Period plastic fuel tank - how to make functional?

[TimB]

I have an original 100 litre plastic fuel tank (type found in 911R) that would look great fitted to a car but I would not want to trust 50 year old plastic with the job of keeping the fuel contained, or me safe for that matter. Any experience of options to make such a tank usable? The tank has a large aperture for centre fill so has reasonable access to perhaps spray some type of lining (?), or I have heard people say 'bag it' without understanding how that is actually done or who supplies/fits the bags? Also what are the implications of any of these actions for using a traditional fuel sender?

Any advice, experience, or contacts I could speak to gratefully received.

Thanks

[BILLY BEAN]

Tim,
a "bag" is in fact a fuel safety bladder. They used to be made to order for specific applications but not sure what is available currently. Try Google. Irrespective of the "plastic" used in manufacturing your tank and the process employed either rotationally moulded, blow moulded or possibly GRP I would not use any "slosh" method to coat the inside of the tank. There would be adhesion difficulties in coating the inside of the tank. Additionally, pretty well all plastic materials are subject to ageing which manifests itself in brittleness and a consequent loss of "strength". This could be particularly problematic as the tank has to bear the weight of fuel. Kirk

[TimB]

Thanks Kirk
Yes I think you are right, pretty much decided that I need to find a secure bladder solution and view the plastic tank as purely a cosmetic skin.
Cheers

[Darren65]

Sounds like the tank is scrap Tim but I'm happy to take it off your hands if that helps!

I've never actually worried about the integrity of the 44 year old plastic tank in my E........should I?

[TimB]

That is a very kind offer Darren

I must admit it is not something I had ever really thought about but then when you think of how plastic goes brittle over time it does makes you wonder; might also be an interesting point for insurers of older cars, how long before they start asking for certified fuel tanks with a maximum age as is the case for competition vehicles?!

[hot66]

same here .. 73 plastic 80lt tank , still use it and still makes contact with the tarmac regularly

[jwhillracer]

ATL and Fuel Safe are two of the main motorsport safety tank manufacturers, but I would think that having a custom bag made to fit your existing tank would be a/ very expensive and b/ involve a considerable amount of cutting up of the tank structure to fit.
I would think that the best bet would be a new steel or plastic tank, and keep the 50 year old 100 litre one with the car as an interesting curio..........
This is the ATL saver cell in the front of our Hillclimb car. The standard tank was just too vulnerable to damage on the underside even after a relatively small "off".



JW

[majordad]

That is a very kind offer Darren

I must admit it is not something I had ever really thought about but then when you think of how plastic goes brittle over time it does makes you wonder; might also be an interesting point for insurers of older cars, how long before they start asking for certified fuel tanks with a maximum age as is the case for competition vehicles?!

Competition tanks are bag lined, it's not always to do with brittleness that makes them lifed, usually it's the foam.

Living in bumpy road Cork I've always fitted a thin metal sheet to my 911s. It's not to witstand blows rather to witstand small scrapes and glancing blows. Never had a problem, but my plastic tanks did begin to suffer before I did this.

[BILLY BEAN]

If you have a "plastic" tank it would be prudent to check it regularly. Look for changes of colour/ tone (usually lighter than the prevaling colour ) of the pigment particularly around areas of potential stress : where fuel lines enter and exit the tank and where the tank sits on the tank support. Any grounding of the underside of the tank is not a good idea and should be checked. I am not suggesting that a non metallic tank will definately fail but a level of circumspection is advisable. Polymer technology and manufacturing sophistication has moved on a great deal in the last 40 odd years. I doubt if the manufacturers of these old tanks ever considered them to have such an extensive life cycle.