| How-To

Trucks, Trailers & Towing - Hauling With The Hemi

Dodge Puts Legendary Power in Today's Trucks

Performance gains through a hemispherical combustion chamber were proven on a racetrack decades ago. The world of NASCAR racing was put on its ear when a Hemi-powered car blistered Daytona in 1964, only to see the engine outlawed later. The reason for its banishment was the fact that it was a purpose-built race engine and not available in street machines. After a year out, Chrysler bit the bullet, produced a street version, and the racing efforts picked up right where they left off.

Fast-forward several decades. The street Hemi fell victim to environment concerns and rising gasoline prices. It became a museum piece with a sort of reverence that is held only for the elite. If you saw it on the street, it was beneath the hood of a vintage muscle car, proudly restored by a dedicated owner.

As the automotive scene evolved, the power and performance aspects for light-duty and heavy-duty truck lines began to get more attention. With the knowledge acquired from the first two generations of the Hemi, Chrysler set about for a resurgence of a proven winner.

The dawn of the 21st century brought about the 50th anniversary of the legendary Hemi. Soon, Chrysler put the Hemi back on the street, this time encapsulated in Dodge trucks.

Truck buyers can now have the power and performance of the Hemi engine, completely legal within the boundary of modern restrictions. The engine is standard on the 2500 (31/44-ton) and 3500 (one-ton) series. Recently, Dodge put the engine into the option group for the 1500 Ram with the option running about $800.

The new Hemi is officially called the 5.7-liter Hemi Magnum V-8. It replaced the 5.9-liter engine previously found in the trucks. The 5.7-liter Hemi is capable of producing 100 more horsepower and 40 more ft./lbs. of torque than the 5.9-liter model. In addition, the hemi engine is about 60 pounds lighter, and fuel efficiency is about 10 percent better. There is also an improvement in the emissions range for the 5.7-liter Hemi as compared to the 5.9-liter equipped trucks.

The Hemi engine borrows heavily from the theory of its predecessor, but the modern technology replaces plenty of the original workings of the 426 model. Two features that carried over are critical to the engine's workings. The hemispherical combustion chambers that gave the hemi its moniker are an integral element. These chambers feature the large valves that put the spark plugs close to the center of the combustion chamber. Another original idea in the new model is the cross-flow valve arrangement that puts the valves perpendicular to the crankshaft centerline.

The Hemi is an internally balanced pushrod 90-degree V-8 engine (OHV) with a cast-iron block. The cast-iron block is a deep skirt model with cross-bolted main caps. Cylinder bore spacing is the same as the 5.9-liter model. The engine has two valves per cylinder (aluminum alloy heads) and also features dual spark plugs and a coil-over-plug ignition. There is an integrated air fuel module (IAFM) that utilizes the function of 26 components in induction and fuel system. The designers focused on engine sealing, using a combination of premium elastomeric materials and state-of-the-art application practices. The simple and efficient design of the engine was directed at easing servicing and repair.

Optimal air flow is achieved with the spark plugs, direct ignition, and electronic throttle control (ETC), Chrysler's first "drive by wire" system. The ETC moves the throttle in response to the accelerator position. It's based on engine torque control and compensates for changes in the engine demand, brought about by factors such as the alternator, air conditioning, etc.

The engine serves as the backbone for providing higher-working capabilities of the truck. The 354ci engine rates at 345 hp and carries 375 ft./lb. of torque (torque and horsepower rated on 2500 series truck. Peak horsepower reached at 5400 rpm while peak torque was achieved at 4200 rpm). This power provides plenty of towing capability.

Company officials plan to produce 440,000 Hemi engines each year, a far cry from the limited production of the late '60s and early '70s. The latest engine went through 11 million miles of testing in extreme conditions (including high heat followed by rapid extreme cooling) before being released to the public. Chrysler is offering a 7 year/70,000 mile warranty on the 5.7-liter Hemi Magnum engine.

"That thing got a Hemi in it?" is a question that wasn't heard a few years ago, but it has become part of a Chrysler marketing campaign of humorous television commercials. There's nothing funny about the commitment to provide a quality production engine to benefit today's truck consumer. The next generation Hemi isn't resting on its reputation. It's a classic example of how to incorporate proven ideas into the demands of today's truck market with the right mix of new and old. It may not have the dual Carter carburetors like its predecessor, but you can't argue the numbers. Based on its reputation, it's no surprise that the Hemi is back in a big way.

Displacement: 354 cubic inchesBore x stroke: 3.92 x 3.58 (inches)Valve system: Pushrod-operated overhead valves, 16 valves, hydraulic lifters with roller followersCompression ratio: 9.6:1Power (SAE net): 345 bhp @ 5400 rpm (2500 series)Torque (SAE net): 375 ft./lb. @ 4200rpm (2500 series)Maximum engine speed: 5,800 rpmFuel requirement: Unleaded mid-grade (89 octane) recommended, 87 octane acceptableOil capacity: 7 qt. Coolant capacity: 18.7 qt