Fuel tank replacement/upgrade (1947 DeSoto Custom Sedan)

[Racer-X-]

 

This is a progression  from my previous thread at

 

So we found a replacement tank from Tanks Inc that was already prepped for our EFI pump, and it was in stock at Summit in McDonnough GA (about 90 miles away). So I spent my Sunday fighting Atlanta traffic to go get it, and started test fitting yesterday. I'm going to need to do some mods to the tank mount brackets/straps.

 

 

This pic shows the front part of the existing bracket for the old tank.  Note that the curve doesn't match the new tank at all.  I don't like the way this fits.  I'll probably be cutting off the curved/contoured part of these brakcets.  Here's the back  of that same bracket.

 

Another issue is, while the new tank has been factory prepared for the EFI fuel pump (so it should fit perfectly and not leak), the hole for that pump is in a different location than we had it before.  Rather than cut another hole in the trunk floor, I'm considering putting some 1-1/2" or 2" square stock between the tank and the trunk floor and running the fuel lines below the trunk floor in the space that would create above the tank.  That would allow me to patch up the trunk floor and keep all the fuel lines and wiring out of the trunk and away from potential damage.

 

Any input or ideas about this is welcome. 

[LeRoy]

7 hours ago, Racer-X- said:

 

This is a progression  from my previous thread at

 

So we found a replacement tank from Tanks Inc that was already prepped for our EFI pump, and it was in stock at Summit in McDonnough GA (about 90 miles away). So I spent my Sunday fighting Atlanta traffic to go get it, and started test fitting yesterday. I'm going to need to do some mods to the tank mount brackets/straps.

 

 

This pic shows the front part of the existing bracket for the old tank.  Note that the curve doesn't match the new tank at all.  I don't like the way this fits.  I'll probably be cutting off the curved/contoured part of these brakcets.  Here's the back  of that same bracket.

 

Another issue is, while the new tank has been factory prepared for the EFI fuel pump (so it should fit perfectly and not leak), the hole for that pump is in a different location than we had it before.  Rather than cut another hole in the trunk floor, I'm considering putting some 1-1/2" or 2" square stock between the tank and the trunk floor and running the fuel lines below the trunk floor in the space that would create above the tank.  That would allow me to patch up the trunk floor and keep all the fuel lines and wiring out of the trunk and away from potential damage.

 

Any input or ideas about this is welcome. 

I hope you have better luck than I did with my new tank, it leaked at all 3 possible locations. So I've had it off and brazed it up 3 times. I hate getting flame on used gas tanks.

[Dan Hiebert]

That sounds like a pretty good solution to not having the exact fit.  If I were going that route, I'd make it so the tank would be relatively easy to drop again since you won't have access to it from the trunk floor for future work.  No different than modern vehicles where you have to remove the tank to do any work on it.

[Plymouthy Adams]

I have the original tank in my vehicle but did make a cradle just the same for install.  Reason for the cradle was to relocate the tank to the center of the car body utilizing original mount holes thus changing the offset so I could install dual exhaust.  Being a business coupe and flat floor, this was easily done.  As for the cradle...this may or may not give you an idea of what it may need.

 

 

 

Edited October 26, 2022 by Plymouthy Adams

[Racer-X-]

44 minutes ago, Dan Hiebert said:

That sounds like a pretty good solution to not having the exact fit.  If I were going that route, I'd make it so the tank would be relatively easy to drop again since you won't have access to it from the trunk floor for future work.  No different than modern vehicles where you have to remove the tank to do any work on it.

 

Yes, the plan is to make it as accessible as possible.  I'm still up in the air about cutting an access hatch.   One that would have a cover. 

 

19 minutes ago, Plymouthy Adams said:

 

That looks great.  If only our muffler guy ("Bubba's exhust and brakes") could've done that we wouldn't have had some of these leak issues. 

 

I'll try to get pix of my finished setup.  The deadline for this is Friday.  I have some 1/8" solid neoprene straps/tape coming in to line the tank straps and brackets with.  Our old rubber strips are not reusable.  The left side is just some goo I scraped off that was all that was left after getting soaked in gasoline.

[Plymouthy Adams]

I cut the extra hole as aligned with the new service location for the sender.  The original cover is in place and the wiring routes as normal there but the new hole cover is merely a 4 x 4 electrical handy-box cover with the preformed (raised) 3 inch opening for large outlets that I then welded a section of a metal over to enclose it.  The raised section of the handy-box cover provides sufficient room for the electrical terminals.  Just a quick means to cover the access without a whole lot of fabrication by using a ready made item.  Will be covered by carpet so no one is the wiser.   Might work for you also.

[LeRoy]

On 10/26/2022 at 9:43 AM, Plymouthy Adams said:

I cut the extra hole as aligned with the.......

Where is the spare on a business coupe? 

I have trunk envy, mine is covered with thick tar like coating I'm slowly chiping out. I got about a third of it cleaned up yesterday.

Edited October 28, 2022 by LeRoy

[Plymouthy Adams]

The spare is in a curtained compartment behind the driver...there is a locking compartment behind the passenger.

Edited October 28, 2022 by Plymouthy Adams