West Los Angeles private equity firm Gores Group announced Tuesday that it has made an equity investment in Clinton Township, Mich. automotive publishing company Tweddle Group Inc.

Tweddle produces informational materials for cars such as owner’s manuals, dealer directories and maintenance guides in both print and video form. Its customers include BMW, Ford, Toyota and Chrysler. The third-generation family business was founded in 1954.

Gores Group also plans to take an operational role alongside the company’s management team with the goal of growing the business.

Terms of the transaction were not disclosed.

“The Gores Group will be an ideal partner as we continue to move our business forward, expanding geographically, across additional original equipment manufacturers, and into new technologies,” said Andy Tweddle, chief executive of Tweddle.

Gores Group was founded in 1987 by Alec Gores, No. 22 on the Business Journal’s list of Wealthiest Angelenos, with an estimated net worth of $2.65 billion. The firm manages about $3.6 billion in assets and has offices in Los Angeles, Boulder, Colo. and London. It is currently building a new headquarters in Beverly Hills.