Universal Fuel Sender

Old Fogey UKOld Fogey UK Posts: 215Expert Adviser
The original fuel gauge / sender on my 1934 H8 have never worked at all.
I tried a cheap universal replacement sender I bought on eBay. It had an unspecified resistance. 
It sort of works - when I turn on the ignition, the gauge goes up to quarter full and then just stays there irrespective of how much fuel I put in.
So, I've bought another more expensive  universal sender. This one is adjustable to suit tank depth. It is 10-180 Ohms resistance, which I understand is correct for the gauge. It looks like the type sold for mid-30s Fords.
The only problem is that the instructions say it's to be used on a positive earth vehicle and my car is negative earth.
Will it work OK ?
If not, is there a modification I can do to make it work ?
Or have I just wasted my money (again !) ?

Comments

  • Ken U-TxKen U-Tx Posts: 3,772Senior Contributor
    As it is just a variable resistor, it shouldn't give a rat's patooty as to what polarity the ground is, unless it has some kind of electronics on it, which I doubt.
  • Ken U-TxKen U-Tx Posts: 3,772Senior Contributor
    The original sender on your car was a thermistor type, not a spiral wound & brush type variable  resistor type like the new ones being sold. In order for that sender to work accurately across the range and with the varying charge output of the generator, you need to put a 5.5 V constant voltage regulator in the line from ignition switch to gauge.
  • bob wardbob ward Posts: 1,094Senior Contributor
    I've bought a 10 to 180 ohm sender from Dakota Digital, its a variable resistor type and doesn't care about polarity. With a bit of tweaking of the sender stops to reduce the ohm range I can get it to operate my 35 H8 fuel gauge reasonably accurately, PM me for the ins and outs of the process.

    A word of warning, the gauge will burn out quickly if you hook it up to the 6V battery without the sender in the line. 

    https://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=112/mode=prod/prd112.htm
  • 40indianssgmailcom40indianssgmailcom Posts: 156Senior Contributor
    If using a constant voltage regulator with a 6 volt output, will that work with the stock gauge and sender?  .5 volt more does not seem as though it would harm anything and I think would make for a slightly faster gauge response if noticeable at all
  • tigermothtigermoth Posts: 411Expert Adviser
    If you have a core..a coupe of years ago John Wolfe told me than can restore the King-seeley senders. I had a few life events and have not sent the unit in yet.

    http://antiqueinstrument.com/index.php

    regards, Tom
  • Old Fogey UKOld Fogey UK Posts: 215Expert Adviser
    Thank you all for the advice. It looks like getting the thing to work is going to take more expertise than I have. So I will get an auto electrian to see if he can successfully install it - once the UK comes out of Coronavirus lockdown, of course !
    The original sender unit I took out of the tank looks nothing like the illustration in the Procedure Manual and I guess it was something Old Norris Smith put in when he owned the car as a lash-up to try to get the gauge working. I think it's probably a waste of time having it rebuilt as there's no guarantee it'll work afterwards.
  • Old Fogey UKOld Fogey UK Posts: 215Expert Adviser
    Bob - I have just looked at the link to that Dakota Digital sender and it looks identical to the one I've bought. A good sign, perhaps ?
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