E10 fuel in Classic Cars (again)

Admin, Wed Sep 01 2021

There is so much information, good, bad and missleading being posted re the use of E10 Fuel that I'm posting the following directly taken from the HCVA website:

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Prophets of doom are suggesting that the increase in bioethanol content in UK petrol is going to kill classic cars and/or set them on fire. It is a danger if you have deteriorating, incompatible components in your fuel system, but it isn?t the end of the world: Brazilian historic vehicles have been running on 25% bioethanol since the 1970s. There are some issues, which we will discuss, but it certainly isn?t as big a nightmare as some suggest

What is the current situation?

Until recently, all pump petrol was rated ?E5? and contained up to 5% bioethanol (some E5 contained no ethanol). Now it is E10 and contains between 5.5% and 10% bioethanol. Almost all 95 octane fuel previously contained near 5%, but the situation was ? and remains ? different for higher octane fuels. The ?up to? element varies not so much between different fuels as between different parts of the UK. For example, Jet Ultra Premium is ethanol-free except in Yorkshire, Humber, Teesside and Scotland, where it contains 5% ethanol ? and the situation is almost identical for Esso Synergy Supreme+, except that it may contain ethanol in North Wales, Cornwall and Devon too. This is because in areas where demand is lower, fuel companies rely on supplies from a third party that blends up to 5% ethanol in premium grades.

What is changing and why?

The government committed to a target of 9.75% of all transport fuels coming from renewable sources by the end of 2020. Bioethanol is fuel made from refining plants such as sugarcane, maize, potato, cassava and hemp. Waste organic materials such as waste wood are also increasingly used. Ethanol fuel is ethyl alcohol ? the same type of alcohol that we drink, and logically so, as both are extracted from plant matter. And just as excess alcohol consumption can damage our internal tubes and systems, so it can with cars.

As is often the case, USA is ahead of UK, with 10% ethanol standard since 2011. Users report few issues other than having to adjust the timing ? though that is really an octane issue. If the E10 fuel is of the same octane rating as the fuel you were previously using, no adjustment should be required. It?s also been in much of Europe for several years now, again with few issues reported.

It?s worth noting that ethanol itself is an octane booster, even though it?s currently being used in higher concentration in lower octane fuels ? so removing it, as has become popular in some countries especially USA, is not necessarily going to help your engine run better. As well as the health and safety issues, removing it will lower the octane.

The Government has provided an E10 check website which is helpful for younger classic vehicles, but it?s worth noting that it errs (correctly) on the side of safety. For example, all Rover cars to the end of production are stated to be incompatible with E10 ? simply because the Rover company no longer exists, so the government could not contact them to get confirmation of compatibility. However, Land-Rover does exist and confirmed that all its vehicles powered by Rover KV6 and K-series engines back to 1996 ? which used identical fuel rails, O-rings and fuel line technology to Rover cars ? are fully compatible. Owners of Rovers and MGs with those engines can therefore use E10 without fear.

What is the danger?

Some elastomers, plastics and composite materials used in pre-1996 car fuel systems are not compatible with petrol containing ethanol: it will gradually dissolve them. Cork, shellac, glassfibre-reinforced polyester and epoxy resins, nylon and polyurethane are on the ?unsuitable? list. Replacement with compatible materials is advised: paper, leather, Teflon, polyethylene and polypropylene are on the ?OK? list.

If any components in your fuel system are already old and deteriorating, ethanol will find them and accelerate the deterioration ? to the point where you could rapidly have running problems and even leaks that could start a fire. It?s also worth noting that some fuel tank lining products used in the past to coat the inside of pinholed fuel tanks are not compatible with ethanol and cases have been reported of these breaking down, leaking and blocking fuel lines. New lining products are available which are resistant to ethanol.

Long-term storage of ethanol petrol can lead to corrosion in metal parts of fuel systems, as the ethanol element can absorb moisture if left in the system for a long time, such as over winter, in a humid atmosphere. Historic vehicles are more susceptible to this than modern cars, as their fuel systems are vented to the atmosphere, not sealed. Additives are available to counteract this, from suppliers such as HCVA Founding Partner Classic Oils

So what can we do?
1. Avoidance

Fuels with lower ethanol content (labelled E5) are still available. The government has pledged to keep them available for five years and this dispensation is renewable, but availability will depend on demand. Fuel companies warn that if consumption falls below commercial levels they will no longer supply it. The only E5 fuels available are the higher octane ones ? 97 or 99 octane ? but this is not a problem as all petrol vehicles will run on them and, if properly adjusted, will run more efficiently on these fuels, counteracting to some extent their higher cost. If you shop around, the cost premium is not huge ? most supermarkets stock 97 octane E5, though sometimes only at one pump.

