computid
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| posted on 29/12/13 at 01:43 AM |
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Moving the filler neck on a fuel tank
Hi all,
As some of you may know the Minari uses a standard alfasud fuel tank as shown here:
Unfortunately, for some reason alfa decided to put the fuel filler on the side at the bottom. A bit silly if you ask me!
When it comes to the Minari, this leads to very poor filling speed (You have to trickle the fuel in otherwise it backs up). As such, I'd like to
do something about it. We've tried moving the fuel filler to the top of the car but this does little for the filling speed. I'd quite like
to move the filler neck from the position above to the position shown here:
This would involve cutting off the current filler neck, welding a plate over it and installing a new one on top. I'd like the filler aperture to
be bigger then it is currently so I imagine I could get a piece of steel pipe, cut a hole in a piece of metal plate, weld it to that and then cut a
square hole in the top of the tank which it can be welded above.
My welding skills are not up to doing this, I don't think I could get a good enough seal around the plates. What I really want to know is, does
this sound reasonable? Can anybody see any issues in doing this?
Secondly, would anywhere actually be willing to do welding on a fuel tank? I presume you'd have to flood it with inert gas whilst cutting it and
welding it in order to avoid an explosion. I would of course drain the tank first!
I'd appreciate some opinions on this. Maybe it would just be easier to have a custom tank made? Does anybody have an idea of how much this would
cost (If I got a custom tank, I'd want it baffled and probably stainless)?
Thanks all!
Adam
[Edited on 29/12/13 by computid]
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mark chandler
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| posted on 29/12/13 at 09:27 AM |
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Welding the tank is not an issue, drain clean then fill with water leaving a minimal gap.
You do have a other options, solder (used on land rovers years ago) or braze.
If mig welding you need to do this in one continuos weld then overlap where you started to eliminate cold start pin holes.
Regards Mark
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theprisioner
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| posted on 29/12/13 at 11:22 AM |
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I have repaired/welded tanks a few times. The key issue is to get rid of any fuel vapours as advised above. Another way of eliminating vapours without
having the tank filled with water is to clean out the tank with dishwasher tablets. I usually plug all the holes fill the tank with hot water, dump in
about 4 tablets, shake the contents periodically and leave for a coupe of days. Rinse and dry with a hair dryer. When you are finished you should not
be able to smell one molecule of petrol. If you can, start again.
The advice given above about shifting the pipe is spot on. Pinholes in any weld/braze is your biggest problem. I have used Frost tank sealers to
eliminate pinholes.
http://sylvabuild.blogspot.com/
http://austin7special.blogspot.co.uk/
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Bigheppy
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| posted on 29/12/13 at 02:15 PM |
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The fill pipe goes into the bottom of the tank to create a 'wet' seal between the fuel and the vapour that fills the top of the tank as
fuel is used. This seal reduces the amount of explosive vapour exposed to the atmosphere and reduces the risk of explosion. I once had the same
problem and it was rectified by ensuring that the vent in the top of the tank had a continual rise and in my case was terminated inside the top of the
fill pipe as the petrol cap was vented.
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