Petrol tank return

Any Technical Queries? This is the place to ask/give advice.
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prop
Posts: 175
Joined: Fri Apr 23, 2010 2:28 pm
Location: Leeds

Petrol tank return

Postby prop » Mon Feb 01, 2016 2:51 pm

I have a problem with my petrol tank. Ever since I rebuilt the car I have always had a faint whiff of petrol. Not really noticeable while driving but there after being sat for any time. Made all the checks on pipes etc no difference. The tank was second hand and I brazed the return into it at the top where ERA did. I have a brand new tank, not ERA, and I need to fit a return. When I brazed the return pipe in the second hand tank it caused a lot or oxidisation on the inside that gradually dropped off and blocked the filters, as I reported on this site earlier. What I would like to do is coat the inside of the tank as it is new, and don't really want to heat it up before I coat it and have the coating come off where the oxidisation is and cause me filter problems. I though if I could find a compression type fitting then problem solved but I cant seem to find one.

Anyone with any suggestions on how or what to do for the best would be appreciated.

kayball
Posts: 51
Joined: Sat Feb 03, 2007 7:11 pm

Re: Petrol tank return

Postby kayball » Mon Feb 08, 2016 3:06 pm

The inlet return pipe on the fuel tank fitted to the ERA enters the top of the tank at the inside front end, then turns at a right angle to traverses across the tank to the inside face, just down from the top, and ends almost touching the inside wall. This I assume is to prevent the returning fuel from the regulator splashing into the tank. Forcing it against the inside wall of the tank keeps splashing noise to a minimum.
First query, is this necessary in practice?
Regarding your suggestion of using a compression fitting I cannot find anything suitable except in the common 15mm size. Stainless gas pipe fittings are common in metric 8mm and 10mm but not tank connectors. Looking at the tank, it would be possible, but difficult, to fit a standard 15mm compression Tank connector from the inside, complete with fibre sealing washer and nut, by access through the fuel sender location. This would then allow an external 15mm to 10mm copper reducer and any further soldered pipe fittings to be attached via the compression joint. Unfortunately this does not provide the cross feed to the inside wall as originally provided.
When you brazed the pipe to your first replacement tank, did you transfer the original pipe with this cross feed? If you want to try the compression route utilising a cross feed , I would suggest that you manufacture a flange plate to hold the preassembled pipe work with sufficient diameter to allow the cross feed to enter the tank.
This flange plate could be fitted using SS self tappers around the periphery, sandwiching a suitable gasket and sealant.

Why can’t you clean your modified tank more thoroughly? We have cleaned ours using electrolysis and I have written an article about this. It is very effective and quite cheap; much better than rattling screws or broken windscreen glass inside! It’s a bit long for the Forum, but if you send me an e-mail to: kayball@ntlworld.com I will send anyone on the list a copy.

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prop
Posts: 175
Joined: Fri Apr 23, 2010 2:28 pm
Location: Leeds

Re: Petrol tank return

Postby prop » Thu Feb 11, 2016 8:13 pm

Good article Peter.
I will definitely use that method.
Thanks


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