Western Europe is gearing up for the ''big shift'' - from leaded gasoline to unleaded. The United States has required lead-free fuel at the pump since July 1 , 1974.
In the last few weeks:
* A royal commission has urged that Britain require lead-free gasoline in all new cars by 1990 at the latest.
* West Germany suggested the introduction of lead-free fuel by Jan. 1, l986.
* The environment committee of the European Community has encouraged EC policymakers to rewrite existing legislation to permit lead-free fuel on the market in 1985. Current laws prohibit the Western European governments from forcing oil companies to sell lead-free fuel.
The momentum toward unleaded gasoline in Western Europe is causing widespread confusion and disagreement among automakers.
While West German carmaker BMW, headquartered in Munich, already is pressing for lead-free fuel, Stuttgart-based Daimler-Benz, firmly committed to the diesel engine, is unconvinced. Dr. Werner Breitschwerdt, head of research and development for Daimler-Benz, says requiring lead-free fuel would make cars more expensive to buy, maintain, and fuel. Even performance would suffer, he says.
Some carmakers say lead-free fuel will raise the price of a new car by $500 or more and use up to 10 percent more fuel.
Among European nations, France and Italy seem less eager to make the fuel switch, yet the move toward unleaded fuel appears unstoppable.
Sweden and Switzerland already have opted to tighten up on allowable emission levels from gasoline-fueled automobiles, thus pointing the way to lead-free fuel.
If Western Europe were to adopt the tougher American emissions standards for its cars, as it is urged to do, it would face a massive switch to catalytic converters. As a result, unleaded fuel would become mandatory, because the tetraethyl lead in leaded fuel destroys the effectiveness of the converter.
To be feasible in Western Europe, all nations of the area would have to adopt lead-free fuel at the same time. Otherwise, the free-flowing traffic across national borders would be hampered.
Even without catalytic converters, European carmakers have sharply reduced emissions of their products. Since 1972, for example, they have cut carbon-monoxide emissions by 30 percent and unburned hydrocarbons by 50 percent. Since 1977, nitrous oxide emissions have been reduced as well.
Whatever happens, the European manufacturers should have no trouble meeting the requirements of future laws.
Indeed, most carmakers have been shipping converter-equipped cars to the US since its unleaded-fuel law went into effect in 1974.
It's the customer, not the manufacturer, who'll have to pick up the tab.