For older engines with 9:1 compression or higher, that were originally designed for 100 octane fuel, 99 octane fuels are available ? Tesco Momentum 99, Esso Synergy Supreme+ 99 and Shell V-Power 99 contain no more than 5% ethanol and Esso confirms that its 99 octane fuel is still ethanol-free except in Devon, Cornwall, North Wales, North England and Scotland. Using lower octane fuel in a 9:1 engine either requires retarding the ignition (which can lead to other issues) or the addition of an additive, which almost always works out more expensive than buying the 99 octane fuel if it can be found; some engines will accept 97 octane without complaint/adjustment, some won?t.

Additives are great for improving fuel, such as providing valve seat protection on engines with cast iron heads having soft valve seats, and for increasing octane. It?s much more difficult to make an additive to correct negative effects of something that is already in the fuel.

2. Additives

If additives are your preferred option, beware of the snake oil salesmen. Only buy from reputable businesses with an established history of serving the historic vehicle market. For example, tin pellets thrown in the petrol tank are NOT a cure-all for everything from unleaded fuel to E10.

Guy Lachlan of Classic Oils confirms that additives offering protection from the negative effects of ethanol in fuel will ONLY protect against corrosion from water absorbed by the fuel ? they will not protect against the harmful effects on incompatible materials in the fuel system.

3. Conversion
Converting your classic vehicle to tolerate E10 fuel will be the best long-term option for most owners doing higher mileages. Kits will soon be available, if they?re not already, for DIY conversion of popular classic vehicles and marque specialists are already well prepared to carry out conversions for you.

First, it is important to replace incompatible materials (listed above) in the fuel system: these will mostly be seals, hoses and gaskets. If you don?t do this, you may experience no problems, especially if your hoses, seals etc are relatively new ? but gradually they will deteriorate internally and begin to cause running problems as degraded materials are carried through the system, blocking jets etc. There is also a danger of ultimate failure of hoses and seals, causing fuel leaks.

Second, it may be necessary to re-route fuel lines away from engine hot-spots, as E10 (like most modern fuels) is more volatile than leaded petrol was and more prone to cause fuel vaporisation. This has become a major issue for some historic vehicles in the last decade. All modern vehicles have sealed fuel systems with fuel cooled by constantly circulating back to the tank, so fuel suppliers have allowed fuel volatility to increase dramatically. It is now at levels that vaporise far too easily in historic vehicles, where fuel may sit for some minutes in carburettor float chambers just above a hot exhaust pipe, when in traffic or stationary. Using E5 fuel, adding heat shields and re-routing and lagging fuel lines all help to reduce this problem.

Third, it may be necessary to richen the mixture fractionally, as the ethanol mix burns slightly leaner ? by 3.6%, so if your engine is set slightly rich already (as many are) there?s no need to alter it.

Add a clear plastic filter in the fuel line before the carburettors (ideally in a cool place where it will not increase vaporisation issues) and keep an eye on it, so that you will get advance warning of potential problems if rust or rubber particles are coming through from the tank and pump.

When touring, carry a spare fuel pump diaphragm and metal carburettor float(s) so that you can easily fit them at the roadside if problems arise.

Some suggest that fuel tanks should be replaced with ethanol-compatible tanks. While this would be sensible if you?re replacing the tank anyway, in reality replacement is only necessary if you have a tank made of glassfibre (as in some 1960s classic cars and motorcycles) or an incompatible plastic. Corrosion will take place inside a half-empty steel fuel tank whatever the fuel used if left standing for months in a humid atmosphere ? it is best to brim the tank before short-term storage and to use ethanol-free fuel if possible or at worst E5, with the anti-corrosion additive.

If you routinely store your vehicle for long periods such as over winter, fit a fuel tap between the fuel tank and the pump (if one is not already fitted). When storing the vehicle, run it with the tap switched off until all fuel in the carburettor(s) and pump is used up. This will reduce the risk of ethanol attacking rubbers in the pump and carbs, and will also avoid the hard residue left when modern fuels evaporate, which then blocks jets and requires laborious cleaning before the vehicle will run again after storage.

