The Mack E7 460 engine delivers impressive power, especially when handling heavy loads exceeding 90,000 lbs. gross. It performs similarly to a 12.7 Detroit, preferring higher RPMs, ideally around 1600 for cruising. Power drops significantly below 1400 RPM; the 427 and lower horsepower variants offer a more favorable torque curve. Despite its power, the E7 460 is a relatively light engine, contributing to good fuel mileage and allowing for some load transfer to the steer axle.
For optimal performance with the 460, a 13 or 18-speed transmission is recommended, paired with gearing that allows for 1500 RPM at cruising speed. When operated within its preferred RPM range, the E7 460 pulls strong, keeping pace with 500 hp C15 engines. While 550 hp engines might outperform it on steep inclines with similar loads, the difference isn’t substantial. (Note: ECM tuning could influence performance.)
One downside is the reliance on Mack dealerships for parts. While parts personnel are generally knowledgeable, inventory for older engines like the E7 460 can be limited, potentially leading to delays. Experiences with Mack service departments can vary; in one instance, multiple visits were required to rectify issues stemming from initial repairs.
Rebuilt Mack E7 engines sometimes come with a 3-year unlimited mileage warranty, particularly if injectors and turbochargers were replaced during the rebuild. Depending on the installation date, the engine in question might still be covered.
The Jake brake performance is considered somewhat weak, but this is typical for a 12-liter engine.
Overall, the Mack E7 460 is a reliable engine with its own set of quirks. It provides robust power for heavy hauling, good fuel efficiency, and, when properly maintained and operated, delivers dependable performance. While parts availability and service experiences can be inconsistent, the potential for a remaining warranty on rebuilt engines is a significant advantage.
