The Mack e7 engine is the backbone of the mighty Mack Bulldog fleet. The history of the engine is steeped in technology, tradition and American good sense that one would expect from Mack. The mack e7 engine was first conceptualized in 1988 by Mack Corporation engineers and introduced in 1989. The Mack E7 engine replaced the older Mack e6 model and was in production for more than 20 years. The same year, Mack also introduced the CH Series for heavy duty highway applications. The engine is 6-cylinder, heavy-duty rated and in use for both on-highway and off-highway industrial applications.
Mack engines are known for their torque power per foot pound. They’re workhorses in industrial applications, which means that most Mack enthusiasts measure “power to the ground” over the high-horsepower capabilities of other diesel engines. Comparing a 400 hp CAT to a 400 hp Mack is like comparing cats to dogs. Competitors will compare the power of the engine at the flywheel as Mack’s competitive advantage comes into play with the differentials and transmissions. This allows you to lower 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, dump trucks and waste vehicles. The optimal operating speed for the Mack e7 engine is 1400-1800 rpm, but it is not designed for high operating speeds. It’s not unlikely that a Mack engine will go 1,500,000 miles carrying 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
Typical power rating for the mack e7 is 250 to 400 hp. At the lowest rating of 250 hp, the mack e7 engine will produce 975 pound-feet of torque. Consequently, the highest power rating a Mack e7 engine will produce was 454 hp with an impressive 1,660 pound-feet of torque. The vast majority of mack e7 engines that are still on the road are later models that are all water-cooled. The original design until 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 more 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 Ecconovance technology, Mack also introduced another modification to its E7 line that improved the efficiency of the air / fuel mixture ratio through a high-pressure injection combustion system known as “swirl technology” that was 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 air flow, a by-product is lower pressure on the injectors. Customers are happy to find that injector failure is quite rare with 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. Until 1999, Mack ended up producing 16 different varieties of the E7. 1999 ended up becoming a landmark year for Mack when, once again, he homered with his Mack E-Tech series. Mack E-Tech engines are still in production and are still known for their excellent horsepower-to-weight ratio. Mack E-Tech engines have 6-cylinder multi-system cooling and range from 360 to 500 hp. The fuel injection system uses an upgrade 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 turbulence combustion to increase fuel efficiency and emission production. Like the E7, the E-Tech features dual-flow paint in an oil lubrication system with a 34-quart capacity. The E-Tech has upgraded articulated pistons with highly rated steel crest and both wet and dry coatings for long-lasting strength.
Mack E7 engine rebuild process
Typical machine shop crews should be quite knowledgeable about rebuilding and remanufacturing Mack E7 and E-Tech engines as it was a popular engine. Most auto shops specialize in Mack Longblocks, which are 3/4 of an engine versus a complete rebuild. Make sure the machine shop re-builds the mack e7 engine with its 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 oversize)
• Remanufactured oil pump
• Remanufactured camshaft
• Remanufactured rocker arm assemblies
• New water pump
• New cylinder liners
• New pistons
• New piston rings
• New boards
• New main and connecting rod bearings
• New thrust washers
• New camshaft bushings
• New tappets and cam followers
• Internal OEM or aftermarket parts
Most auto shops can typically remanufacture an existing core or rebuild and return an engine in approximately 16 days.