Re: 22nd, 23rd Series Fuel Sender

Posted by HH56 On 2015/10/20 14:23:13

You are right to be skeptical. That appears to be a straight resistance sender and while 48-50 gauges were bimetal they also used bimetal heater type senders which was basically an on and off operation. Sender heater in series with the gauge heater worked a bimetal strip in the sender which when bent enough opened a contact. Opening the sender contact broke the circuit to both heaters. That cooled the heaters and strip and contact closed again. The duration of the on vs off cycle time was determined by how much pressure the float applied to the bimetal strip. More on time equaled more heater action at the gauge and a higher gauge reading but since the gauge bimetal is slightly slower response than the sender the needle didn't change much during the off time.

The later years --51 on -- that ebay sender is supposed to fit used straight resistance senders of the Ford and Chrysler range of 10-73 ohms.

Having said that, there is a poster at the PAC site who did some experimenting on his 49 and appears to have determined a 0 to 30 ohm resistance type sender will work the gauge. What I don't know or remember hearing with any followup report is if there are any issues and whether he has his car on the road to see if all is satisfactory. Until proven otherwise, I am a bit concerned a constant voltage vs the on/off the gauge was supposed to be getting might be detrimental to the heater in the gauge or, since the gauge heater never cycles off to cool might result in a false and higher reading than actual after a lengthy period of being on.

If you want to read thru his posts and see if his sender is something you are interested in trying here is the link.http://www.packardclub.org/forum/viewtopic.php?f=8&t=2302&p=10281&hilit=fuel+sender#p10230 If you do try it would be good to get another trial to see how it works. The original senders are long obsolete and expensive to buy or repair. I believe that in addition to Classic Instruments as he used there are universal 0-30 ohm senders available just like the ebay item you show.

If someone made a 0 to 100 ohm universal sender for obsolete S-W gauges for Packards earlier than 48 that would be really nice. The GM 0 to 90 senders doesn't quite work on those cars.