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  #1  
Old 20 April 2007, 05:18 PM
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Glasses Ping-pong ball in the gas tank

Comment: I heard a rumor years ago. It says "when if you put a ping pong
ball in a gas tank, the car will stall out." I guess this is supposed to
happen when the ball floats to the gas line. Is there any chance this is
true?
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  #2  
Old 20 April 2007, 05:40 PM
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Since the gasoline will dissolve the ping-pong ball, it may well be true. Or maybe it'll just make the engine ping.
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  #3  
Old 20 April 2007, 06:21 PM
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Quote:
Originally Posted by Brad from Georgia View Post
Or maybe it'll just make the engine ping.
Or possibly Pong...


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  #4  
Old 20 April 2007, 07:50 PM
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There's usually an anti-siphon/large-piece-of-crud screen in the neck just beyond the spot where a std fuel pump nozzle ends. At least there is in my car. That would prevent a ping pong ball from making it all the way to the tank. Also, the fuel pickup in most tanks is toward the bottom, and usually has a filter screen of its own.

So, doubtful.
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  #5  
Old 20 April 2007, 08:00 PM
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DrRocket hit it right on. The fuel pick up is at the very bottom of the tank. It also has a screen on it. There is no way a ping pong ball could be picked up into the fuel lines. No way at all. The ping pong ball, if it doesn't dissolve, will float on top because it's full of air.
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  #6  
Old 23 April 2007, 09:37 PM
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Putting a ping pong ball in the gas tank may have been possible with some older cars, but I believe most in most new cars, the filler hole in the tank is too small to accept a ball that size. I have also heard of cars that are equipped with screens or bars just below the filler hole to prevent debris from even entering the tank and supposedly to prevent theft of fuel as well.
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  #7  
Old 23 April 2007, 09:54 PM
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Stupid question, but would the ball have to enter the fuel lines in order to block the fuel flow?

Suppose I put a small kiddies soccer ball (5-6 inches diameter) into a full bath and remove the plug. There is no way it could enter the drain, but the suction created by the exiting bathwater would keep it pressed against the entrance to the drain, maybe intermittantly, but enought to interfere with the smooth flow of water.
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  #8  
Old 25 April 2007, 05:56 PM
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Quote:
Originally Posted by Eddylizard View Post
Stupid question, but would the ball have to enter the fuel lines in order to block the fuel flow?

Suppose I put a small kiddies soccer ball (5-6 inches diameter) into a full bath and remove the plug. There is no way it could enter the drain, but the suction created by the exiting bathwater would keep it pressed against the entrance to the drain, maybe intermittantly, but enought to interfere with the smooth flow of water.
That might work in a bathtub, but there are a couple of major differences between that & a tank. In a tub, the drain is at the bottom, pointing down. So, I suppose, if the level of the water got low enough, the ball (which should be floating) could block the drain. In an automotive fuel tank, the pickup is at the bottom of the tank, but it usually points to the side, or upward. By the time you gas level got low enough for the floating ball to be sucked by the fuel lines, you are pretty much out of gas anyway, if it could get suction with the sock on there.

ETA: See this link right here. There is a picture of a modern automotive sending unit/fuel pump assembly. At the bottom right of it, you will see the float (tells your gas gauge where to point) and the sock where the fuel is picked up. That sock sits right at the very bottom of the tank. I think it would be doubtful the pump could get enough suction on any single thing with the sock on there.

The only way I see a ping pong ball clogging up your lines is if it partially dissolved, and the gunk from the ball plugged the screen, or fuel filter.

Last edited by Monza305; 25 April 2007 at 06:03 PM.
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  #9  
Old 25 April 2007, 06:25 PM
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I always heard it was supposed to be a "superball," not ping-pong ball.

Soemthing about the idea of the "draining vacuum" of the gas would suck the bal ontop of the drain blocking flow. After the car stalls, the vacuum is released the seal is broken. The car will start again, until the vacuum pulls the ball back on top of the drain.

Don't have a clue if the superball is dense enough to sink or if it will dissolve in gasoline...
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  #10  
Old 04 May 2007, 12:47 AM
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I wouldnt try this..., but i think that if there were some holes in the ping pong ball, it could slow down fuel when it got sucked down
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  #11  
Old 04 May 2007, 03:00 PM
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Hey! I saw this on "Law & Order: Criminal Intent," so it must be true!
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  #12  
Old 04 May 2007, 03:52 PM
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Quote:
Since the gasoline will dissolve the ping-pong ball, it may well be true. Or maybe it'll just make the engine ping.
Exactly. The ball will be dissolved into goo, which will eventually be sucked into the fuel line/fuel pump and block it, causing an angry car owner and a happy and slightly richer mechanic.

It has nothing to do with the ball getting sucked into the outlet and blocking it, a car drinks way too little fuel to suck it anywhere. The sloshing of the fuel caused by driving will exert a much stronger force on it.
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  #13  
Old 04 May 2007, 04:40 PM
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What about marbles? I bet 30,000 marbles would slow things down.
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  #14  
Old 04 May 2007, 04:50 PM
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Th filler hole on my car is only about 2/3 the diameter of a ping pong ball. You could only get one in there if you deformed it in some way. I doubt if you could get it all the way into the tank without poking it down with a length of wire - it would just get stuck in the filler tube.

However that begs another question - presumably as the petrol is drawn into the engine, air has to be drawn into the tank to even out the pressure. Does that air get drawn in through the filler tube (is that the right term(?) the one leading from the outside of the car to the tank) or through another inlet?

If the former is true, then could blocking or restricting the inflow of air through the filler tube lead to the fuel pump struggling against the pressure difference and eventually starving the engine?
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  #15  
Old 04 May 2007, 05:03 PM
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Quote:
However that begs another question - presumably as the petrol is drawn into the engine, air has to be drawn into the tank to even out the pressure. Does that air get drawn in through the filler tube (is that the right term(?) the one leading from the outside of the car to the tank) or through another inlet?
I'm not sure about this, but there is a pipe that goes back from the engine to allow any fuel in the system to flow back into the tank when the engine is stopped (I could tell a story about a mechanic who was told to fix my car when it was leaking petrol and replaced an almost new tank and said it was fixed even though it still leaked. It was that pipe that was broken. But it would be a long story, so I'll skip it.). I think this may also be where air is sucked in, but as I said, I'm not sure.
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  #16  
Old 04 May 2007, 07:59 PM
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The vents totally depend on the age of the car. Some of the really old cars just vented into the air. Most newer ones have one way valves somewhere that allow air in, but not out. Sometimes they are in the filler tube/gas cap, sometimes in the top of the tank, sometimes part of the fuel pickup/sending unit. The newer the car, the more sealed off the whole fuel system is. On newer cars, sometimes you can hear the tank hiss when it loses vacuum when you remove the cap. I know older cars aren't like that.

I've actually got a little spare time here at work, I'll try to take some pics of a typical fuel tank and sender to better illistrate what we're dealing with.
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