I'm relatively new to Model Ts, but not to cars. It's time for some of us to park our Ts for the winter. If your T will be placed in an unheated structure, I would suggest that you drain the fuel tank and the fuel system. The gasoline of today in many states contains 10% Ethanol. Ethanol loves water. Water loves the inside of fuel tanks. My T was purchased from the estate of a man who died - the T sat for a couple of years in an unheated garage. It's performance has been poor, and it did not make it home under it's own power once. When I started draining the fuel system, the fuel just trickled out. The tank and strainer were totally contaminated by rusty crud. The tank will come out for cleaning in the spring.
I've never had to do it, but a tank-cleaning method I think is pretty ingenious is to jack up a rear tractor wheel, bungee the tank onto the wheel with some chain in it, and tumble. I suppose you'd want to adjust the tank position from time to time to be sure all of the inside gets the chain tumbled over it. Why chain and not rocks? Easier to get out.
John I had good luck cleaning by letting them dry out really well. Remove the tank and fittings from the tank.
If you have it boiled out or vatted it wont matter but if you use small gravel or some type of chain it will work really well.
How is that chain going to get past the baffles?
Or rocks for that matter. I've noticed myself, as John suggests, a good drying out can free a lot of stuff that's caked on the innards. Air pressure works well for freeing this junk too but you're back to those baffles. A long piece of 1/4" tubing on the spray nozzle helps.
Here is a link to how I cleaned mine. I didn't have any trouble getting the stones out.
I had a similar problem with my gas tank, and never had it off the car. I carried a bit of wire bent in a v so that I could run it up the drain of the sediment bulb through the bottom of the gas tank to get the crud flowing, after about two months and about twenty times doing this, I have only had to clean the drain once in the past 2,000 miles. I also use Belray 2 cycle oil in the gas an a regular basis, and it helps to keep the crud from sticking to the tank so it flushes out quicker. If the car was parked with gasohol in it for an extended time, then you probably have a build up of the grey powder that comes from spoiled gasohol, that is very hard to get rid of. The belief that the rust is caused by gasohol is not really easy to understand, as the alcohol absorbs any water that is in the tank and it is removed with the gasoline. It is impossible for gasohol to bring water into the tank as the gas tank should not allow water to pass through it. Even with a tank left in a rain storm with the cap off you would not have a problem with water, as a tank with 10% gasohol will absorb a volume equal to the alcohol before it will separate. I suspect you rust problems pre-dates the use of gasohol when the smallest bit of condensation would settle to the bottom of the tank where it would cause the rust.
Gustaf, Ethanol in gasoline attracts water but will not absorb it. Therefore the water separates and goes to the bottom of the tank. Isopropol alcohol will absorb water so it can be passed through the carb without damage and burn as part of the fuel. What I do not know is the BTU yield of that water/isopropol mix as compared with either gasoline or isopropol.
Sorry, it's spelled "ISOPROPYL". Its the same stuff that's in the Red bottle of Heet.
Kevin, Alcohol of any kind can not attract water unless it is already in the tank. It will stay mixed with the gasoline until it reaches 100 proof or lower, that means that it will not separate until the volume of water to enter the tank is equal to or more than the volume of alcohol in the gas. It is possible that you are buying gas from a disreputable seller who is already adding the water. I never waste money buying Heet, I just put a tankful of gasohol in each vehicle in the winter to clean any accumulated water from the tank.
I do not know where you came up with the notion that alcohol will not absorb water, every time I have ordered a mixed drink, the water stays mixed with the whiskey, heck all drinking alcohol is already 53% water.
Here is an EPA memo on the subject:
That is interesting, although the amount of water that gasohol will absorb is much lower that I thought, The FFA recommends using 10% water added to a measured volume of gasoline to test for alcohol, by adding the 10% water, you will get twice the volume of liquid separated from the gas if it contains alcohol than if it does not. It looks like gasohol will absorb far less water than I had thought, but it still remains a fact that the only way you can get too much water in the tank to get phase separation is to stick a garden hose in the tank.
Take the tank to a reputable Radiator Shop and have them boil it out in their Sodium Hydroxide tank. If the metal is good it will make it like new (my original came out awesome). If it is bad you will find out, and with that knowledge get another or do what you will.
Rebuild or replace the Sediment bulb & Valve.
Get new teflon lined fuel line.
Install a shutoff prior to the carburetor.
Rebuild or buy a rebuilt carburetor (Ahoy, Stan Howe).
Check your Manifold gaskets, do what is necessary.
If you do these things, you should be able to feel confident and safe with your fuel system.
My $0.02 contribution
Tumbling a tank to clean it can work really well. But even better than chain or rocks is a couple of pounds of drywall screws (length not critical).
They are incredibly sharp and very hard so they will reach even tight corners where rocks and chain won't reach.
Best practice is to then coat the tank with an epoxy sealer.
Gustav, Where you live in Idaho, you may not have to deal with the humidity that we do up here in the Northwoods of Northern WI. What happens is that cool gas in the tank is used by the engine and displaced by humid air as the vehicle is operated. It is more of a problem in the spring and fall. I think if you do a little more research, you'll find that there are different forms of alcohol and they behave differently in the presence of water. Lots of folks have turned to the alternative of filling up with non-oxygenated fuel. More costly alternative than filling up with regular, but it does seem to help. Any chemists out there want to weigh in on the issue?
I live in southern Idaho where the humidity sometimes gets in the upper 30s. I do not believe that enough air can enter the tank to deliver the amount of water needed to cause problems, especially if you are running gasohol. According to the EPA report, it would take 200 gallons of air at 100% humidity at 100 degrees to deliver enough moisture when the temperature dropped to 40 degrees to cause a problem in un oxygenated gas, now if gasohol is able to extract that moisture from the air, then you would not need to have the temperature drop, but you would either need a 200 gallon tank or only have less than a cup of gas in the tank.
40 years ago, I preferred gasohol, my vehicles ran better with it, but the new stuff give about 10% less performance, so I run gas with out alcohol. The difference is not the alcohol, it is the way they refine the gas. There are different alcohols, that is true, but most gasohol is methanol, produced from grains and sugar, and all alcohols will suspend more water than gasoline alone, and that means you would need less than a cup of gas in a 10 gallon tank to have a problem, other than running out of gas.
Gustav, Only 30%? That's considered bone-dry around here. I just checked the National Weather Service for our area. At a crisp, clear 55 degrees it is 79% humidity. And that feels comfortable. In summer, it is routinely in the 80's and 90's% humidity with temps in the 80's and sometimes 90's at mid-summer. No drought around here!
You have to be kidding me 79% humidity is comfortable? Actually, a lot of people have difficulty adjusting to our low humidity, it is not uncommon for it to be below 10% at times. You probably have not seen too much verga in your area, that is when it rains but the rain evaporates before it hits the ground. The humidity is in the upper 50s right now and you can feel the moisture in the air. When the temps get above 80 degrees, the humidity is usually very low, and it does not really get uncomfortable until it gets above 110 degrees.
Our rain fall is about 8 inches a year, and most of that comes in snow in the winter.
I lived in Lancaster, CA for six months in the summer in the early '80s. We got verga once while I was there, it was pretty weird seeing the rain coming down above you, but not getting wet.