Three decades ago, concerns about the shocking effects of lead upon public health prompted a rethink about the type of fuel we used to power our cars
“Unleaded fuel is now an inevitability – sooner or later, we will all be filling our cars with it,” Autocar wrote in its 11 January 1989 issue.
“For environmentalists – indeed, anyone even mildly green-conscious – the widespread use of unleaded cannot come enough.”
Petrol infused with Tetraethyllead was introduced in the early 1920s, having been found to reduce engine knocking. “It’s a convenient way of preventing pre-ignition,” our article explained, “or pinking – the metallic rattling sound from the engine when it is under load in a high gear. Pre-ignition doesn’t just sound nasty – if allowed to continue, it will burn out the pistons. Lead, too, has advantages; it lubricates the moving part of the upper cylinder.
«Leaded petrol reached a peak during the war, when the fighter aircraft engines needed maximum power and efficiency. Levels stayed high throughout the 1950s and 1960s, and lead’s importance increased with the growth in high-compression engines.”
By the start of the 1970s, the standard level stood at 0.84g per litre of petrol, steadily coming down to 0.40g/l by 1986, when a change in the law slashed it to 0.15g/l. Unleaded petrol is allowed to contain up to 0.013g/l.
“Lead is an extremely nasty pollutant – it can cause brain damage, particularly in children,” we said back in 1989, when the UK was pumping 3000 tonnes of the stuff into the atmosphere annually.
Indeed, studies had proven that raised lead levels in children’s blood had a direct link with brain damage, hypertension and learning disorders and that children who lived near motorways and town centres had a far higher likelihood of developing these illnesses.
A 1985 study in the US estimated that leaded petrol caused one million cases of hypertension per year and more than 5000 deaths from heart attacks, strokes, and other diseases related to blood pressure – and that was just for men aged between 40 and 59.
Something had to change, and fast.
Japan was the first country to introduce unleaded petrol in April 1972, and to ban leaded petrol, in 1986. In June of that year, unleaded petrol went on sale in the UK, and by 1988, it was available in 11% of filling stations. The first car to go on sale in the UK with an unleaded-only diet was the Toyota Celica GT-Four in 1987.
Meanwhile, the EU’s predecessor, the EEC, set new legislation for car emissions to make catalytic converters – which allowed engines to run only on unleaded – effectively essential by October 1993. This became known as the Euro 1 standard.
In the face of this new unleaded petrol, motorists were naturally worried – after all, lead was there for a reason.
“Around two-thirds of the 22 million cars and light commercial vehicles can accept unleaded fuel, according to the Society of Motor Manufacturers and Traders,” we explained at the time.
“There are, however, engines which simply cannot run on unleaded fuel. These are mostly older designs, with inlet and exhaust valves directed on a cast-iron cylinder head – and the lead is needed to lubricate the valves and valve-seats. Without it, they would deteriorate through corrosion and burning. To a lesser extent, very high-compression, highly tuned engines can’t be easily weaned of leaded fuel, either.
“In addition, there are power units that need modification in order to run on unleaded. A franchised dealer will tell you whether your car can be converted economically – or refer to the relevant Department of Transport booklet or a chart produced by CLEAR (the Campaign for Lead-Free Air).
“All that needs to be done is for the ignition timing to be retarded by a few degrees, thus causing combustion to occur fractionally earlier. Most dealers will charge £10-£20. On the other hand, dealers of prestige makes might charge up to £80 for turning an ignition chip around.
“Catalyst power units, though, are a different matter; these cannot accept leaded fuel under any circumstances, and damage will result unless unleaded is used.»
So, how easy would the switchover be?
Autocar explained: “After what must be regarded as a period of complacency, a lot of Rover Group cars cannot take unleaded – among them all Metros bar the 1.3GS, about half the Montego range, and all Maestros and Rover 216s. However, current valve-seat development will ensure that all models built after this spring will be able to accept it, with the exception of the MG Metro Turbo and Maestro Turbo.
Catalytic converters are universal now, but they were almost unknown to the British public in 1989.
“Contrary to widely held opinion, an engine tuned to run on unleaded fuel and an engine with a catalyst are not the same. Have your car retuned to use unleaded, and it won’t pump lead into the atmosphere, but it will continue to emit carbon monoxide, unburned petrol hydrocarbons and nitrogen oxides (NOx) – all poisonous. These gases produce smog and contribute significantly to the acid rain that is having such a dire effect on European forests. A catalyst engine, in contrast, produces an exhaust that’s free of these pollutants.
“When pioneered by the Americans in the late 1960s, catalysts were downright crude – and proved inefficient, lacking in power and thirsty. However, much has happened to them since. Today, ‘clean’ engines are much more efficient. Virtually all catalyst Porsche models have identical power to their non-catalyst counterparts.
“The modern catalyst is a stainless-steel box measuring about 12inx9in and containing a mineral combination over which the exhaust gases pass. Although …read more