Overflowing fuel filler?

rosenkranswa

rosenkranswa

Senior Member
A couple times now I've had a problem filling the tank on my '29 Roadster. I would put maybe 7 or 8 gallons in the tank, pull the filler out while the level was visibly well below the opening and watched the fuel level continue to rise until it overflowed. Never done it on any other Model A or T I have. Had it happen twice in the Fall, and once in the Spring. I'm guessing it has something to do with the relative temperature of the gas going in vs the temperature of the tank itself causing the gas to expand. Very annoying when it happens and nothing to do but watch gas spill all over the cowl. Anybody else experience this?
 
Hi Wayne,

When filling a Model A tank out of a gas can, through an open funnel, this usually never happens.

If filling a Model A gas tank out of a gas pump with the large round rubber anti-back-splash device, un-vented air can get trapped in the tank until one removes the nozzle ...... then after the seal is broken after the nozzle is removed, very similar to a human physical reaction with excess interior air, the gas tank burps, (in this case, naturally, from the "top" end), and forces liquid gas out of the tank

Not to be facetious, but one (1) other guess if this happens "without" trapped air:

Might have something to do with one's daily zodiac signs.

If it were me, next time it happens, I would try depositing $1,000.00 in my savings account to see if it overflows.

One will never know until one tries it ..... stuff happens !
 
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H. L. Chauvin said:
If filling a Model A gas tank out of a gas pump with the large round rubber anti-back-splash device, un-vented air can get trapped in the tank until one removes the nozzle ...... then after the seal is broken after the nozzle is removed, very similar to a human physical reaction with excess interior air, the gas tank burps, (in this case, naturally, from the "top" end), and forces liquid gas out of the tank
Click to expand...

Shouldn't the pumps vapor recovery system "vent" any pressure in the tank? I believe most modern stations have them now. If it has a "large round rubber anti-back-splash device", it more than likely is a vapor recovery system.

I use a tank extension when filling my tank, don't know if it will prevent your problem but it does help support the nozzle. http://www.snydersantiqueauto.com/gas-tank-neck-extension

 
After re-reading your post, and again just trying to get back to your initial "question"?

"pull the filler out while the level was visibly well below the opening and watched the fuel level continue to rise until it overflowed ...... Anybody else experience this?"

After 58 years of filling Model A gas tanks, never experienced this phenomenal event with a Model A gas tank.
 
I always hold the nozzle while filling to keep the black rubber shield from seating and to monitor level, so the tank is fully vented while filling. Bizarre to watch when it happens - I've about decided it's a gremlin...
 
Hi Wayne,

Thanks for reply no. 5, and if all else fails, maybe find a filling station next to a bank, or one with an ATM, and try the Savings Account Trick immediately before or after this "overflow" event happens.

Please let us know .... you may have discovered an unknown mysterious method on how to successfully bank with your Model A.
 
Hi Wayne,

Your subject, could be the most interesting Model A Post ever posted where everybody's cup is "overflowing" ............ plus with the mystery resolved, with "overflowing Model A gas tanks", we never have to buy gasoline again.
 
It sounds like you are using a screen.I had something like this happen with one design of screen,but I don't remember if it was the screen,perforated,or slotted opening type.As gas is being pumped in through the screen,the air is not allowed out because the gas rushing in is holding it back.As soon as the gas stops flowing it burps itself out.It's really just a little bit of gas that overflows,but it looks like a lot on your car.
 
The post doesn't seem to mention whether the spark arrestor/ screen is used.

But, my suggestion also is to remove it if being used and see what happens.
 
Too many JC Whitney parts on the car. Everything JC Whitney sells saves you 10% fuel economy, pretty soon you've got so much savings that you have to drain out a little gas every once in a while!
 
rosenkranswa said:
A couple times now I've had a problem filling the tank on my '29 Roadster. I would put maybe 7 or 8 gallons in the tank, pull the filler out while the level was visibly well below the opening and watched the fuel level continue to rise until it overflowed. Never done it on any other Model A or T I have. Had it happen twice in the Fall, and once in the Spring. I'm guessing it has something to do with the relative temperature of the gas going in vs the temperature of the tank itself causing the gas to expand. Very annoying when it happens and nothing to do but watch gas spill all over the cowl. Anybody else experience this?
Click to expand...

Had it happen 2 times myself I wouldn't say it was well below the filler, but it was below then started to rise and overflow. No screen in the tank and no rubber whatevers on the nozzle. I attributed it to the gas being cool from the ground storage and expanding in the tank as it warmed up and overflowing the filler. Real pain in the a__. much more careful now on how full is full:o
 
Yea, somebody else has seen this problem! I do think it has something to do with relative temperatures of the gas vs the tank in the car. Strange I would only see it with the '29, something to do with the design of the tank maybe?
 
Once I filled the tank to the top on a summer day. Then I watched as the gas expanded and ran out of the top of the tank and down into the engine via the gap in the engine cover !

Marc
 
Yea im leaning towards a hot tank since unlike a modern the sun can reach it. The gas comes out of the ground relatively constant year round and if it hits a hot tank it can expand. Ever leave one of the plastic non venting gas cans in the sun? looks like a bomb is gonna go off...

Even in my modern once the pump clicks off automatically i can hear the fuel neck gurgle and bubble and sounds a bit frothy so could be a mix of things.
 
Hi Wayne,

Never thought of this before, i.e., that gasoline stored below ground further north could be at a lower temperature than gasoline stored underground further south.

Years ago, after hearing about the differences of "water" cooling residential A/C compressor coils as opposed to "air" cooling same with the additional cost of operating an electric fan motor, I remember measuring the water temperatures of water in the month of July, immediately drawn from two water wells, where one was further north, one was further south and they were about 200 miles apart.

In 200 miles, there was about a 20 degree rise in the well water further south.

Appears what this information may mean, depending on various locations, (even in mountainous regions with melting ice), is that this fuel overflowing possibly caused by expansion is more likely to occur where the ground temperature is cooler.
 
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Several years ago I cut apart a trashed 29 tank that had been doused several times with a tank sealer called 'creme' or something. It was off-white and thick as pancake batter. The tank slosh dividers were glued (with plenty of rust and scale) completely along the tank top in the left and right engine side corner sections. No way for air to vent above them! I can only speculate that such trapped air pockets could expand and play havoc during a fill up. The dividers were never intended to be completely sealed against the top.
 
2 stories:

We were on a tour with our Model As. I was driving a friend's '30 Tudor. We stopped for fuel about an hour into our trip, it was still early in the day. I filled the tank up to the brim, not thinking about expansion. Well it wasn't but a couple of minutes till it started to overflow out the vented gas cap. What a mess!

Years ago, my Dad & I were on a trip from Las Cruces NM to OKC. It was an early spring morning, I think it had even dipped below the freezing mark the night before. We stopped for fuel at a country gas station that had above ground tanks and filled up. The fuel never overflowed the tank since we immediately took off on our journey, but we got the best mileage on that tank of gas that my dad had ever recorded in that car. (He was very meticilous about keeping track of such things.)
 
I don't think I've ever "filled" mine more than 2/3rds full, only seen gas in the gauge a couple of times. NO problems.
Paul in CT
 
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