‘72 Dart - Road Race Resto
Fuel Tank Modification
Despite my best efforts to retain the factory fuel tank mounting, the coil-over mounts crept into the tank's location just enough to necessitate either a trunk-mounted fuel cell or modifications to my OE-style tank.
I elected to modify the OE tank over the cell for a few reasons. Fuel cell cost was the primary driver followed by keeping weight down low and simplicity. While a fuel cell install isn't necessarily a "complicated" modification, it required drilling additional holes into the trunk and more plumbing/fittings than the OE setup, where all that was needed was a long piece of fuel hose to join the tank to the factory hard-line.
Process
Before doing any tank modification, the tank needed to be drained or the remaining fuel. To remove the vapors, the tank was rinsed twice, drained, and left outside for a day to dry.
To clear the coil-over mounts a roughly 4-inch strip was cut out between the front face of the tank and the spare tire well contour. Stitched welding proved to be the best approach, as trying to lay a bead on material as thin as the tank tended to result in a blowout. In between bouts of stitching the tank, I hammered out the gaps between the two pieces to tighten them up for easier welding.
Once welded fully, a leak test revealed a fair amount of pinholes and seeping welds, so the tank was drained against and I did what I could to stop the leaks. A second leak test showed an improvement but leaks were still present. Rather than chasing leaks, I lined the tank using Red-Kote, which did the trick.
With 4 inches removed from the tank, the factory tank straps were too long to use, so I simply folded them over at one end, copied the cutout they originally used to slot into the frame and everything snugged right up into place.
Closing Thoughts
If i were to do something akin to this again, I would TIG it, as I prefer the greater control it gives you for heat management and feel I would've produced less leaky welds. However, this was my first substantial experience welding thin material with MIG, so the fact I got it done at all and it was seal-able with an application of Red-Kote is good enough for me for now.
All in this project cost about $30 for the tank sealant and was done with a cut-off wheel on an angle grinder and a MIG welder. The fuel-cells I considered averaged $200, and the project price would've continued to creep up accounting for fittings and making sure it was done right. Even though this project took me several days to complete, I feel the cost savings and—admittedly frustrating—experience working with thin sheet metal well worth it.
This project was the last big one holding up driving the Dart. After pulling the motor back in March for a rebuild, the work on it snowballed in a such a manner where it had been on a lift or unable to move under its own power. Last picture is after its first drive in 7 months.
Fuel Tank Modification
Despite my best efforts to retain the factory fuel tank mounting, the coil-over mounts crept into the tank's location just enough to necessitate either a trunk-mounted fuel cell or modifications to my OE-style tank.
I elected to modify the OE tank over the cell for a few reasons. Fuel cell cost was the primary driver followed by keeping weight down low and simplicity. While a fuel cell install isn't necessarily a "complicated" modification, it required drilling additional holes into the trunk and more plumbing/fittings than the OE setup, where all that was needed was a long piece of fuel hose to join the tank to the factory hard-line.
Process
Before doing any tank modification, the tank needed to be drained or the remaining fuel. To remove the vapors, the tank was rinsed twice, drained, and left outside for a day to dry.
To clear the coil-over mounts a roughly 4-inch strip was cut out between the front face of the tank and the spare tire well contour. Stitched welding proved to be the best approach, as trying to lay a bead on material as thin as the tank tended to result in a blowout. In between bouts of stitching the tank, I hammered out the gaps between the two pieces to tighten them up for easier welding.
Once welded fully, a leak test revealed a fair amount of pinholes and seeping welds, so the tank was drained against and I did what I could to stop the leaks. A second leak test showed an improvement but leaks were still present. Rather than chasing leaks, I lined the tank using Red-Kote, which did the trick.
With 4 inches removed from the tank, the factory tank straps were too long to use, so I simply folded them over at one end, copied the cutout they originally used to slot into the frame and everything snugged right up into place.
Closing Thoughts
If i were to do something akin to this again, I would TIG it, as I prefer the greater control it gives you for heat management and feel I would've produced less leaky welds. However, this was my first substantial experience welding thin material with MIG, so the fact I got it done at all and it was seal-able with an application of Red-Kote is good enough for me for now.
All in this project cost about $30 for the tank sealant and was done with a cut-off wheel on an angle grinder and a MIG welder. The fuel-cells I considered averaged $200, and the project price would've continued to creep up accounting for fittings and making sure it was done right. Even though this project took me several days to complete, I feel the cost savings and—admittedly frustrating—experience working with thin sheet metal well worth it.
This project was the last big one holding up driving the Dart. After pulling the motor back in March for a rebuild, the work on it snowballed in a such a manner where it had been on a lift or unable to move under its own power. Last picture is after its first drive in 7 months.