Randall-Reilly editor Jack Roberts works on an engine during a press event at Peterbilt's assembly plant.

Production of Paccar’s new 12.9-liter MX engine has begun at the new plant in Columbus, Miss., and Peterbilt trucks are being built with the engine.

Peterbilt has more than 1,500 certified technicians working at 674 dealers to handle the new engine business, said Todd Acker, director of marketing planning and communications.

Dealer technicians and sales personnel have been training at the Denton, Texas, Peterbilt plant. The company also brought trucking journalists to Denton this week to sample more than three hours of hands-on engine tear-downs.

The inline six-cylinder MX produces 1,750 lb. ft. peak torque and 380 to 485 horsepower. Among its features are compacted graphite iron engine block, integrated engine brake, a rear engine gear train, variable geometry turbo and a unit pump injection system.

The MX is designed for changing oil and oil filters every 40,000 miles and valve maintenance every 160,000 miles to minimize downtime, said Kelly Bender, training manager.