HLR Badge Historic Lotus Register News
Home News The Cars Membership Events Links For Sale
Introduction of E10 Petrol

The Federation of British Historic Vehicle Clubs (FBHVC) has issued a Press Release, which members might find useful to read, regarding the introduction of E10 petrol and its use in classic cars.

The full article is available on the FBHVC website here, or can be downloaded here. Parts of it are reproduced below.

After an extensive consultation process, the Department for Transport has introduced legislation to mandate E10 petrol as the standard 95-octane petrol grade in Great Britain from 1 September 2021 (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. 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%.

Fuel Systems

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.

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.

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.

Castle Combe Autumn Classic

The Castle Combe Autumn Classic will be held on Saturday 2nd October. This is always a good race meeting, and several HLR members will be competing. A display area for HLR cars has been arranged - details can be seen in the Members' Area here

Classic Motor Show - NEC Birmingham, 12-14 November

The Lancaster Insurance Classic Motor Show, with Discovery, which brings together a great array of classic car and motorcycle clubs along with their iconic classic and vintage cars and motorbikes, will take pace on 12-14th November 2021 at the NEC, Birmingham, UK. HLR Members can take advantage of a discounted entry, using the code on the Members' Classic Motor Show page here, so, if you aren't currently a member, here's an incentive to join! Please note that discounted entry is only available on pre-purchased tickets, which must be booked before midnight on Thursday 11 November 2021.

John Frayling

John Frayling passed away on Wednesday 19th May 2021. John was heavily involved in the production of the Elite, having joined Lotus from the Ford styling department at Dagenham. His first job was to sculpt the one-fifth scale model of Peter Kirwan-Taylor's design, translating the drawings into a three-dimensional shape. He then constructed the full-size model in plaster of Paris that was used to produce the first set of moulds, from which the Earl's Court prototype was produced. The model and the first few cars were built in a decrepit building in Edmonton, John often working alone for many hours. The building was later used by Cosworth. As the car was developed for production, John worked with Maximar modifying the moulds to simplify manufacture, reducing the number of mouldings from the sixty used for the Earl's Court car, to three. John later went on to design the bodywork of the Lola MkVI GT (which evolved into the Ford GT40) and the Lola T70 Mk I. John also worked on the Elan Coupe and the Europa, eventually leaving Lotus to produce the short-lived Clan Crusader.

John Frayling


The Consultation document will be available to download once it has been emailed to members.