One question which always niggles me. In the late 60's and 70's I ran my motorbikes and cars on Cleveland Discol which was a petrol alcohol mix available widely in the UK.

See https://www.youtube.com/watch?v=4uEqqlqqf4Q

Never had any problems with that. What's the difference with the new E10 fuels. Are alcohol's properties different to the ethanol used in E10 fuel?

I have heard it is possible to remove the ethanol from the petrol by adding water. Is this recommended?

I would strongly recommend against removing ethanol from petrol.

It is easy to remove just by adding water and waiting for the ware to settle. However, there are three serious issues:

1. &Ethanol is an anti-knock additive. Removing it from the petrol reduces its RON and may make engines susceptible to pinking or knocking.
2. The physical properties of petrol are defined by various international standards, one is its specific gravity. Removing ethanol will change the specific gravity of the petrol and as a result carburettors, etc. will not deliver the correct mixture.
3. Water that has come into contact with ethanol blended petrol is HIGHLY corrosive. If water has been used to remove the ethanol, unless the resultant petrol is properly dried to remove ALL traces of water, it may cause significant damage to fuel systems.

It’s a lot easier and safer just to replace the rubber hoses, etc.

There's an archive article from Motor Sport magazine online, dated 1934, concerning the introduction of Cleveland Discol. This states that the fuel contained 25% alcohol (ie. same as is currently used in Brazil). It evidently didn't cause too much damage as it remained on sale well into the sixties (I can remember it).

The anecdotal evidence concerning damage from E5 fuel seems to relate largely to plastics - which either wouldn't have been in use back then, or presumably wouldn't have had the same composition. This probably means that fuel lines and carb 'O' rings will need replacing with ethanol-proof versions. Not a huge problem. Motorcyclists also report that glassfibre fuel tanks are disintegrating, which is far more worrying. However; grp tanks were banned (for new bikes) many years ago. Therefore survivors are now getting quite old, and grp deteriorates over time anyway. So this could be an exacerbation of a pre-existing condition - fuel getting into the laid-up material once the inner gel-coat surface is breached - with ethanol possibly speeding up the process.

Metalllic corrosion, as you have pointed out elsewhere, is linked to water contamination. That is also worrying (particularly for vehicles that aren't used regularly) since there's always going to be some condensation within a fuel tank. Keeping the tank full might help, along with a suitable additive to maintain fuel condition during storage (such additives have been used in the marine world for a long time). Incidentally; all modern petrol seems to store poorly (a month or so seems to be the recommended limit), but is it true that fuel containing ethanol is even worse because it tends to separate out?

I really welcome this sensible discussion, without the hysteria that has accompanied it in certain quarters.

David,

Thanks for the comment, unfortunately the press appears to prefer sensationalism rather than fact when it comes to E10.

Just one point on your comment. You suggest Cleveland DIscol contained 25% ethanol. I find this surprising.

There is one issue with ethanol blended fuel. It causes enleanment. As the alcohol contains oxygen, you are getting too much oxygen and not enough hydrogen and carbon. You need a richer mixture to compensate.

At Manchester we found that using E5 was within the normal tuning tolerances, i.e. you could swap between normal petrol and E5 without having to retune the engine. E10 required the mixture to be made richer at higher RPM / loads by about 2-3 flats or 1/4 to 1/2 turn on the adjusting screw on the SU carb.

The comments from Brazil using E25 stated they needed richer needle to offset the enleanment effect.

Given that Cleveland Discol was intended for use in "normal" cars without the need to retune them, I would be surprised if it had more than 75 or 8% alcohol content.

I agree that 25% does sound like a very high alcohol content for ordinary road use. The info, as I said, came from Motor Sport magazine, (March 1934 issue, announcing countrywide availability of Discol in an article titled "Alcohol Fuel For High Compression Engines"). It says that Cleveland was one of two firms offering fuel with alcohol-based anti-knock content - the other was 'Koolmotor Alcohol Blend', which had been on sale since early 1932. Cleveland was the third largest motor fuel distributor at that time, and Koolmotor had "some hundreds" of pumps across 27 counties. Both firms used alcohol from Distillers Group.

The article mentions the percentage of alcohol in order to explain how an alcohol blend could be sold at the same price as normal premium petrol: "for every gallon of alcohol fuel manufactured, only 75% of it (the alcohol content is roughly 25%) is subject to ... petrol tax." (Industrial alcohol wasn't taxed.) This 25% figure presumably applied to both Koolmotor and Discol since they cost exactly the same.

The article doesn't mention any need for re-jetting - and as Koolmotor had been in use for two years, any 'over lean' issues should have been common knowledge by then. Perhaps Motor Sport got the figure wrong? Yet their taxation-versus-costs argument sounds convincing...