Discussion
I've been hearing rumours that the new ethanol based fuels can, like the cars that used only leaded and then had to use unleaded, cause substantial damage to some engines. This isn't apparently restricted to old cars but to modern euroboxes too I hear. Can anyone throw any more light on the matter?
And by sheer chance I got this email from Holden Vintage today.
The fact that all petrol now contains a small percentage of ethanol raises two very important issues
Ethanol is hydroscopic and this leads to separation of the ethanol and petrol with the ethanol going to the bottom of the tank/fuel pump/float chamber etc; and, ethanol is not compatible with a range of materials aluminium, brass, natural rubber, etc.
Shell UK have advised as follows
³The fuel we sell will continue to comply with the relevant fuel standards and specifications as it did previously. The finished petrol will meet the UK gasoline standard EN228, and the maximum amount of ethanol blended into the fuel will be in line with this and the RTFO (renewable fuel transport obligation - 5% max). However that doesn't really help owners of vintage vehicles. There are several things you can do to minimise the effects of ethanol. Firstly run a non-alcohol based fuel stabilizer all year round. As you say, older engines were designed primarily for straight gasoline, and using ethanol without protection may cause corrosion of some metals in the engine. It also may damage natural rubber and cork parts. Fuel Stabilizers contain additives to protect against rust and corrosion caused by ethanol fuel blends. If practical Install a water separation filter and fuel filter, and replace fuel lines, gaskets or o-rings with new ethanol resistant materials. Similarly replace the fuel tank if necessary with one made from an ethanol resistant material.
In terms of laying up the vehicle; Assuming the above measures are in place (we cannot make a laying up procedure if they are not, as it simply would not be advisable with fuel containing ethanol), we would suggest filling the fuel tank to about 95% of its capacity with fuel, rather than leaving the fuel tank low. This minimizes; the tank-breathing effect, the loss of volatile components and the ingress of moisture into the fuel tank. The latter in extreme cases can cause the appearance of free-water in the fuel.
If a fuel is to be stored in a motor vehicle fuel tank, then maintaining fuel quality is important in order to maintain good start-up and a good level of vehicle drivability. When an engine fails to start after a period of lay up, it may be less to do with fuel deterioration, and could be related to un-seasonal fuel, which may not be sufficiently volatile to start the engine from cold. Non volatile residues are often observed in the fuel tank, delivery system and/or carburettors in cases of severe evaporative loss of a gasoline. The residue can manifest itself as either a gum or lacquer-like film or deposit, or a gel-like substance. This residue would be a combination of low-volatility constituents and detergent additives that are found in gasoline, but concentrated after evaporation. We do not advise storing fuels in vehicles for more than 6 months. You should also take into account the differences between summer and winter grades of petrol. Petrol has a higher volatility in the winter in order to enable cold starting. For this reason it is better to fill the tank with a winter grade fuel (16th October - 14th April) rather than a summer grade.
The fact that all petrol now contains a small percentage of ethanol raises two very important issues
Ethanol is hydroscopic and this leads to separation of the ethanol and petrol with the ethanol going to the bottom of the tank/fuel pump/float chamber etc; and, ethanol is not compatible with a range of materials aluminium, brass, natural rubber, etc.
Shell UK have advised as follows
³The fuel we sell will continue to comply with the relevant fuel standards and specifications as it did previously. The finished petrol will meet the UK gasoline standard EN228, and the maximum amount of ethanol blended into the fuel will be in line with this and the RTFO (renewable fuel transport obligation - 5% max). However that doesn't really help owners of vintage vehicles. There are several things you can do to minimise the effects of ethanol. Firstly run a non-alcohol based fuel stabilizer all year round. As you say, older engines were designed primarily for straight gasoline, and using ethanol without protection may cause corrosion of some metals in the engine. It also may damage natural rubber and cork parts. Fuel Stabilizers contain additives to protect against rust and corrosion caused by ethanol fuel blends. If practical Install a water separation filter and fuel filter, and replace fuel lines, gaskets or o-rings with new ethanol resistant materials. Similarly replace the fuel tank if necessary with one made from an ethanol resistant material.
In terms of laying up the vehicle; Assuming the above measures are in place (we cannot make a laying up procedure if they are not, as it simply would not be advisable with fuel containing ethanol), we would suggest filling the fuel tank to about 95% of its capacity with fuel, rather than leaving the fuel tank low. This minimizes; the tank-breathing effect, the loss of volatile components and the ingress of moisture into the fuel tank. The latter in extreme cases can cause the appearance of free-water in the fuel.
If a fuel is to be stored in a motor vehicle fuel tank, then maintaining fuel quality is important in order to maintain good start-up and a good level of vehicle drivability. When an engine fails to start after a period of lay up, it may be less to do with fuel deterioration, and could be related to un-seasonal fuel, which may not be sufficiently volatile to start the engine from cold. Non volatile residues are often observed in the fuel tank, delivery system and/or carburettors in cases of severe evaporative loss of a gasoline. The residue can manifest itself as either a gum or lacquer-like film or deposit, or a gel-like substance. This residue would be a combination of low-volatility constituents and detergent additives that are found in gasoline, but concentrated after evaporation. We do not advise storing fuels in vehicles for more than 6 months. You should also take into account the differences between summer and winter grades of petrol. Petrol has a higher volatility in the winter in order to enable cold starting. For this reason it is better to fill the tank with a winter grade fuel (16th October - 14th April) rather than a summer grade.
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