Another viewpoint on the same subject:

FBHVC LogoFBHVC clarification on E10 fuel usage and labelling for historic vehicles

After an extensive consultation process, the Department for Transport has introduced legislation to mandate E10 petrol as the standard 95-octane petrol grade from 1 September 2021 and in Northern Ireland, this will happen in early 2022. They will also require the higher-octane 97+ ?Super? grades to remain E5 to provide protection for owners of older vehicles. This product will be designated as the ?Protection? grade. The change in fuel applies to petrol only. Diesel fuel will not be changing.

Petrol pumps now show new labels designating the grade, the maximum ethanol content and an advisory cautionary notice. Other information regarding the introduction of E10 petrol may also be provided by fuel retailers such as the ?Know your Fuel? sticker (shown at the foot of this article).

For some time, service station pumps have had E5 and B7 labels consistent with the BS EN16942 standard that has been adopted across Europe. This standard also sets out the labelling requirements for other renewable fuel grades such as E85, B20, B30, etc. that can be found across Europe either on service station forecourts or for captive fleet use.

At the filling station

At the petrol station, a circular ?E10? or ?E5? label will be clearly visible on both the petrol dispenser and nozzle, making it easy for you to identify the correct petrol to use together with the warning text ?Suitable for most petrol vehicles: check before use?

Labels on modern vehicles
New vehicles manufactured from 2019 onwards should have an ?E10? and ?E5? label close to the filler cap showing the fuel(s) they can use.
What fuel should I use?

Almost all (95%) petrol-powered vehicles on the road today can use E10 petrol and all cars built since 2011 were required to be compatible.

If your petrol vehicle or equipment is not compatible with E10 fuel, you will still be able to use E5 by purchasing the ?super? grade (97+ octane) petrol from most filling stations.

Our recommendation

The Federation recommends that all vehicles produced before 2000 and some vehicles from the early 2000s that are considered non-compatible with E10 - should use the Super E5 Protection grade where the Ethanol content is limited to a maximum of 5%.

To check compatibility of vehicles produced since 2000, we recommend using the new online E10 compatibility checker: - Click Here - however, please note that many manufacturers are missing and there are some discrepancies regarding particular models.

Additional information on vehicle compatibility issues is available on the FBHVC website - Click Here -

What is ethanol?

Ethanol is an alcohol derived from plants, including sugar beet and wheat. Increasingly, waste products such as wood are also being used to manufacture ethanol. Therefore, it is renewable and not derived from fossil fuels.

Why are we using it?

Principally ethanol is being added to fuel in order to reduce carbon emissions as Britain heads towards its target of net zero emissions by 2050. According to Government experts, this will reduce greenhouse gases by 750,000 tonnes per year which, they say, is the equivalent output of 350,000 cars. The move will bring the UK in line with many European countries which have been using E10 fuels for a number of years already. In some parts of the world, such as South America much higher levels of bioethanol have been in use since as early as the 1970s.

What might happen?

Corrosion / Tarnishing of metal components Elastomer compatibility - swelling, shrinking and cracking of elastomers (seals and flexible pipes) and other unsuitable gasket materials Air/fuel ratio enleanment

Some historic vehicles use materials in the fuel systems that are damaged by ethanol. These include some cork, shellac, epoxy resins, nylon, polyurethane and glass-fibre reinforced polyesters. In later cars these have largely been replaced with paper gaskets, Teflon, polyethylene and polypropylene which are all unaffected by ethanol. Very old leather gaskets and seals are also resistant to ethanol.

As the ethanol molecule is smaller and more polar than conventional petrol components, there is a lower energy barrier for ethanol to diffuse into elastomer materials. When exposed to petrol/ethanol blends these materials will swell and soften, resulting in a weakening of the elastomer structure. On drying out they can shrink and crack resulting in fuel leaks.

If your fuel system has old hoses or any degradation of components, then ethanol may appear to advance these problems very quickly. You may experience leaks or fuel ?sweating? from fuel lines. Some fuel tank repair coatings have been found to breakdown and clog fuel systems, although there are plenty of ethanol resistant products on the market.

What can we do?

