The Mack e7 engine is the backbone of the almighty Mack Bulldog fleet. The history of the engine is steeped in technology, tradition and good old American gumption one would expect from Mack. The e7 mack engine was first conceptualized in 1988 by the Mack Corporation engineers and introduced in 1989. The Mack E7 Engine replaced the longstanding Mack e6 model and was produced for over 20 years. The same year Mack also introduced the CH Series for on-highway heavy duty applications. The engine is 6 cylinder, heavy duty rated and in use both for on-highway and off highway industrial applications.
Mack engines are known for their per foot pound of torque output. They are workhorses in industrial applications meaning most Mack enthusiasts measure “power to the ground” over 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 engine strength at the flywheel whereas Mack’s competitive advantage comes into play with the differentials and transmissions. This allows power down low 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 like Public Bus Fleets, Fire Engines, Dump Trucks and Refuse Vehicles. The Mack e7 engine’s optimal running rate is at 1400-1800 rpms but isn’t designed for high running rates. It is not unlikely to have a Mack Engine put 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
Typical horsepower rating for the mack e7 is between 250-400 hp. At the lowest rating of 250 hp the mack e7 engine will put out 975 foot pounds of torque. Consequently, at the highest hp rating a Mack e7 engine will put out was 454 hp at an impressive 1,660 foot pounds of torque. The vast majority of mack e7 engines still on the road are later models which are all water cooled. The original design up until 1990, featured a turbocharged air mounted cooling system. After 1990 Mack engineers developed their patented Econovance variable injection timing system which increased fuel efficiency greatly and cut emissions. Many speculate Mack redesigned the engine to meet the Environmental Protection Agency’s emissions standards. Since 1990 more redesigns have been implemented to meet EPA regulations. The Econovance system was used exclusively on the E7 engine but not adopted by other production lines at Mack. In addition to the Ecconovance technology Mack also introduced another modification to its E7 line which improved the efficiency of the air/fuel mixing ratio through a high injection pressure combustion system known as “swirl technology” which increased airflow greatly. The higher pressure injection system improved fuel economy and combustion productivity all while optimizing proper oil viscosity and reducing engine emissions. Due to the increased air flow a byproduct is less pressure on the injectors. Customers are happy to find that injector failure is quite uncommon with Mack E7 models.
Mack E-Tech Engine Introduction
The Mack E7 Engine ended up being one the most popular industrial diesel engines of all time. Both large scale and small scale operations flocked to the Mack E7 Engine because of its reliability and fuel efficiency. Up until 1999 Mack ended up producing 16 different varieties of the E7. 1999 ended up becoming a landmark year for Mack when once again it hit a home run with its Mack E-Tech series. Mack E-Tech engines are still being produced and are still known for their outstanding horsepower to weight ratio. Mack E-Tech engines are 6 cylinder multi-system cooled and range from 360 to 500 hp. The fuel injection system uses an upgrade to the Econovance technology of the E7 called the Mack V-Mac III electronic fuel control system which utilized electronic unit pumps. The E Tech engine also uses high swirl combustion for increased fuel efficiency and emissions production. Like the E7 the E-Tech features dual flow paint on oil lubrication system with a 34 quart capacity. The E-Tech has upgraded high rated steel crest articulated pistons and both wet and dry liners for long standing resilience.
Mack E7 Engine Rebuild Process
Typical machine shop crews should be fairly knowledgeable at rebuilding and remanufacturing Mack E7 and E-Tech engines as it was a popular engine. Most machine shops specialize in Mack Longblocks which are ¾ of an engine vs, a full rebuild. Make sure the machine shop remanufactures the mack e7 engine to your specific serial number and is built to original engine manufacturer specifications. A typical remanufactured mack e7consists of:
• Remanufactured Cylinder Block
• Remanufactured Cylinder Head
• Remanufactured Connecting Rods
• Remanufactured Crankshaft (std/std or oversized)
• Remanufactured Oil Pump
• Remanufactured Camshaft
• Remanufactured Rocker Arms Assemblies
• New Water Pump
• New Cylinder Liners
• New Pistons
• New Piston Rings
• New Gaskets
• New Main and Rod Bearings
• New Thrust Washers
• New Camshaft Bushings
• New Tappets and Cam Followers
• OEM or Aftermarket Internal Parts
Most machine shops can typically can remanufacture an existing core or rebuild and return an engine in approximately 16 days.