Which would jive with a ford setup according to the above but I believe it's a stock sender. History of the truck is a complete unknown though.

Checked it again and think the sender is toast too. The resistance does seem to vary but it's completely random. Earlier I had 65-70 full and nothing empty. Checked it again and got 1600 empty and nothing full.

Ken,

Search "Gauges" Posted by member: bj40green

Rudi has a ton of related info on MUD

HTH