FUEL PROBLEMS WHEN A CAR SITS, PART II
In last month's article, we covered some of the problems that develop from gas going bad in a car that sits for a period of time; problems ranging from shellacked fuel lines to stuck valves and locked up engines. The cars that we let sit with only a little gas in them developed rusty tanks and sticky sending units faster than the cars with full tanks. The less gas in the tank, the faster the shellacking took place. Many people when storing their cars will run them out of gas. If the tank is not sealed, it can immediately start rusting! As the gas runs out of the tank and the pickup tube is close to the bottom, it will pick up debris that will end up in the fuel pump, filter and maybe the carburetor. For storage, the best thing to do is to fill the tank and add gas stabilizer, then twice a month start the engine, letting it run through its heat cycle of at least 20 minutes' running time.
Once when working on a '54 Packard Panama that had sat for several years, we emptied out several cups of rusty scale from the tank. Of course, the pickup tube was clogged and had to be cleaned out. Also, our dash gauge wasn't working, so we weren't surprised to find a cracked brass float, which was easily soldered and put back into service.
On our '51 Packard Mayfair, we found silicone on the gasket at the sending unit-to-tank assembly. When the sending unit was put on, someone had loaded it up with silicone sealer that squeezed down into the tank when the sending unit was tightened down, which plugged up the pickup tube. We never use silicone, but sometimes use Permatex 2-B non-drying, lightly applying it to the tank side of the gasket with a finger, which gets just tacky enough to create a good seal to the tank.
Another safeguard against rust getting into your fuel lines is an inline fuel filter at the tank and an AC glass bowl filter at the carburetor. We have seen newly-rebuilt fuel pumps ruined by putting them on without thoroughly cleaning out the system.
After sitting for half a year, our '37 Packard Super 8's tank had to be removed to get rid of the old gas. Our gas gauge was stuck on half-full, so we weren't surprised to find a stuck sending unit. When we freed it up, we tested its accuracy by watching the dash gauge while the swing arm on the sender was moved up and down from the lowest to highest points. We discovered that at its lowest point, it showed 1/8 tank instead of empty. This was corrected by moving the float arm back one gear tooth, which allowed the gauge to read accurately. The '37 also had an auxiliary electric fuel pump at the tank (operated by a switch under the dash) to pump the gas to the engine when the car had been sitting for a while. This worked okay, but the downside to this is that it puts extra work on the engine's fuel pump, which has to pump gas from the tank through the auxiliary pump to the engine. Our system is a 4 lb. fuel pressure system. We have heard that using an auxiliary pump at the tank with lower pressure (approximately 2 lbs in our system) would not overwork the engine pump, but we decided to eliminate the tank pump altogether and just start the car normally. This works great!
As we mentioned last month, we always ground our fuel tanks from a mounting screw at the sending unit to the car frame. This helps to give a steady reading at the gauge and eliminates gauge needle "bounce".
Fuel problems can destroy a car's engine. The simple solution is to drive and enjoy our cars!
Next month we are going to put a rear main seal in a 401 Buick Riviera. Have a great month. Keep 'em driving!