E10 Myth & Fact
Understand what E10 fuel is, how it might affect the way you look after your classic and why there is so much nonsense and scare mongering about it.
What is it?
E10 fuel has been in both the classic and mainstream press a lot. Pump fuel is made up from an awful lot more than just fractionally distilled mineral oil, part of that is ethanol. Currently the UK standard for ethanol content in normal unleaded fuel is less than 5%, so at the time of writing it is labeled as E5. Ethanol is a fuel produced from crops, by using it we reduce the carbon footprint of every tankfull. The government is keen to increase the amount of ethanol in our fuel because it decreases our dependence on OPEC nations and it could reduce the national CO2 emissions by 750,000 tonnes a year. In September 2021 the UK standard for ethanol content will increase to 10% on standard unleaded, but will remain at less than 5% for super or premium unleaded.
What is the issue with a higher ethanol content?
Firstly, there is nothing we can do about it. Legislation is passed, so there is no use puffing your chest out and getting all annoyed with the establishment. Secondly, super or premium unleaded will continue for a minimum of the next 5 years, so as long as you fill up with that everything stays the same. Thirdly the odd tank full will make no difference if you can’t find premium. Any issues that may occur are from long term use or storage. However, there are a couple of issues with Ethanol, so let’s look at them one by one and see what you can do to mitigate any issues.
Water
Ethanol is hygroscopic, which means that it attracts moisture from the atmosphere. The water separates in the fuel mix and then corrodes anything ferrious. This means the inside of steel fuel tanks, carb pots and steel fuel lines. The rust particles break off, get swirled around your fuel system and then block up in your fuel filter, carburettor or injection unit. It is a particular problem for classic cars, because we don’t use them all the time and therefore the fuel has more time to absorb water. The average classic does less than 1000 miles a year, which means that they use less than 50 gallons of fuel. The average modern car uses about 350 gallons a year which means the fuel inside is 7 times newer and has no time to absorb the water. Now this has been a problem for years, it is just going to get a little worse, so what can you do?
- Keep you fuel fresh – Try to use the fuel you put in the car within two months
- Install an inline filter at the tank and carburettor end to catch any debris
- Change fuel filters every year as part of your regular maintenance
- Don’t store the car with full tanks over the winter
- Store your car in an environment with low humidity, around 45 to 60% is about perfect
- There are fuel preservers on the market you can add to mitigate these issues when storing a car
Density
The density and calorific value of E10 fuel will be different from E5. In the same way as you get a difference in performance running regular or super unleaded fuel there will be a difference between E5 and E10. If you are going to use E10 fuel all the time then you may well need to adjust the fuel/air ratio or the timing of the engine to suit. Your engine will probably run lean, but well within the parameters of being able to adjust the difference out. Our advice is that when you come in for a regular service, have whatever fuel you are most likely to use in the car. That way, when the mechanic tunes it up, he is doing so using the ‘right fuel’.
Ethanol Is Corrosive to Some Rubber Components
This is a fact, but we have had Ethanol in our fuel for donkey’s years, Europe have had E10 for a decade and the Americans have been using E85 since the 1960’s. So it is not a new phenomenon. Rubber hoses perish over time and are almost always overlooked when it comes to maintaining a classic. It is the same with tyres. 50% of all the vehicles we see in the workshop have 20 year old rock hard tyres, with perfect tread depth. They look OK, but are way more likely to fail and have because they flex less and crack as they move about or are put under pressure.
Rubber Fuel Line
There actually isn’t much rubber in any fuel system. Generally there is a flexible pipe from the fuel tank/pump to a ‘hard line’ that runs up to the engine bay, from there there are a few sections of rubber pipe that run from the hard line to the regulator and onto the carbs. If you can do it yourself, the new E10 approved flexible fuel line will cost less than 15 quid for 2 meters in any Auto Factors in the country and a couple of hours on a weekend. Alternatively, we can do this for you for about £150 + VAT
Rubber ‘O’ Rings
There are rubber ‘o’ or sealing rings in both carburettor and injection cars. They are way more likely to fail because they are 20 plus years old than simply down to another 5% of ethanol in the fuel. As part of your maintenance, keep an eye and nose on the fuel delivery components in your engine bay. If you can smell fuel, you have vapour present and therefore the beginnings of a leak. It needs to be tracked down and repaired. New old stock carb and injection kits should be avoided like the plague. The rubber is old, and although they might look OK are probably no better than the ones you are taking off.
Project Shop Rebuild Carbs and Injection Systems
We can strip and rebuild both carburettors and injection systems. We will not only make them safe, but doing so will also improve your performance and fuel consumption. Carburettor rebuilds start from £250. Get in contact for a quote.