Ethanol in Fuel

(Updated 22 June 2012)



I am not an expert in subjects connected with the use of ethanol in fuel and it's possible effects on classic car engines and their fuel system so, as an Austin Champ owner, this is my attempt at trying to understand the subject.
These notes are an amalgam of reading articles from the web and magazines and from the FBHVC magazine (No. 2, 2012) on ethanol and its effects.

There are grave concerns that ethanol in fuel can damage a classic car's engine and fuel system and that ethanol has already caused damage on the continent (France, Germany, etc.) where the ethanol content can be up to 10% - in the UK it is up to 5% in regular unleaded fuel.
Labelling: currently in the UK only petrol with an ethanol content over 5% has to be labelled as such. Fuel with 10% ethanol is likely to appear in the UK in about 2 years and, at this time, there are no proposals that fuel with 10% ethanol will be labelled - although it might be labelled, E10, as in some parts of the continent.

There are two main considerations with the chemical ethanol:
- it absorbs water (hygroscopic)
- it can separate from petrol - especially if petrol is left standing for a long time - and the result of this can be an acid that destroys components in a fuel system by acid corrosion.

The effect of ethanol on the engine:

- there are reports of increased piston and bore wear and problems with spark plugs - the engine's mixture strength may need to be adjusted to richen the mixture to counteract the leaning effect of ethanol.
The effects of ethanol on the fuel system:
- corrosion of the fuel filters, pipes, fuel tanks.
- increased volatility leading to vapour locks in the fuel supply.
- questions have also been raised about bacterial growth in fuels containing renewable (from grown plants) fuel components. The additives tested by the FBHVC (Federation of British Historic Vehicle Clubs) do not offer any protection against bacterial growth, which generally requires water to flourish. The main risk of bacterial growth lies in diesel storage tanks where water is present, and fuel is stored for long periods.

The (nearly) good news if you believe ethanol can damage engines and fuel systems on cars that were not designed for ethanol in fuel - a figure of 4,000,000 (some people say, 8.6 million) vehicles not designed to use ethanol fuels in their engines and fuel system in the UK is being quoted - is that the FBHVC has done tests on additives to counter the effects of ethanol.
The reason for the '(nearly)' above is that it seems that the FBHVC tests were not comprehensive tests but only covered corrosion, (by the editor of Practical Classics magazine), "As a result we are no closer to knowing the effect that ethanol has on a classic car's fuel system and engine."


This part looks at the worst case scenarios:
The Austin Champ is now around 60 years old, so just normal rust alone on the fuel lines and petrol tank can be a problem, now add ethanol to this. A fuel tank could burst on the road or, worse, in a garage.

Fuel vaporisation is a known problem since the Champ was first built - ask an ex-serviceman who used Champs in the desert - ethanol is more prone to vaporisation than fuel without ethanol.


Is fuel still being sold that has no ethanol in it?, possibly, yes. It is said that some premium fuels, but not all, do not contain ethanol. There is a website by James Stocks, Ethanol in Diesel and he uses Shell diesel fuel and has not suffered from engine oil being diluted by diesel - this website should be read by anyone with a diesel engined car, especially an older one. But does Shell petrol contain ethanol? - if anyone could do some research on brands of petrol in the UK that do not have ethanol in it would be very helpful, below is from one forum.
from About Shell Ultimate 'I asked BP whether Ultimate contains ethanol?'
Their reply: "In most regions of the UK our Ultimate Unleaded does not contain any Ethanol at present (South West UK excluded). Our fuel complies with the specification BS EN 228, which permits up to 5% ethanol by volume. However, there is no minimum ethanol requirement. Consequently, fuel within the UK could contain between 0 and 5% ".

Update from the FBHVC's magazine as at the end of April 2012: these are fuels listed that may not contain ethanol:

petrol without ethanol

Separation of ethanol in stored fuel. Could the rear of a Champ be bounced up and down to remix the ethanol and petrol?, I wouldn't guarantee this method! We all know that any vehicle should be taken out on-the-road at least once a month to fully warm the engine, gearbox, axles, etc. and to use the brakes. If a vehicle is not used it's not that long before damage is done to the tyres, brake cylinder rubbers, etc. How many of us know we should do it but actually do it?

Bursting fuel tank and\or fuel pipes leaking. This applies with all older vehicles let alone now with ethanol in the fuel. The worst case is a full tank bursting in a garage, especially if attached to a house. All electrical fittings in a professional workshop should be flame\spark proof but won't be in a domestic garage and a danger is going into a garage and immediately switching on a light and ....., always sniff the air before turning anything on. One further thought, what if a tank burst and there are other electrical appliances that are automatic and will spark on start-up?, like a fridge.

Should a vehicle be kept in a garage with a full tank of petrol or nearly empty? It is generally said that it is better to keep a car's tank full because most corrosion occurs at the meeting of the fuel's surface and fuel tank, which, if below full allows maximum corrosion. The contra argument is that if a full fuel tank bursts then the most petrol leaks out. My Austin Champ tank is kept full but I have had the petrol tank out, checked it and given it five coats of paint to stop corrosion - keep full or empty?, your choice.

Vaporisation. The Austin Champ is poorly designed on the fuel supply from the fuel pump to the carburettor, the fuel pipe runs against the engine block behind the water pump. It is a known weakness on Champs of breaking down in hot weather from fuel vaporisation, even on the open road and even more prone if, say, driving slowly around a show or in traffic, I know, it happened to me - either wait for everything to cool down or pouring cold water over the fuel pump can help. Now add the increased volatility to this.
The first solution is to wrap the fuel line from the pump to the carburettor in insulation material - some owners of classic cars have re-routed fuel pipes to get over the problem but I shall just wrap the fuel pipe.
Some owners have changed the fuel system from the original engine driven fuel pump to an electric fuel pump mounted in the back of the Champ (type of electric pump, 24v, low pull, high push) but I have not had enough problems to do this.
Additives. The additives that passed the FBVHC tests are: from FBHVC
The page the additive recomendations are on is an interesting read.
Millers' Oils, VSPe Power Plus: email:; Millers Oils
Frost A R T Ltd., Ethomix: email:; Frost
Flexolite Ethanolmate: email:; Flexolite


I think there is going to be a problem with ethanol in petrol, especially at 10%. On a 'belt and braces' approach I will use BP Ultimate (or other brands) petrol with no ethanol and one of the additives above. Tip: I don't use supermarket fuel.

Any thoughts?