4AD petrol gauge sending unit Needed

[Grantbradley]

after finally finding a petrol gauge i now find my sending unit burnt out. so anyone know of one or

what might work?

[cev196]

My understanding of these units is that they are a coil of wire with a contact slider, if the wire is burnt out sourcing some replacement wire and rewinding by hand would be a possible solution. In the past I have successfully rewound a scalextrix motor (and it worked after!).
What does the inside look like?

[Mark Thompson]

I believe that the MGT series uses a similar unit.
Mark T

[Phillip]

Hey Grant,

PM me. I might have one in stock.

Cheers,
Phillip

[Grantbradley]

After some searching and luck...i have determined that the sender unit from a 1956 Mortis Minor is a direct bolt in with correct 0 to 90 ohms range.
my Morris friend says that the sender is the same for 1948 thru 63 Morris Minors.
Grant

[tvdwerf]

You are right, and I did not noticed....
My '51 Morris is parked next to the 4A with the fuel sender out of the tank.
Because the one from the morris has his problems to, I was preparing to order a new one here:
https://www.morrisminorspares.com/fuel- ... es-p830603

[ColinB]

Just a question - my '37 Coupe needs a 0 to 30 ohm sender which seems impossible to find. As I'm really only interested in whether I'm running out of fuel would a 0 to 90 ohm sender work to that extent??

[jeans_old_man]

The needle would read FULL until the tank had less than 2 gallons in it. However, this could be improved by fitting a fixed resistor across the sender output. I have not tested this but I calculate a 47 ohm resistor would do the job. It will have to be a substantial one - rated at 2 watts or above. The accuracy is further improved if the float can be arranged to be at the empty position when there is (say) 1/2 gallon left in the tank.

[ColinB]

Thanks Brian - I knew you would have the answer! Sounds like an option if my non-functioning sender can't be repaired. I think I could also bend the float arm so it stopped on a full tank well before the 90 ohm level while still giving me decent empty reading.

I must get the Light Six's seats repaired and off to the trimmers but after that I'll have a go at removing the Nine's tank to have a look. I need to overhaul the fuel delivery anyway as the copper feed is loose and wobbles about, rubbing against the suspension which is just asking for trouble.

[jeans_old_man]

If you can arrange the float arm to only travel 2/3 of maximum - presumably by having a long arm - you could use a 68 ohm resistor and get an even more linear output. Don't forget, though, that the tank has baffles in it that may preclude the use of a long arm. This is useful stuff. There must be plenty of 90 ohm (BMC?) senders around.

Alternatively, buy a universal sender and matching gauge from the internet and print off a dial and change the bezel if required.

[ColinB]

Thanks Brian, I'm really grateful for your technical knowledge!

[Peter McKercher]

Just a question - my '37 Coupe needs a 0 to 30 ohm sender which seems impossible to find. As I'm really only interested in whether I'm running out of fuel would a 0 to 90 ohm sender work to that extent??

Here's a 0-30 ohm option for you Colin. I sourced it for a friend. It required redrilling the holes on the sender mounting flange, but otherwise works perfectly.
https://www.tanksinc.com/index.cfm/page ... prd276.htm

[ColinB]

Thanks Peter - that looks like a good option. Its also really helpful to know the cars it fitted as I can probably find one in the UK if I search under American car parts.