THIONVILLE, France — It's been 20 years since Renault SA opened a piston manufacturing plant here in the northeast, just across the border from Germany and Luxembourg.

And in that time the plant has never shipped a bad piston. OK, it's surely produced a few bad pistons since 1981, but Daniel Preslier is proud to say that none of them has ever made it out of the plant door. Besides a bearing, can you think of any other engine component that takes such punishment? Not much room for mistakes.

Mr. Preslier is the chairman and managing director of the Societe Mosellane De Pistons SA plant in Thionville owned by Kolbenschmidt Pierburg AG.

The plant was built largely because the French government wanted to create jobs to replace those that were being lost in the steel industry at the time. Piston producer Kolbenschmidt acquired it in 1989. Kolbenschmidt and Pierburg would merge a decade later.

In April 2000, the plant cast its 100 millionth piston. For all of 2000, the plant's 370 employees produced 7.5 million pistons, mostly made of aluminum for passenger cars, but also alloy and steel units for trucks.

KP's worldwide piston sales dipped 3% in the first half of 2001 due to a downturn in U.S. business. But the Thionville plant has shown steady growth in revenues from €35 million ($32 million) in 1997 to €65 million ($59 million) last year. This growth has come largely due to the diversification of the plant's customer base. Besides Renault, Thionville now produces pistons for PSA Peugeot Citroen, Ford Motor Co. and Nissan Motor Co. Ltd.

The piston plant in Thionville is attached to another Kolbenschmidt Pierburg manufacturing facility where 383 employees produce oil, water and vacuum pumps (a total of 4.5 million last year), as well as complete modules. Like in the piston business, the customer base has expanded well beyond Renault to include Porsche AG, Volkswagen AG, Ford, Nissan and Adam Opel AG.

Sales for KP's air management and pumps division overall are up from €650 million ($592 million) in 1998 to €770 million ($700 million) last year. For the first half, sales for the division were €426 million ($388 million).