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Aluminium and Ethanol
SteveWalker - 1/5/21 at 10:27 PM

I am currently replacing my fuel level sender and tank outlet/return connections due to a corroded and failed sender and (with the impending increase in ethanol content in mind) I am also replacing the additional copper pick up pipe (added as a main/reserve system). Bearing in mind the changes due, it is probably time to replace the fuel hoses and front to rear pipes (one copper and one plastic).

My new pick up and return tubes are stainless steel, as is the tank, so no problems there, however, it would be cheaper and easier to use aluminium to replace the existing "hard" pipes. However, some sites are saying that the new fuels will destroy aluminium, while others are saying exactly the opposite and actually recommending that people replace GRP fuel tanks with aluminium ones!

Has anyone any definitive answers as to whether aluminium is safe with E10? How about higher concentrations?

perksy - 1/5/21 at 10:39 PM

Sorry can't help with your query, although I believe it attacks the solder in copper floats etc, but my understanding is the changes won't effect super un-leaded for 5 years, so that could be used instead of normal un-leaded in the interim?

femster87 - 1/5/21 at 10:41 PM

https://www.coleparmer.com/chemical-resistance

Material compatibility chart. Shows aluminium compatibility with ethanol is good

SteveWalker - 1/5/21 at 11:31 PM

Thanks for that. I can't understand why so many sites are saying that it attacks aluminium - including the AA, yet others are recommending using aluminium tanks! It's nice to see something more definitive.

motorcycle_mayhem - 2/5/21 at 10:03 AM

quote:
Originally posted by SteveWalker
Thanks for that. I can't understand why so many sites are saying that it attacks aluminium


Probably because ethanol doesn't attack aluminium in any meaningful way. Unfortunately, ethanol isn't 'just' EtOH, there are other components, one of which is water. This does cause the issues. You can't get the water out of the ethanol, but ethanol will quite happily absorb more water. It'll quite happily extract it from the air until it becomes a biphasic mixture, starting a cascade of other insoluble rubbish.
I have NO idea how 'pure' or dry the ethanol is when it's sloshed into the road tanker, especially on a dark wet night, but I'll guess it isn't very...

Last time I put some '99' Octane supermarket fuel down the GC-MS it contained very little HC content, the majority was a mixture of alcohols (MeOH, BuOH + various isomers, i-PrOH....). Others are following suit. Thing is with 'petrol' you simply don't know what you're buying, period. As a Chemist, I find it a tad disconcerting that there is not even the loosest standardisation of component ranges.

Canned fuel (see Carless, AAOil, etc.) is a way to go if you're racing.

When running Methanol in the race car a few years back, even the internally anodised fittings didn't last long, let alone the fuel pumps. MeOH is more hygroscopic with more acidic impurities too. PTFE is your friend (e.g. 811 Goodridge and others), or any lesser plastic. Nitrile rubber is good, but consider it a consumable.

chillis - 2/5/21 at 10:33 AM

The answer to this is yes and no. Depends more on how you use or rather don't use your car. The ethanol eats certain types of rubber in fuel lines, seals and accel pump diaphragms, while the acid caused by the ethanol absorbing moisture from the atmosphere dissolves tin, zinc and copper (this happens quite slowly BTW). If enough moisture is absorbed then it can drop out to the bottom of the tank or float chamber where it can corrode aluminium and steel.
If you use your car every day and get though a tank full say once per week then you really only need to worry about the rubber parts since the fuel doesn't hang around long enough to absorb damaging amounts of moisture. If you car is infrequently used and kit cars often are then it will become a problem. There are however some solutions, quite literally. Short term just switch to super unleaded, expensive in the longer term and since there is only a five year reprieve not really a good idea if you plan to keep and use the car beyond 2026. Briggs & Stratton fuel fit is another good option (I was put onto this one by some classic bikers) it has something in it that neutralises the acid created in the 'stale' ethanol so protects against corrosion, I believe Castrol Valvemaster may do the same but haven't tried it yet.
I'm planning to run an Ally tank, with stainless fuel lines and fittings plus E100 compliant rubber hoses and use the fuel fit for full coverage.

HTH

[Edited on 2/5/21 by chillis]

pigeondave - 3/5/21 at 07:26 AM

Esso Synergy Supreme+ 99 doesn't have ethanol in some parts of the country. But it is expensive.

Have a look for yourself
https://www.esso.co.uk/en-gb/fuels/petrol

mgb281 - 4/5/21 at 12:36 PM

There’s a couple of things that you can do to help reduce the problem, the first is to keep the fuel tank full to the top, if there’s no air in the tank there will not be any moisture to be absorbed by the ethanol, it’s a pain to do but it works. The second thing that you can do is to fit a charcoal canister for the fuel tank to breathe through. The moisture is absorbed by the charcoal, as are the fuel vapours. A pipe from the charcoal canister to the air intake will ensure the moisture is removed. You need a sealed filler cap, a bonus is that you will not have petrol fumes in the garage. There’s plenty of cheap canisters on EBay.