The auto industry is on fire and John Stewart is standing by, prepared to extinguish and salvage parts of it.

Stewart, a former manager at Toyota's big auto assembly plant in Georgetown, Ky., has been quietly buying up distressed plants and companies over the past few years as a private equity investor with a strategy.

Last week, Stewart struck boldly: Grouper Holdings, a subsidiary of the investment company he co-founded, MiddleGround Capital, stepped in with $218 million in cash to buy the assets of Shiloh Industries of Valley City, Ohio. Shiloh is a multi-factory mainstay of U.S. metal stamping, aluminum parts and carbon fiber that has been making a name marketing itself as a "supplier of lightweighting."