Rockwell to Sell Automotive Unit : Manufacturing: A competitor will buy three plants that employ 1,722 workers making plastic parts for cars.

Rockwell International Corp. said Monday that it will sell its automotive plastics business to a subsidiary of competitor Cambridge Industries Inc. for an undisclosed price.

Rockwell agreed to sell three automotive plastics manufacturing plants to Plastics Acquisition Corp., a unit of Cambridge Industries, an automotive plastics firm in Dearborn, Mich. The deal is subject to regulatory approval.

Rockwell will shed about 1,722 employees who will go to work for Cambridge. Of those, 1,150 now work at a plant in Centralia, Ill., 367 in Lenoir, N.C. and 185 in Newton, N.C. About 20 sales and engineering employees working at Rockwell’s Automotive headquarters in Troy, Mich., would also work for Cambridge. After the sale, Rockwell would have 73,300 employees, including 6,700 in Orange County.

Peter Aseritis, an analyst for investment bank First Boston Corp. in New York, said he estimated the division will sell for between $200 million and $250 million.

“From Rockwell’s point of view, (with $11 billion in sales), it doesn’t appear to have a big impact on their earnings,” he said.

Don H. Davis Jr., Rockwell’s chief operating officer, said the deal is in accord with Rockwell’s strategy of emphasizing its manufacture of automotive components and electronics parts, which the company can put together and sell as complete component systems, such as car seats, sunroofs or door latches.

The automotive plastics unit made parts such as the hood for the Dodge Viper.

Davis, who declined to comment on Aseritis’ estimates, said the division was profitable with annual sales of about $200 million.