The roadster stopped on the apron of the EPA testing facility. It had been coughing and missing for the past five miles, and full choke helped only after a stoplight. Popping the bonnet in front of the inspector was indiscreet, but it was necessary to determine that fuel starvation was the problem. A couple of the inspectors, bless their hearts, helped push the invalid off the entrance area. A few minutes with the metal gallon fuel can, some wire to hold the can in position, the use of the emergency pump near the carburetters and a quick re-routing job on the fuel feed line got us home. (If you have gone to the trouble of fitting an emergency pump and fuel pressure regulator, you can always run to the capacity of the emergency fuel tank - about 10 miles on a gallon can when you have to prime the carburetters and run on full choke a bit of the way; plan on stopping to siphon fuel from the main tank to the gallon can about every nine miles). In the end, the immediate problem that stopped the car was that rust from a bad fuel tank had totally plugged the fuel filter.
All this started while backing into the driveway when rear visibility was limited. Suffice it to say that the roadster selected a non-existent driveway five feet to the right of the correct path, and hung itself, on the fuel tank, no less. Armed with the latest in technology, a big wad of JB-Weld for fuel tanks, and a flashlight to eliminate the chance that an electric drop cord would touch off a fuel fire, we were amazed when the hole in the bottom of the tank had been caused by a nearly rusted through bottom. The rock had hit an area that was only dented. The real damage occurred when the force of hitting the rock resulted in strong flexing of the rust, and flexing is another thing that rust does not do well.
But wait - this tank was only four years old! And it had been given three coats of acrylic enamel before installation. Inspection revealed that the paint had held, but had pulled away from the fuel tank to make pockets that collected dirt and moisture.
We consulted with Barney Gaylord on his paint schedule and comments: The problem was that the factory probably had not cleaned the tank before priming, and the factory primer had let go of the tank before the acrylic enamel released its grip from the primer. We started with a new 12 gallon tank (this is the older, more economical size), and removed the factory primer by sand blasting (cover all the openings in the tank with two layers of tape and paper). Next, a coat of self-etching primer (about $15 a quart, made by SEM, Charlotte, NC, product number 39694) was brushed on. As long as you are using a brush, there is not nearly the health risk that is associated with the mist produced by a sprayer. Then followed two brushed coats of epoxy primer DP74 mixed with an equal volume of DP402 catalyst (about $45 total for a quart of each, made by PPG, Strongsville, OH). The final finish was epoxy appliance enamel from a spray can (about $7, from TruValue hardware). This stuff takes forever to dry, and some other top coat would be preferable.
Refitting a fuel tank is always a hassle, but the following hint from Kevin Bartlett worked perfectly: Run heavy iron wire (Ace Hardware, $4 per pound roll) between two adjacent tank flange holes on each side and the corresponding holes in the boot floor. Pull up on the wires, and the tank is pulled up to the proper position without jacking or stress.
And, when you do this at home, keep a fire extinguisher nearby, and replace the fuel filter when you replace the tank. And don't open the bonnet at the EPA testing facility.