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Fuel backup while filling

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Gearhead_Garage

Gearhead_Garage

Jedi Hopeful
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I have a freshly restored BJ8 which includes a new fuel tank, sourced from Moss I believe. The tank looks to be installed correctly. You can see straight down from the filter cap into the tank so I don't think there are any obstructions. When I fuel the car and get 3/4 full I suddenly get a giant splash back through the filler neck that runs down the paint. I have tried filling at a slower flow rate but it still happens. I do not see anyone else discussing this issue. Is there something wrong with my car or a way to deal with it?
 
How do you know it's 3/4 full maybe your gauge is wrong .How would you not know where the tank was from
 
Check to see if your tank's vent is clear. its purpose is to let air escape as the tank is filled and if clogged or constricted the result will be as you describe.
 
I know it is approximately 3/4 full because it will take another 3 or 4 gallons after it settles down. And I can see into the tank with a flashlight. And I checked it with a dowel. The tank was purchased by the shop doing the restoration. I think I saw the receipt from Moss. This has been a multi year process so some details fade.
 
I was under the impression that the only vent was through the gas cap. Where is the gas vent located?
 
I would give Moss a call I think I read somewhere that they had an issue with their tanks , that's a lot of gas for it not to be filled up I also never knew there was a vent.
 
I agree , the tank vents through the filler tube . There are baffles internally to slow the movement of gas from one side of the tank to the other. I would think there is something not right with the openings in the baffles and you are trapping air in the opposite end of the tank where the filler is up to the point where the built up air pressure can force its way out the filler tube.
 
The tanks baffles will be the problem as stated by Brinkerhoff. They are intended to minimize sloshing of the fuel inside the tank, but yours seem to be very restrictive, trapping the air, as there are no "vents" on these tanks.

Brinkerhoff said:
I agree , the tank vents through the filler tube . There are baffles internally to slow the movement of gas from one side of the tank to the other. I would think there is something not right with the openings in the baffles and you are trapping air in the opposite end of the tank where the filler is up to the point where the built up air pressure can force its way out the filler tube.
Click to expand...
 
I'm sorry guys--I don't know what I was thinking. There IS no vent so disregard my post.
 
I've had these same problems. IMHO, due to the design of the tank & filler, it is best to find a gas station which is not too level and park the car in such a way that the filler is on the high side. You can also "burp" the car by pushing up and down on the back end.
 
As already said there is no vent . What I do is ease up on the nozzle while watching the neck once it starts get close , direct the gas down the side of the neck to try and maintain the airway . I also rock the car with my thigh while putting in the last gallon or so to help burp it as it get almost full . Works every time .
 
That's useful advice. Thanks. Do you think a funnel would help at all?
 
First time it happened to me, I was 16 and working at a gas station in Detroit (circa 1970, when the attendants pumped the gas, and offered to do A LOT more). Point is, at least as far as I know, they've all done it since the beginning of Healey Time.

I did manage to cure the problem on my own car, inadvertently though, not that it's necessarily a popular modification; I have a twenty-eight (28) gallon fuel tank, and its height (double that of a stock tank, with the same perimeter dimensions) required the use of a 45* rubber/fabric hose connector pirated from a late-model MGB, and the steel filler neck tube from an earlier version of same.

I did also install a vacuum-breaker, sort of a check valve, but it's not a vent, per se; it allows air in to replace the fuel that has been drawn out, but wouldn't let fuel out if the shiny-side was down__or allow air to escape during fill ups.

Old habits die hard, but one thing you can do to minimize any gasoline getting onto the paint work, and this may be dependent on the governing fuel dispensing regulations in your locale, is to physically hold the rubber flap surrounding the nozzle tight to the top of the filler neck. Any gas splashed up against it will have to drain back down the tube.

It's been a long time since I've seen a completely naked nozzle, but if you live somewhere that still has them (1. it probably won't be for long...) you could make one up and carry it with you; just need a nice disc of rubber (3" OD x 1/2" thick) and punch a hole in the middle of it.



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How many Healey owners over how many years have filled their tanks without a problem while ignoring slope of station or rocking with knee etc., something is wrong with your tank.
Jay, '65 3000
 
Well, until the 80's or so there wasn't a seal around the gas filler nozzle that prevented the air from the tank being displaced by the gas to escape into the atmosphere. It was introduced to cut prevent these escaping vapors from adding to the air polution.

Personally, I fill up the tank from a 7 gallon can of gas so I can watch the gas going in so I don't overfill the tank into the boot (BN2).
 
why said:
How many Healey owners over how many years have filled their tanks without a problem while ignoring slope of station or rocking with knee etc., something is wrong with your tank.
Jay, '65 3000
Click to expand...

The composition of the gasoline has changed and is more volatile. That is more likely to be the problem here, rather than there being anything wrong with the tank.
 
I spoke with Moss tech support. They claim no knowledge of such problems so I guess I'm on my own to find a solution. I will try a few things and post back here.
 
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