General Motors Corp. has scrapped plans to build a new plant to produce engines for its Chevrolet Volt extended-range electric vehicle and instead will build the engines in an existing Flint factory.

The move will save money and use available floor space within the Flint South engine plant on Bristol Road, the automaker announced Tuesday.

GM had said in September it would invest $370 million in a new 552,000-square-foot manufacturing plant that would produce four-cylinder engines for the Volt and the Chevrolet Cruze small car. But in December, the automaker announced it was delaying construction to conserve cash as it sought federal loans.

Instead, GM will spend $250 million installing new machinery and equipment at Flint South.

Preparation work will start this spring and engine production is expected to start in December 2010.

That's about one month later than when GM said the Volt would reach showrooms, but the automaker has said it could build the engines in other facilities and ship them to Michigan.

The new engines include a 1.4-liter turbo engine for the Cruze and a 1.4-liter naturally aspirated engine for the Volt.

The Volt will rely on a lithium-ion battery pack that will let commuters travel up to 40 miles on electric power alone. The Volt's engine kicks in after its battery is drained by about 70 percent to sustain the battery's remaining charge to keep the car running for several hundred miles.

The four-cylinder engines are part of an approach by GM to double global production of small four-cylinder engines by 2011.

GM has said a third of all its engines made in North America in 2011 will be four-cylinder and 21 percent of those will be turbocharged -- seven times the number of four-cylinder turbo engines made today.