Recently, while installing a one-way fuel check valve to keep fuel from going back into the gas tank after the car sits for a few weeks, I noticed that the AC glass bowl fuel filter at the carburetor had what looked like coffee grounds in the bottom of it. This is one of my favorite carsa 1936 Packard 1401 Rumble Seat Coupe. Its a Senior car with the 320 CID, 9 main bearing straight 8. I have had the car twenty years and have always kept fresh non-ethanol gas with stabilizer in it, and have never had any gas problems. But when I removed the fuel bowl, there was a dark-looking powder in the bottom of the bowl. The last time I remembered seeing this on another car, it turned out to be rust!
The 36s gas tank had been off around 10 years earlier when I had the tank sending unit rebuilt by our friends at Bobs Speedometer*. Then we had inspected the inside of the tank and put on a clear filter at the tank, so now, before removing the tank again, I hoped for a miracle and cleaned out the glass bowl filter at the carburetor, then started the car. Within a minute, the bowl filled up with rust again. I shut the car off and checked the original glass bowl filter between the tank and the fuel pump. It was full of rust too! The tank would have to come off.
First, we disconnected the battery, jacked up the left and right sides of the car and put jack stands under the frame. We also put a floor jack under the tank. I always put an extra ground wire from a mounting bolt on the sending unit to the cars frame. This helps to keep the fuel gauge needle from bouncing around. I removed this next. The metal filler neck has a rubber hose to connect it to the tank, but the clamps are impossible to get to, so the tank must be lowered 2-3 inches to give access to the clamps to free the tank from the filler neck. The fuel line must be disconnected before the tank is fully lowered. If the tank is lowered and allowed to hang by the line, it will bend the metal fuel line, preventing fuel flow. The 36s tank mounting is unique. It mounts with two bolts in the rear and one bolt at the front instead of two straps with Tbolts like most vintage cars have. It is important to mark the way the sending unit goes in. The bolt pattern will allow it to go in several ways, but the float must go in pointing toward the right, or it will hang up inside the tank and not swing freely. With the tank off, I capped off the cars fuel line to keep anything from getting in it while the tank was off of the car. When we poured the tanks gas into a clean container, it was obvious that there was a lot of rust in the tank. The clear plastic filter at the tank was full of rust, too. I really dont know how the car was running.
When I ran a scope down into the tank, I could see that rust ran all across the bottom. After removing everything from the tank I took it to Chatt-Town Radiator*. It is owned by my longtime friend Danny Burnettethey still will rebuild gas tanks and radiators to original specs, which is very important to me. The tank would have to be put into a large boiling tank and boil until the rust loosened and came out. This usually takes three weeks. Danny said this happened because when a car sits, even with fresh gas with stabilizer, and the car doesnt move, the gas is stationary, it interacts with the metal and if you just keep 4-5 gallons of gas in the tank, condensation will form at the top of the tank and the rust will fall down into the gas. (Rust can also form on any surface in the tank.) So, another reason to drive our cars!
While the tank was away, I bought a new tank filter, made a new sender gasket, cut new hoses, bought a new tank hose from the tank to the filler neck. It was a 2straight rubber hose I bought by the foot from OReillys. Dont be tempted to use radiator hose for filler neck hose because gasoline will eat up the inside of the radiator hose over time.
When I picked the tank up, we made the decision not to seal it. The rust had come off and inside the tank looked clean and was down to the bare metal. There are two theories about using sealer in a tank: If the tank is clean, the car is driven regularly, and non-ethanol gas is used with a little Marvel Mystery Oil, the tank should stay clean with the exception of a little grit that the filters will pick up. If the tank is sealed and the car sits, many times the sealer will come off and when it does, it is almost impossible to clean the tank unless it is cut apart to get to the cracking sealer out.
When I got the tank back, the acid from the vat had etched the outside metal. Using a die grinder and wire wheel, I stripped the tank down to bare metal, then wiped it with PPGs Metal Etch, primed with Primer Sealer, and painted it with Cast. It looked great! I chasedout the sending units bolt holes in the tank and put everything back together.
Care must be taken installing the clear fuel filter at the tank to make sure the arrow on it points to the frontof the car. Before mounting the tank, a couple of us put one quart of Marvel Mystery Oil in, sloshed it around, then poured it into a clean container. It was clean (no rust). We poured the clean Marvel Mystery Oil back in, sloshing it around to coat the tanks clean metal.
We put the tank on the floor jack and positioned it to go back in. The fuel line had been disconnected from the filter at the fuel pump and the line was blown out and reconnected. Now all filters were replaced. We installed the tank in reverse order, poured five gallons of non-ethanol gas with stabilizer we bought from Bill Hirsch*, and turned on the key to check fuel gauge accuracy. It is a 25-gallon tank. We put in 5 gallons and the gauge registered 1/5 full, which is correct. I pushed the accelerator to the floor to set the choke and pushed the starter button and once the gas pumped up from the tank, the straight 8 started! So smooth! After a drive around the block, I let it run and checked the filters. No rust! And through all of this, somehow, the Stromberg EE-23 carburetor had been spared!
This is a great testimony for fitting a car with three filters1-one at the tank, 2-one before the fuel pump and 3-one at the carburetor. Job completed!
Next to the 36 in the garage is my 37 Packard Super 8. I bought this car in 1996 after decades of looking for a nice original. When the 36 and 37 Senior 8s sit side by side, they appear to be the same car and they do have the same engine and transmission, but underneath they are totally different. The 36 has a straight axle, mechanical brakes with a vacuum booster and continued Packards use of the Bijur lubrication system. The new 37 Super 8s had a new Safe-T-fleX independent front suspension and hydraulic brakes. The fuel systems are the same, except the gas tanks are different.
When I checked the fuel filters, they were the same as the 36, full of rust. The tank would have to come off. The 37s gas tank has the conventional 2 strap mounting. When the tank was removed, we looked in with a scope and the bottom had rust craters! Back to Chatt-Town. The tank had been coated over 20 years earlier and the coating was coming off. It took five weeks for Danny to get all of the coating and rust off. The inside was clean, but the bottom of the tank was still rough metal. We decided to coat the inside of this tank to provide a smooth, uniform surface for the gas to flow on. This time the coating was the way to go, because of how rough the inside of the tank was. I will not let the gas sit in the tank for long periods anymore. Fluids (gas) must move and not sit, corroding the metal surface it comes in contact with.
When deciding to seal or not to seal your tank, remember modern coatings are much better than my 37s that was put on 20+ years ago. AND coating a tank is a process. It takes time to clean, dry, prep, coat and dry (cure). You cant rush the process!
When installing the 37s tank, the same process as with the 36, there is a rubber collar that slips over the filler neck through the hole in the fender and settles on the top side of the fender. Sounds easy, but the tank and filler neck must be positioned just right to make the rubber grommet turn just right. Our rubber grommet was original and crumbled to pieces. Fortunately, they are still being made and can be bought from Steele Rubber*. We put a quart of marvel Mystery Oil in with five gallons of non-ethanol gas with stabilizer. With everything hooked up, the car was started. After a trip around the block, the filters were clear, the gas gauge was working, and I am now driving the car.
So much time and money for nothing more than not driving my cars. It is hard to drive collector cars in the winter, but I am starting them and moving them around, and lets all Keep em Driving!