General Motors last night said it was spending over $230m on four of plants in the greater Flint, Michigan, area to "support" production of the 2011 Chevrolet Cruze and Volt, "representing" over 500 jobs.

The four plants are Flint Engine South, Flint Metal Centre, Flint Tool & Die and Grand Blanc Weld Tool Centre.

They are currently working on automated equipment and tooling for Cruze and Volt assembly, die development and stamping of body panels and other components, plus the manufacturing and assembly of key powertrain components including the 1.4-litre four-cylinder engine generator for the Volt and the 1.4-litre I4 turbo engine for the Cruze, GM said.

The Flint engine plant will produce 40 engines per day when production starts late next year and ramp up to 800 engines per day by the fall of 2011, GM officials told reporters.

The initial batch of Volt engines will be imported from a GM plant in Austria until the revamped Flint factory begins production.

"The Volt represents the next generation of high fuel efficiency vehicles," said GM manufacturing chief Larry Zahner. "We have to convince people this is an everyday car."

"These four GM manufacturing plants have a key role in GM's production of the next generation of fuel-efficient vehicles," he added.

Reuters noted that GM, which emerged from bankruptcy in July, was last year forced to scrap plans to build a new engine plant in Flint to produce I4 engines for the Cruze and the Volt as it struggled to conserve cash ahead of its eventual Chapter 11 bankruptcy restrucuring.

Both vehicles are now crucial to the 'new' GM's effort to reinvent itself to compete in the market for smaller and fuel efficient vehicles.

The Cruze, scheduled for US launch next spring as a 2011 model, is a GM Daewoo-designed model intended to be the brand's global compact car and - sourced from South Korea - is already on sale in the UK (since July) and Europe and, badged Holden, in Australia (from June).

While Europe gets 1.6- and 1.8-litre petrol and two-litre diesel engines and Holden takes just one of each, the US-built Cruze will get a 1.4-litre four-cylinder turbo engine expected to deliver better fuel economy than the current segment leader, the older Chevrolet Cobalt XFE, rated at 37 mpg highway.

The Volt, scheduled to start production in late 2010, also as a 2011 model, will be GM's first extended-range electric vehicle and can travel up to 40 miles on electricity from a single battery charge and has an overall range of about 300 miles with its flex fuel-powered 1.4-litre engine-generator which Flint South will make.

That plant previously made I5 and I6 petrol engines mainly for Chevrolet SUV models. Around 240 employees are working on re-tooling for the new I4 engines.

The Volt will be built at GM's Hamtramck, Michigan, plant. South Korea's Korea's LG Chem will supply battery cells which will be assembled into packs at a GM plant outside Detroit.

GM has said it plans to build 10,000 Volts in the first 12 months of production. The Volt will go on sale in late 2010.

A $1.7m spend on Flint Metal Centre will refurbish press lines to make sheet metal stampings for the Volt, representing 30 jobs.

Flint Tool and Die has designed dies for the Cruze and is now responsible for the construction and trial of stamping die sets for the Volt. About half this tooling was also designed at the facility.

Grand Blanc Weld Tool Centre will receive about $30m to build the robotic weld tool cells that will assemble the Volt body. About 250 employees are working on this project, including 60 who are installing the weld tool equipment at the assembly plant. The facility also built the robotic weld tool cells for the body shop to assemble the Cruze at Lordstown (Ohio) Assembly.

GM said the four manufacturing plants have also made significant progress in reducing their impact on the environment and now recycle over 97% of waste generated.

Materials recycled during the last year included 12 tons of batteries, 47,000 tons of scrap metal, 616 tons of oil, 229 tons of wood and 74 tons of plastic paper, GM said.