The most important thing is to ensure your fuel system components are regularly inspected and renewed as part of a routine maintenance programme for your historic vehicles. Ultimately owners should look to renew fuel system components such as hoses, seals and gaskets with ethanol safe versions as a long ? term solution and more of these are entering the market through specialists every day.

If you should decide to make the necessary vehicle fuel system modifications together with the addition of an aftermarket additive to operate your classic or historic vehicle on E10 petrol. The FBHVC strongly recommends that you regularly check the condition of the vehicle fuel system for elastomer and gasket material deterioration and metallic components such as fuel tanks, fuel lines and carburettors for corrosion. Some plastic components such as carburettor floats and fuel filter housings may be become discoloured over time. Plastic carburettor float buoyancy can also be affected by ethanol and carburettors should be checked to ensure that float levels are not adversely affected causing flooding and fuel leaks.

Ethanol is a good solvent and can remove historic fuel system deposits from fuel tanks and lines and it is advisable to check fuel filters regularly after the switch to E10 petrol as they may become blocked or restricted. If your vehicle is to be laid up for an extended period of time, it is recommended that the E10 petrol be replaced with ethanol free petrol which is available from some fuel suppliers. Do not leave fuel systems dry when storing, as this can result corrosion and the shrinking and cracking of elastomers and gaskets as they dry out.

Engine tuning.

Ethanol contains approximately 35% oxygen by weight and will therefore result in fuel mixture enleanment when blended into petrol. Petrol containing 10% ethanol for example, would result in a mixture-leaning effect equivalent to approximately 2.6%, which may be felt as a power loss, driveability issues (hesitations, flat spots, stalling), but also could contribute to slightly hotter running. Adjusting mixture strength (enrichment) to counter this problem is advised to maintain performance, driveability and protect the engine from overheating and knock at high loads.

Modern 3-way catalyst equipped vehicles do not require mixture adjustment to operate on E10 petrol because they are equipped with oxygen (lambda) sensors that detect lean operation and the engine management system automatically corrects the fuel mixture for optimum catalyst and vehicle operation.

Additives and vehicle storage.

Ethanol has increased acidity, conductivity and inorganic chloride content when compared to conventional petrol which is typically pH neutral. Ethanol can cause corrosion and tarnishing of metal components under certain conditions. These characteristics are controlled in the ethanol used to blend E5 and E10 European and UK petrol by the ethanol fuel specification BS EN15376 in order to help limit corrosion.

Some aftermarket ethanol compatibility additives claim complete protection for operating historic and classic vehicles on E10 petrol. The FBHVC is not aware of, or has tested any additives that claim complete fuel system protection with respect to elastomer and gasket materials for use with E10 petrol. The FBHVC therefore recommends that elastomer and gasket materials are replaced with ethanol compatible materials before operation on E10 petrol.

However, corrosion inhibitor additives can be very effective in controlling ethanol derived corrosion and are recommended to be added to ethanol in the BS EN15376 standard. It is not clear if corrosion inhibitors are universally added to ethanol for E5 and E10 blending so as an additional precaution it is recommended that aftermarket corrosion inhibitor additives are added to E5 and E10 petrol.

These aftermarket ethanol corrosion inhibitor additives often called ethanol compatibility additives are usually combined with a metallic valve recession additive (VSR) and sometimes an octane booster and have been found to provide good protection against metal corrosion in historic and classic vehicle fuel systems.

What happens if I fill up with E10 by accident?

Don?t panic ? your car will continue to run, just fill up with E5 at the next opportunity and avoid storing your vehicle for long periods with E10 fuel.

E5 Petrol

E5 petrol can contain between 0 and 5% by volume ethanol. Other oxygenated blend components may also be used up to a maximum petrol oxygen content of 2.7%. There is a variation at the pumps, not just between brands but also between different areas of the country, some will contain a lot less but the absolute maximum is capped at 5%.

E10 Petrol

E10 petrol contains between 5.5 ? 10% ethanol by volume. Other oxygenated blend components may also be used up to a maximum petrol oxygen content of 3.7%. Again, there is a variation at the pumps, not just between brands but also between different areas of the country, some will contain a lot less but the absolute maximum is capped at 10%.

It should be noted that some Super E5 Protection grade fuels do not contain Ethanol as the E5 designation is for fuels containing up to 5% Ethanol. To re-iterate, product availability varies by manufacturer and geographical location.