Motor City is about to restart its economic engine, at least if its lawyers get their way. The bankrupt city of Detroit is expected to file the long-awaited blueprint for its ground-breaking Chapter 9 municipal bankruptcy — the biggest ever by a U.S. city — on Friday, as the city moves grapples with its crippling debts. Kevyn Orr, the city's state-appointed emergency manager, said his office will file the city's plan of adjustment in federal court then, ahead of a March 1 deadline. That plan will spell out how the city plans to tackle its mountain of $18 billion in debts — and it is sure to face objections and legal challenges from creditors, some of whom could get as little as 20 cents on the dollar, the Detroit Free Press reported Thursday. A draft of the plan given to creditors last month showed retirees and pensioners would get $4.3 billion in payments and bondholders about $1.1 billion over the next 40 years.