DaytonDailyNews.com

MORAINE — Years ago, diesel enthusiasts criticized General Motors Corp. and Isuzu for using aluminum in the diesel engines they make.

The critics argued that aluminum wouldn't meet high production demands.

That was then. As the DMAX engine plant off Dryden Road gears up to celebrate production of its 1 millionth Duramax V-8 turbo-diesel engine today, the critics are silent.

The milestone will be marked with a celebration expected to draw John Buttermore, GM powertrain vice president of global manufacturing; Naotoshi Tsutsumi, director and senior executive officer, Isuzu Motors Manufacturing Division; and Jim Clark, president of the International Union of Electronic Workers-Communication Workers of America, among others.

The celebration at the plant is not open to the public. But like the nearby GM Moraine Assembly plant — which celebrated production of its 6 millionth vehicle in January — the event marks a bright spot in an area where large manufacturers are too often troubled.

"I just think it shows you how good they really are over there. When you get 1 million motors and counting, that's a lot of work," said Willie Thorpe, chairman of the IUE-CWA's Automotive Conference Board.

"Production of the 1 millionth Duramax diesel engine at DMAX is a significant achievement that not only highlights the strength of the product in the marketplace, but also the success of the partnership between General Motors, Isuzu Motors and the IUE-CWA," Maho Mitsuya, DMAX chief executive, said in a statement.

The 584,000-square-foot plant has 1,225 hourly and salaried employees and produces 200,000 engines annually. The joint venture was established in 1998.

Vehicles with 2007 Duramax engine

Chevrolet Silverado HD: 365 horsepower

GMC Sierra HD: 365 horsepower

Chevrolet Kodiak Medium Duty: 330 horsepower

Chevrolet Express: 250 horsepower