Sending Unit

[chewiebarker]

If I swap to a 40 gallon fuel tank can I simply bend the arm from my 21 gal tank to make the float read 'full' for the new larger tank?

[67 Burb]

Reading "full" will not be the problem, because the sending unit will still be on the top of the tank. Is the height of the 40 gal tank the same as the 21 gal tank? If the 40 is taller (deeper), the float arm would have to be longer to move from bottom to top correctly. Bending it won't help. I'd be more concerned that the gauge be more accurate at "empty" than at "full".

It wouldn't be the first time I had to catch a ride to the next town carrying a gas can.

[tedfrk]

If you swap to a 40 gal tank why not just get that sending unit?

[chewiebarker]

Originally Posted by tedfrk

If you swap to a 40 gal tank why not just get that sending unit?

I am having trouble finding a unit for a 40 gallon tank that reads 90 ohm. They all seem to be 95 ohm. Also, I already have a new sending unit for a 21 gal tank and I am a cheap bastard! As you know, being on the east coast, I can't simply walk into a junk yard and find a 40 gallon tank from the early 80s (which had a 90 ohm sender, I think) - they don't exist.

[72MARIO]

A sending unit from a 73 up Suburban still reads 0-90ohm. I would just buy it. there pretty reasonable.

[chewiebarker]

Originally Posted by 72MARIO

A sending unit from a 73 up Suburban still reads 0-90ohm. I would just buy it. there pretty reasonable.

Thanks. I will see what I can find in those years. All I seem to find is a 95 ohm units - alhtough I was looking at mid 80s mostly.

Also, I am not finding that 73 up had 40 gallon tanks.

[LockDoc]

Originally Posted by chewiebarker

Thanks. I will see what I can find in those years. All I seem to find is a 95 ohm units - alhtough I was looking at mid 80s mostly.

Also, I am not finding that 73 up had 40 gallon tanks.

I bought a new Suburban in '73 and it had a 40 gal tank.

LockDoc

[chewiebarker]

Found one that references 40 gal tanks in that year. Thanks Mario.
http://lmctruck.com/icatalog/csb/full.aspx?Page=145

[72MARIO]

No problem. The 0-90 ohm is something I learned on this forum when building my old short box and installing a 20 gallon fuel cell. I think GM stuck with that type of gauge reading to 1991 for sure not sure past that year. I wish I could get a bigger tank in my 68 suburban easily.

[chewiebarker]

So....the original sending unit, on the 21 gal tank, has only one outlet. The 1973 sending unit on the 40 gal tank has 3 outlets. What are the other outlets for and what should I do with them? Just plug them?

Actually, RockAuto only has the 4 outlet ones. http://www.rockauto.com/catalog/more...328&cc=1294062

So, one must be a vent line, which shouldn't be blocked...what about others?

[Faster57]

I used a '73 tank & sending unit in my '71 and just plugged the 2 extra lines. you need one for fuel & one for vent

[chewiebarker]

Fantastic. Thanks!

[ranger danger]

In for the picture