Packard Forum Index » Post-War (1946-54)

If I were to have a really long response I'd probably compose it in a word processor program and then just cut and paste the response. Alternatively, you can compose a small portion, stop and hit "submit" every paragraph or so, and then "edit" to continue on. That way all you can loose is your last paragraph or thought.

This might help....
I use an email format to write any long or time consuming answers, if I stop it will go to "draft"...when I've completed the response I copy and paste it to the forum reply. Hope this helps.

In post 6 I mentioned hooking up a 22-23 gauge and sender to see what was happening with the bimetal type sender. Here is is.

I made notes on the scope photo but basically the gauge and sender heaters are in series and are somehow able to work with each other and know what the two separate pieces are doing. Haven't figured the "how that part works" exactly but I suspect it has to do with the specific resistance of the heaters and maybe the changing characteristics of resistance wire as it heats. The composition and characteristics of the bimetal is probably a factor too.

At any rate when the needle needs to go higher the contact closes to ground so the gauge heater gets a jolt and quickly moves to position. Once it reaches where it needs to go the sender contact starts pulsing to give it just enough heat to maintain position.

When the needle needs to fall the contact stays open longer letting the gauge cool and needle drop. Again, when it reaches the needed position the sender starts a maintaining pulse.

After seeing this action I don't see an ordinary timer circuit being able to duplicated the sender and not sure how accurate the straight resistance type will be. Granted the comparative high resistance of a conventional resistance sender will not provide as much quick heat as the 6v and ground of the bimetal sender. That may be what is enabling the resistance sender to work in maintaining the needle position short term.. The proof will be how accurate it is long term. Am anxious to hear more long term info on how Tinman_70s conversion works out and what value sender he settled on.

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thank you Howard,

great testchart and I think it is rather impossible to replace that with a resistor-type sender, you have to switch in an electronic that makes pulses (with a ballast resistor) to the instrument.

now we can claim, Packard wasn?t only the inventor of the steering wheel, the H-shifting sceeme, but also of digital car electronics!

Make that King-Seeley

fred? did you mean they invented it?

http://www.classicandexotic.com/store/c-85-king-seeley-hobson-fuel-gauge.aspx

If you have an Autolite generator that does not necessarily Autolite invented the generator. Likewise the King Seeley unit used in 48-50 was made by King Seeley but I have no idea who invented that type of gauge circuit. Seems someone had a better idea that only lasted 3 years

Elefant, If you don't have success in finding a replacement fuel sending unit for your 49 Packard I could send you a working used unit without the float for $30 plus any shipping. I have had success making a float using motorcycle carb floats or using two corks bolted together. I think any type of float could be adapted to the sending unit arm and could be adjusted to work. If interested send me a PM Good luck with your project. . packardtaximan

thank you! I send you a pm with my adress to check the shipping costs.

the float might be the minor problem, I thought about to use this with some soldering

https://www.rsb-parts.de/modell-1965/kraftstoffsystem/kraftstofftank-tankdeckel/3813/schwimmer-fuer-tankgeber-65-73


(link in german, it shows a 65 Mustang float sold seperately for a reasonable price)

Traditionally cork floats in fuel tank sensors were coated with shellac to keep them buoyant over time. This is no longer a good idea as, though gasoline itself is not a solvent for shellac, ethanol is. Brass floats to replace cork is preferred.