I have a Vintage Speedster and when I fill the fuel tank it will overflow out the overflow tube when I turn left.
any way to resolve this problem?
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They make one way valves for this, that let air in but no gas out. Caveat: If you park your car for a long time when weather is warm and the tank is not full, but has some gas and some air/vapor inside and it gets cold (winter storage), air will go in from outside. Then if it gets warm again, that vapor mixture will try to expand and cant get out --- unless it has enough pressure to defeat the fuel pump and the float valve in the carb. If the tank was pretty empty, lots of vapor will result in lots of pressure build-up. Then the carb will flood bigtime, and that gas can get right into the engine, fill up the crankcase. If you miss that happening, and fire up that engine in the warmer spring air you can cause much excitement, due to copious smoke. Ask me how I know ... N.B.: I take the rubber tube (without the one-way valve) at the top of the tank, and run it down the side of the tank for a bit then turn it back up, making a big U trap. That pretty much takes care of the slopping out of gas through the open tube. Try that, might work for you, or at least minimize the problem. If you fill it to the tippy top, you are going to get some gas smell more than likely. Further: its a good idea to top the tank off before winter storage -- and toss in some SeaFoam a few miles before you button it up. Or . . . live in sunny SoCali and just forget about ever getting really cold, just drive it all the time.
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This has been a known issue for years with older Vintage Speedsters, but is easy to fix.
Fuel is sloshing out the vent tube and dribbling down in the wheel well under the car.
An easy fix is to replace the hose with one that's much longer and that can be looped up high inside the wheel well.
Click this link for some discussion on an earlier thread. Further searching here will reveal many similar threads.
I bought a check valve but after thinking about it for a minute longer, deemed it useless because isn’t its main purpose to prevent fuel from leaking out of the tank on a rollover? Maybe if the exit end is higher than the entrance it might help on left hand turns. The 356 loops of hose sounds like a good option.
That is NOT an "overflow" tube. The small tube on the side of the filler neck is a breather to let air into the tank as fuel is used by the engine. If left just as a hose, there is nothing to prevent fuel from running out on cornering when the tank is full (as you've noticed).
The positive cure, regardless of the length of the breather hose, is to install a check valve in that breather hose more-or-less close to the filler neck (within a couple of feet). There are a bunch of them with varying flow rates. I use one of these from Dorman:
https://www.amazon.com/Dorman-...gid=pla-570433919734
When you get it, blow through each end. One way will not let you blow through it, while the other direction will. Put it in the hose so you can blow through it into the tank. That will let air flow in, while preventing gas from flowing out.
Gordon, in this configuration, would I need to worry at all about pressure build up on hot days. My valve works like you mentioned, but it is just a ball valve. It should be mounted upright so air escapes but fuel would not if you’re upside down. Would it work for our purpose do ya think?
Always learning,
Tom
Gotno - I don’t have any issues with my vent check valve regarding pressure build up on warm days.
As far as using the check valve you bought, I don’t see why not. With the car right side up it allows air to pass through the valve into the tank. Flip the car over and the ball seals the hose to prevent gas from getting out.
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I should like to point out that I have no valve.
Not a high pressure valve nor a low pressure valve.
Not an inside out valve. Not an outside in valve.
I have no valve at all.
I also have no gas fumes.
What I have is a hose.
It has two ends and a middle.
It does not matter which end connects to the tank as long as the other end does not connect to the tank.
By virtue of the hollow nature of the hose it relieves pressure in any condition. When it’s hot and when it’s not. When it’s humid and when it’s dry. When it’s summer and when it’s winter. Day or night. Rain or shine.
My hose is a simple device.
It has no moving parts.
I do not like valves in a house.
I do not like valves in a mouse.
I do not like them here or there.
I do not like them anywhere.
I do not like green valves and ham.
I do not like them, Mitch-I-am.
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Per Mitch: if the hose is arranged such that its highest point is higher than the highest point in the fuel tank, it won't drip gas. The other trick is to pinch the little pipe it attaches to on the filler neck so it's almost closed.
I had a check valve that let air in but not fuel out.
A full tank of cool gas warmed and expanded causing the top of the tank to bulge up requiring replacement.
So, no valve for me now.
WOW! I just purchased my car and already i have a whole community that can support me!
i really like all the input.
the car is on Maui so i don't have the significant weather variations.
i will try to come up with some other attempts to stump the stars,
Bob
Spyders have no hoses, valves, and all that other complication.
Spyders have a spring loaded cap. It self vents from excess pressure, and sucks in air when it needs to. And they don't spill gas.
I kinda like it that way.
@RH3 posted:WOW! I just purchased my car and already i have a whole community that can support me!
i really like all the input.
the car is on Maui so i don't have the significant weather variations.
i will try to come up with some other attempts to stump the stars,
Bob
If you live in Kihei, I need to buy you a beer. Maui Brewing Company? PM me so I can get up to speed on your marvelous new acquisition!
Ahhhh.... The beginning of the "Maui Replicar Owner's Group"
Gonna have to get a Spyder or MG-TD over there, soon!
Pressure build-up, as described, is real, it happened to me, and sets up if: you have a one-way valve, a fair amount of vapor in the tank and temperature swings are significant, like you park it on a 70 degree day, and over the winter it goes below freezing, then warms up to 70 again. Looping the tube without the one way valve, as described, limits slosh problems. Ed says pinch the tube -- Ed is always doing clear thinking. Or get a Spyder gas cap -- I like that too.
Fwiw I also vented my Spyder’s tank, for originality’s sake.
@Robbie Haas That is just to take care of water/rain that enters the through-hood filler area.
The gas smell from the your car is most probably from the float bowls in the carbs. I changed my Spyder over to fuel injection, and no longer get the smell. I have retained the same gas filler I had before.
makes sense, overflow egress also. thanks!
what fuel injection system did you use?
Speeduino with CB Performance throttle bodies. It's not a "kit" or a "buy-and-fire-up" thing. I bought every part and piece, plumbed it, built the harness, programmed it and tuned it.
I used a UA4C ECU from Weaver Markel(WTM). Surface mount boards assembled in USA. You have to solder the pins for Arduino(8-bit computer), solder board options, a VR conditioner, and an IAC controller if you're using one.
https://wtmtronics.com/product/ua4c-for-speeduino/
It's a big project, not for the timid.
Impressive! I’ve played with a raspberry pi a bit but the necessary skills are beyond me!
Thank you. I did a build thread on it(closed thread now) but it's all there.