State officials are warming up their engines on a $7.8 million plan to renovate and add to Grass Valley’s Department of Motor Vehicles facility. With the project’s environmental review period ending in September 2012, DMV officials garnered state Department of Finance approval in January to proceed to construction, said Jan Mendoza, a DMV spokeswoman. Built in 1971, the existing DMV facility is undersized and noncompliant with current California Building Codes, according to its initial project description. The DMV’s nearly 1.5-acre current site on Sutton Way off Brunswick Road is shared with the local California Highway Patrol’s field office, which occupies …