The Stovebolt Site Forums The Shop Area General Truck Talk Gasoline Tank Drain Valve Type?

I ordered a gasoline tank shut off valve from Classic Parts USA. Its a 90 degree "needle valve" with 1/8 NPT threads going into the tank and a 1/4 inch compression fitting threads going to the gas line. I'm thinking that this valve should be a "ball valve" instead with NPT threads on each end for use with gasoline. Would this be a better solution? Bear in mind that my truck came with a shut off valve and I want to keep it that way. Not sure that it came with a needle valve off the 1946 production line. Any commits?

On my 39 I used a 90 degree needle shut off valve with a glass sediment filter bowl that screws into the gas tank under the cab. Gas gets filtered before it even goes to the fuel pump.

Rick

I've had a problem (3 times) where the crud in my tank would clog the fuel leaving the tank, and leave me on the side of the road. I've been wondering if using the later float/sending unit type and having it pumped out of the top of the tank would be a better option. The last time this clogging happened to me, my tank was half full. (The other two times it was almost empty, so it seemed reasonable). Also, the last time it happened, it took less than a minute to jump out, remove the input on the fuel pump and blow back through the filter and line till I heard the gas bubbling in the tank, then jump back in the truck, fire it up and go home. Still, it's a pain in the butt. I'm definitely going to remove the tank, clean and seal it, but that's not going to happen till I do a major tear down when I paint it next year (it's my daily driver). So, has anybody else converted to a top style sending unit/fuel line on their 3100?

One advantage of the top float-sender/supply-line tank is that a "sock"-filter was/is used at the opening of the pickup tube.

Needle valve or ball valve? That is what I need to determine which is more ideal for gasoline. The current needle valve is leaking. My gas filter is built in atop my fuel pump with a glass bowl for viewing the filter element as they were originally supplied.

I also have a standard AC glass-bowl carburetor inlet filter on all my 54/55 235/261/270 GM engines, and the sock in the fuel tank, and a glass bowl top when using dual action fuel pump that has one (maybe that is why the glass bowl was not on the 1954 (and later) dual-action fuel pumps)?

I do not know about needle-valve/ball-valve in 1946.

I should have stayed away from this thread, but there was a post about drawing the fuel from the top of the tank. Sorry.

I realize you want a stock outlet. A ball valve would be nice.
Commentary:
If I had that type of tank I would plug the bottom outlet with a pipe plug and find a top pickup/sender that I could modify by copying the configuration of the old sender. The round mounting flanges and the 5 holes are standardized, albeit "keyed".
The bottom outlet and the valves have too many leaks and seem to have clogging issues from what I read.
I have played around with pickup tube senders making a TF truck sender into a suburban sender.
You can bend/cut/modify the float arm and you can bend/cut/modify the pickup tube. I have even modified the rheostat. All to make a new/different sender that, at the time, was not available.
Showme: If 54 has pick up tube senders and the gas tanks are the same as 51, it seems like a direct swap to add a tube sender. Don't see any issue with changing except a little replumb/rewire. The PO's 46 would require some investigation but he wants that area to stay stock for some reason. That means he can't have a ball valve, larger rear view mirrors, no seat belts, no radial tires, no turn signals and shouldn't park inside a garage near a water heater. (just kidding David)

The ball valve on the right would be my choice due to the fact that the I.D. of the pipe fitting is larger than the pipe connection to the tank on the needle valve fitting. Both valves have 1/8 NPT threads, however, needle valve port is smaller. It may be the reason why they are easier to plug up. Just guessing.

Anyway, I was more concerned about the quality of one over the other in this application.

The other thing about this needle valve is I don't understand why you would go from NPT threads which guarantee you a leak proof seal and then on the other side of the valve you switch to a compression fitting. Doesn't seem to make any sense to me.

Another question I have is how seriously does gasoline effect the packing around the stems of each of these valves?
Maybe I'm being over anal about this. I just don't want to worry about leaking gas and the potential of a fire.

I didn't think a compression fitting was used on gas lines in 46.
Anyway I gave my idea to prevent leaks. You don't know what country the valve is from. Or what packing is used and the vendor does not either. You are correct in worrying about leaks.
Better safe than sorry.(or original)
If a person does not want a chance of leak, use a hose bib pipe fitting out the bottom and forget the valve. The valve is 100% absolutely unnecessary.

I have taken apart 3 original tank valves and have yet to find any packing in them. It seems that when they are all the way open, or all the way closed, they seal metal-to-metal. The stem has a compression style hex nut, which again appears to make a metal-to metal seal when snugged up. Disassembly and thorough cleaning has fixed the leaks for me.
Carl

100% agree w/ Carl. That's exactly what I found, too!

BTW, I think David is showing he prefers the valve on the right. I believe that is a petcock. No use throwing in a spring into the mix that may or may not need a certain vacuum to open the valve. If that is what it is, maybe drop that idea and use whatever Carl uses.

So I did a bit of historical searching today and found the following. The swage lock tube compression fitting wasn't invented until 1959.

The petcock was invented in the early 1900's. So, I am assuming that in 1946 that gas tank valve was most likely a petcock. Even on this Ford forum it mentions these types of valves during that era. They make total sense. Their either totally on, or when you want to change the fuel filter on the fuel pump, its easy to turn off especially when you have a full tank of gas.

I just want to keep Lucille as original as possible. I believe that will keep her more valuable. A 70 year old truck that is a survivor is amazing to me. How many vehicles today will make it to 70? I'll be 70 myself in 2017!