History and technical information of the Mack E7 engine
The Mack e7 engine is the backbone of the almighty Mack Bulldog fleet. The history of the engine is steeped in technology, tradition, and American common sense that one would expect from Mack. The e7 mack engine was first conceptualized in 1988 by engineers at Mack Corporation and introduced in 1989. The Mack E7 engine replaced the older Mack e6 model and was manufactured for more than 20 years. The same year, Mack also introduced the CH-series for heavy-duty on-highway applications. The engine is a 6-cylinder, rated for heavy duty and in use for both on-highway and off-highway industrial applications.
Mack engines are known for their torque output per pound-feet. They are workhorses in industrial applications, which means most Mack enthusiasts measure “power to the ground” above the high-horsepower capabilities of other diesels. Comparing a 400 hp CAT to a 400 hp Mack is like comparing cats to dogs. Competitors will compare engine power to the flywheel, while Mack’s competitive advantage comes into play with differentials and transmissions. This allows you to reduce power where you need it during pulling situations. Mack engines are not built for speed unlike Cummins, CAT or Detroit, but for long-term durability; perfect for service applications such as public bus fleets, fire trucks, garbage trucks and garbage vehicles. The optimum operating speed for the Mack e7 engine is 1400 to 1800 rpm, but it is not designed for high operating speeds. It’s not unlikely that a Mack Engine will go 1,500,000 miles hauling full loads and not need a major overhaul. Mack E7 engines are found in mining, oil and gas, agriculture, construction, pumps and compressors, and power generation.
Mack E7 engine technology
The typical horsepower rating of the Mack E7 is 250 to 400 hp. With the lowest rating of 250 hp, the Mack E7 engine will produce 975 pound-feet of torque. Consequently, the highest horsepower rating a Mack e7 engine will produce was 454 horsepower with an impressive 1,660 pound-feet of torque. The vast majority of mack e7 engines still on the road are later models that are all water cooled. The original design through 1990 featured a turbocharged air-mounted cooling system. After 1990, Mack engineers developed their patented Econovance variable injection timing system that greatly increased fuel efficiency and reduced emissions. Many speculate that Mack redesigned the engine to meet Environmental Protection Agency emission standards. Since 1990 further redesigns have been implemented to comply with EPA regulations. The Econovance system was used exclusively on the E7 engine but was not adopted by other production lines at Mack. In addition to the Ecconovance technology, Mack also introduced another modification to its E7 line that improved the efficiency of the air/fuel ratio through a high injection pressure combustion system known as “swirl technology” that greatly increased the air flow. The higher pressure injection system improved fuel economy and combustion productivity while optimizing proper oil viscosity and reducing engine emissions. Due to the increased airflow, a by-product is less pressure on the injectors. Customers are happy to discover that injector failure is quite uncommon on Mack E7 models.
Introduction to the Mack E-Tech engine
The Mack E7 engine ended up being one of the most popular industrial diesel engines of all time. Both large-scale and small-scale operations flocked to the Mack E7 engine due to its reliability and fuel efficiency. Through 1999, Mack ended up producing 16 different varieties of the E7. 1999 ended up becoming a landmark year for Mack when he once again hit a home run with his Mack E-Tech series. Mack E-Tech engines are still in production and are still known for their excellent power-to-weight ratio. The Mack E-Tech engines are multi-system cooled 6-cylinders and are rated at 360 to 500 hp. The fuel injection system uses an update to the E7’s Econovance technology called the Mack V-Mac III electronic fuel control system that uses electronic unit pumps. The E Tech engine also uses high-swirl combustion to increase fuel efficiency and emissions output. Like the E7, the E-Tech features a dual-flow paint oil lubrication system with a 34-quart capacity. The E-Tech has upgraded highly rated steel ridge articulated pistons and wet and dry liners for long lasting strength.
Mack E7 Engine Rebuild Process
Typical machine shop crews should be quite knowledgeable about rebuilding and rebuilding Mack E7 and E-Tech engines as it was a popular engine. Most auto shops specialize in Mack Longblocks, which are ¾ of an engine vs. a complete rebuild. Make sure the mack e7 engine is remanufactured by the machine shop to your specific serial number and is built to the original engine manufacturer’s specifications. A typical remanufactured mack e7 consists of:
• Remanufactured cylinder block
• Remanufactured Cylinder Head
• Remanufactured connecting rods
• Remanufactured crankshaft (standard/standard or oversized)
• Remanufactured oil pump
• Remanufactured camshaft
• Remanufactured rocker arm assemblies
• New water pump
• New cylinder liners
• New pistons
• New piston rings
• New gaskets
• New main and connecting rod bearings
• New thrust washers
• New camshaft bushings
• New tappets and cam followers
• OEM or aftermarket internal parts
Most machine shops can typically rebuild an existing core or rebuild and return an engine in about 16 days.