24th July 2020

New E10 petrol may mean classics will "run better"

In an effort to reduce carbon emissions to net-zero by 2050, the Government have stated their intention to move to the E10 grade of petrol - which they estimate could save around 750,000 tonnes of CO2 per year.

However, many classic car and bike owners will have heard and read the news stories about the potential damage their vehicles could sustain through the use of E10 fuel. At Footman James, we've been closely following the story and recently updated our article on E10 following the Department of Transport's (DfT) consultation period.

According to the DfT, potential issues of using E10 fuel in your classic can include:

  • Blocked fuel filters
  • Damaged fuel pumps
  • Degradation to flexible fuel hoses
  • Corroded carburettors

Despite this, Paul Ireland, author of Classic Engines: Modern Fuel, suggests that classic engines may actually run better using ethanol-blended fuel.

Speaking to Express.co.uk, Paul said: “There’s not a lot of evidence for ethanol causing problems with cars running [alcohol fuel]. All of the tests were really focused on the practical problems, not the theoretical problems. We’ve found with the classic engines, carburettor engines run a lot better on fuel that has ethanol in and there are various reasons for that. In other words, ethanol petrol engines run better and because they run better they are actually less likely to do themselves damage. One of the problems that modern petrol causes is this phenomena called cyclic variability. And what this does is it can damage your engine when it's just running along.”

Cyclic variability causes cylinder pressures to scatter and in severe cases can cause fuel to burn or misfire.

Paul adds: "The thing to remember is ethanol petrol and alcohol in petrol is not new. It was originally launched in a fuel called Cleveland Discol, I think it was around in the 1930s."

“If you think about it, those cars although they were the new cars of the day, they are the classic cars of today and they were running on ethanol-blended petrol without any problems at all."

“The problem with ethanol-blended fuel is a lot of the things people are sayings are factually correct but they are not what the real problem is...Ethanol in petrol, it reduces cyclic variability, the engines run better on it so it is actually doing less damage to themselves when they are running.”

Paul does concede though that, as with all modern fuels, E10 is not problem-free. But rather than being a worry for classic owners, some care, maintenance and a few low-cost solutions can mean that you get the best out of using E10 fuel. You can read more about Paul's research on this topic on the MGT Society website.

In contrast, Martin Greaves of Classic Performance Engineering is concerned about the use of E10 in classic vehicles. He states, "In the industry, we are already seeing problems arising from the current addition of low levels of ethanol in existing fuels (even up to the 5% level). These problems include deposits blocking fine-mesh fuel filters, degradation of fuel pipes and hoses and internals of carburettors suffering corrosion.

The regime required to fully empty and clean fuel systems between uses of the car is prohibitive both in terms of time and practicality, and replacing components with ethanol compatible ones may not always be economical, or in certain cases, even possible.”

If you're happy with how your vehicle is running on E5 petrol at the moment, you need not worry about the change to E10. The Government has pledged that supplies of E5 as a protection grade will continue alongside E10.

Will you be using E10 in your classic when it goes on sale? Let us know your thoughts in the comments below!

The information contained in this blog post is based on sources that we believe are reliable and should be understood as general information only. It is not intended to be taken as advice with respect to any specific or individual situation and cannot be relied upon as such.

I have owned a 1992 Mercedes 190e 1.8 saloon for the past 9 years which has covered only 120,000 miles from new with full documented service history, which fuel would you recommend me to use as it is rather confusing unlike the earlier years one could have the choice of 3 star, 4 star or 5 star plus. Your comments would be most appreciated. Kind regards John

Camdenjohn, 29/07/2020

I have always approached this subject with an open mind with the tooing and froing in the arguments, but as I run older cars and motorcycles I can only comment on my personal experiences not theory. One of my cars had almost no compression when returning from a trip to London, upon strip down number 1 piston had burnt the whole top of the piston off. I now run my car on super unleaded which makes it pull much better and smoother. My old bikes have had the carbs changed along with new fuel pipes, but I noticed a slight leak from one of the petrol tapes which left a brown varnish like substance down the side and onto he crank cases, this never used to happen before. Mowers carbs block up between seasons with this varnish, I know the apparent way to solve is to drain all petrol from the fuel system which verges of impracticable on an ongoing process as you end up with an ever increasing storage problem. As far as no drop off in MPG, I ask how is it that to overcome the increased oxygen in E5/E10 which weakens the mixture, you have to increase the fueling makes this so? surely the more you put in for the same result the MPG drops (it's not logical).

johnnyboy, 29/07/2020

My father would only ever use Cleveland Discol in his Standard 10, then his Triumph Heralds. I remember that it was advertised as the only petrol with alcohol. He got very annoyed when Cleveland disappeared in, I believe, the late sixties. I don't know if I'll use E10 in my Triumph 1500. I use a minimum of 97 octane at the moment. Mind you, the car has only done twenty miles in the last six months since I got it roadworthy, and now it's a rolling restoration. I have read all all the horror stories of the effects of E10 on components but who do you believe?

shyboy, 29/07/2020