The main thrust of the new regulations, in the case of petrol, is the removal of lead, which has become more of a health issue in recent years. This wasn’t always so. Nitrous oxide and unburned hydrocarbon exhaust emissions, rather than lead, were originally seen as a pressing issue and catalytic exhaust systems were devised to reduce them. This spelled the beginning of the end for lead because, although it is a cost effective octane improver, it will dramatically shorten the life of the catalytic converter. Cars can’t tolerate leaded fuel because they use small amounts of platinum and sometimes rhodium and palladium spread very thinly over a large surface area in a ceramic monolith. Burning leaded petrol effectively results in this fine layer of noble metals being quickly coated or ¡§poisoned¡¨ by lead compounds. Another factor is that, in the absence of lead, many manufacturers have developed engine components such as piston sealing rings that can be degraded in the presence of leaded fuel combustion.
Now that lead has come to be recognised as a more serious poison to humans ¡V especially children ¡V it has to go. Of course, that is not the only reason. With leaded petrol consumption declining, it is also becoming increasingly expensive to maintain special leaded pumping, storage and transport facilities around the country.
While unleaded fuel is more expensive to produce than leaded fuel, the upside is that unleaded engines run cleaner, allowing longer service intervals and longer spark plug life.
Our comment on the changes
Many people are concerned about the effects of eliminating leaded fuel, but in most cases these concerns are unwarranted. We say this because the quantities of leaded fuel being sold at present (about 57 per cent) indicate that the vast majority of motorists who buy leaded fuel do so not because their engines need it, but because they’ve not been informed correctly. Information will be available from a Naamsa website (www.naamsa.co.za) as well as the petroleum industry website (www.sapia.co.za). In addition, the information should be available in printed form on most forecourts.
– If your vehicle was built from 1997 onwards you should use the appropriate ULP grade. At the coast this will usually mean that you’ll have to use 95 RON, unless your owner’s handbook specifies otherwise. Inland, most engines are quite happy on 93 RON even if the owner’s handbook specifies 95 because the increase in altitude compensates for a two-digit loss in RON number, according to research conducted by the Centre for Automotive Engineering, a world-class research organisation in Atlantis, Cape Town.
If your owner’s handbook specifies an octane number higher than 95, then you should consult the manufacturer. Engines with electronic knock sensing and control are usually safe when operated on octane ratings as low as 91, albeit with a small loss in performance during full throttle running. Engines whose ignition timing is controlled mechanically would in some cases need a reduction in spark timing.
– If your vehicle was built before 1997, you should consult your owner’s handbook, the manufacturer’s website or the other websites mentioned above. Most of these engines, especially the ones with aluminium cylinder heads, should be able to run on ULP, but if your engine is not compatible with ULP you’ll have to use LRP. This fuel is suitable for practically all older engines.
– In general, motorbikes, lawnmowers and outboard engines are compatible with ULP, except for some older models. If in doubt, consult the manufacturer, or use LRP.
– Some oil companies will also market a fuel additive that will protect cylinder head valve seats. This should be added to ULP in the proportion shown on the container, but only if your engine is not compatible with ULP, and you still want to use ULP. There is no benefit in using a larger proportion or using it in combination with LRP. It should also not be used if your engine is fitted with a catalytic converter, because it may damage the converter. There will be a number of bogus products on the market, so stick to reputable brands.
The worst-case scenario
If, for whatever reason, you’re using a fuel that you suspect will lead to valve seat recession, then keep in mind that this condition usually occurs during prolonged running at more than 60 per cent throttle opening. The valves will overheat, causing pitting and (eventually) uneven idling. However, if you use your car mainly in town, and seldom use more than half-throttle on the open road, you may never experience any seat recession.
The cure is to have hardened valve seats fitted, not immediately, but only if and when pitting occurs.
How safe is LRP?
The fact that most lead replacement fuels contain MMT (a manganese compound), potassium or phosphorous has been noted with concern by organisations that want all metals banned from fuel. However, the amount of these compounds in LRP is far less than the amount of lead compounds in leaded fuels. In addition, this fuel will only be needed in older vehicles that are not fitted with catalysts, so these items cannot be damaged. Sapia, the mouthpiece of the oil industry, has estimated that only five per cent of vehicles on our roads would need LRP.
Benefits of using unleaded fuel
Many motorists are under the impression that ULP is only of some benefit if the car is fitted with a catalytic converter. This is not true. The elimination of lead results in fewer deposits clogging up the oil and settling on the spark plugs, thus reducing maintenance costs. In fact, a spark plug life of over 100 000 km is quite common when platinum plugs are fitted.
Black exhaust tailpipe myth
There is an erroneous belief that the changeover to unleaded fuels is not good for the vehicle due to the black colour of the exhaust tailpipe. Leaded fuel is viewed as superior in view of the grey tailpipe, which is associated with good performance and supposedly indicates that the engine is in good condition. This is simply not true, because the grey colour is due to the presence of lead oxides. Removal of lead means no lead oxide formation and thus a darker tailpipe.
Low sulphur benefits
Diesel engines will benefit from the lower sulphur content available from the start of the new year. The sulphur occurs naturally in the crude oil that diesel fuel is produced from, and besides polluting engine oil it also combines with combustion by-products to form acid. Reducing the sulphur content to low levels is expensive but modern engine design increasingly demands it.
The major benefit of low sulphur will be a lengthening in oil change intervals, and a reduction in engine wear. You can therefore expect manufacturers to introduce longer service schedules once the old fuel is completely phased out. There will also be a reduction in noxious gases issuing from the exhaust.
Diesel fuel lubricity
The sulphur in the fuel acts as a lubricant for the pump and injectors, so a reduction in sulphur implies a reduction in lubricity. This is only one of the reasons why mixing diesel fuel and paraffin, which contains very little sulphur, leads to pump and injector damage. The new lubricity specification will take care of this, because the oil companies will add compounds that increase the lubricity. In any case, the oil companies have been following their own lubricity specifications up to now, so lubricity problems only arise when the fuel mix has been tampered with.
The new fuel regulations had not been finalised by the time we went to press, but they’re expected to be along these lines:
= Lead will no longer be blended into any petrol, so the marketing of leaded petrol will cease.
= The government will permit the countrywide marketing of 91, 93 and 95 RON metal-free unleaded petrol (ULP). RON is short for Òresearch octane numberÓ a measure of a fuel’s low-speed knock properties.
= All three grades will not be available everywhere. Instead, market demand will guide the oil companies to decide which grade to market in each area. Nevertheless, Naamsa (National Association of Automobile Manufacturers of SA) expects, perhaps somewhat hopefully, that motorists will be able to find the correct fuel for their engine in all areas.
= The introduction of LRP (lead replacement petrol) with RON ratings of 93 inland (more than about 1 200 metres above sea level) and 95 at the coast will cater for older vehicles that are not designed for unleaded fuel. This will also be supplied according to market demand, at the same price as the equivalent grade of ULP. LRP may contain metal compounds, as long as they are not lead.
= The use of 95 RON in inland areas, where more than 99 per cent of engines are happy on 93 RON, will be discouraged, by the introduction of a (inland only) demand managed levy of at least ten cents per litre. The reason for this is the need to avoid additional costs to the country as a whole because the production of grades higher than actually needed will strain refinery capacity and reduce foreign currency reserves.
= Diesel fuel will be considerably improved by the introduction of a new premium grade containing only 50-ppm (parts per million) sulphur, while the present premium grade containing 500-ppm sulphur will become the new standard grade. The present standard grade containing 3 000-ppm sulphur will no longer be available. A lubricity specification, which has been absent until now, will also come into effect for all diesel fuel.
