The Chrysler 4.7L V8 PowerTech is an eight-cylinder gasoline engine that first appeared in the Jeep Grand Cherokee in 1999 and was subsequently used in Dodge vehicles (from 2000 to 2002).
The 4.7L V8 was the first of the PowerTech series, designed to replace AMC's 4.0L inline-six engine and Chrysler's 316 V8s in the LA family. Despite the fact that it had nothing to do with the prior 5.2L Magnum, the new 4.7-liter V8 engine in Dodge automobiles was nicknamed the 4.7L Magnum for a time.
The PowerTech series was extended in 2002 to include a 3.7-liter V6 engine that looked quite identical to the V8 version.
The 4.7L PowerTech has a cast-iron cylinder block with a bore spacing of 4.09 inches (104 mm), a deck height of 9.09 inches (231 mm), and a 90-degree angle between cylinder banks, suitable for using one crankpin journal for two connecting rods.
The engine block was completely redesigned from the ground up. Instead of five independent main-bearing covers, the first engine used a nodular cast-iron crankshaft that was linked to the block with a single bedplate. The block is stiffened by the compacted graphite iron bedplate, which also reduces noise and vibration.
This engine has powder-forged metal connecting rods with fracture-split fractures (length: 6.12 inches/155.5 mm) and cast aluminium pistons with moly coated skirts. The crankcase is sealed from the bottom by a stamped steel oil pan. Although the 3.7L V6 engine has a balancing shaft, the 4.7L engine does not.
The cylinder heads of the engine are composed of cast aluminium alloy. Each head is separated from the engine block by a three-layer laminated stainless steel gasket. The head bolts have a diameter of 11 mm. Each cylinder head has just two valves and a single top-mounted, chain-driven hollow camshaft (SOHV design).
The rocker arms are turned 180 degrees and the intake and exhaust valves are pushed apart. The design of the combustion chamber and the location of the spark plugs were improved because to this arrangement (almost hemispherical chambers). The diameter of the intake valves is 1.89 inches (48 mm), while the diameter of the exhaust valves is 1.46 inches (37 mm).
In the valvetrain, hydraulic lash adjusters are mounted. The intake valve lift is 0.443 inches, while the exhaust valve lift is 0.429 inches. The intake has a length of 244 degrees, while the exhaust has a duration of 254 degrees. Above each cylinder head is a cast magnesium valve cover.
The engine is equipped with an electronic fuel injection system (sequential multi-port injection). The fuel injectors are connected to the intake port on the head. The new tuned-length runner intake manifold is made of polymer material.
The engine's speed is controlled by an electronic throttle body (fly-by-wire). The throttle valve is 2.56 inches in diameter (65 mm). A hybrid cooling fan system and a modern coil-on-plug ignition system are also included in the 4.7 V8 engine (in-line electric and engine-driven fans).
The Jeep Grand Cherokee Limited received a "High-Output" variant of the 4.7L PowerTech engine in 2002, which was made standard on Overland models. The 4.7L V8 HO comes standard with a 9.7:1 compression ratio, high-compression domed pistons, two knock sensors, altered camshafts, and a reworked intake.
This engine has 30 more horsepower and 35 more pound-feet of torque than a normal engine. In 2005 and after, the 4.7L H.O. version of the Jeep Grand Cherokee was replaced with a 5.7L V8 Hemi, however it was remained available for certain models until 2008.
In 2005, the basic version received knock sensors and other minor tweaks. However, since 2008, the 4.7L PowerTech has undergone significant changes. Starting with the 2008 model year, the 4.7L V8 PowerTech engine has new cylinder heads with two spark plugs per cylinder (by the way, these two spark plugs are not identical).
On the bottom, new lightweight pistons and forged steel connecting rods (36MnVS4 material) were added. The compression ratio was increased from 9.0:1 to 9.8:1. The ports on the heads have been changed to increase flow. In the valvetrain, a new valve lash adjustment system was added. The new 4.7L engine has a more aggressive camshaft profile, a better intake manifold with shorter runners, and a 2.91-inch throttle body (74 mm).
The PowerTech V8 4.7L engine was used in the Dodge Ram 1500 for the longest time, lasting until the 2013 model year. This 4.7-liter V8 engine was replaced by the 3.6 V6 Pentastar and contemporary Hemi V8 engines, which were more technologically sophisticated.
Manufacturer: Chrysler, Mack Avenue engine plant, Detroit, Michigan
Production years: 1999-2013
Cylinder block material: Cast iron
Cylinder head material: Aluminium
Fuel type: Gasoline
Fuel system: Sequential multi-port fuel injection
Number of cylinders: 8
Valves per cylinder: 2
Valvetrain layout: SOHC
Bore: 93.0 mm (3.66 in)
Stroke: 86.5 mm (3.40 in)
Displacement: 4,698 cc (286.7 cu in)
Type: Four-stroke, naturally aspirated
Compression Ratio: 9.0:1, 9.7:1 - High-Output version, 9.8:1 - 2008+
Power: 235-310 hp (175-231 kW) at 4,600-5,650 rpm
Torque: 295-334 ft-lb (400-453 Nm) at 3,600-4,000 rpm
Firing order: 1-8-4-3-6-5-7-2
Engine oil weight: SAE 5W-30 (SAE 5W-20 from 2008)
Engine oil capacity: 5.7 litres (6.0 qt) - with oil filter
Oil change interval: 6,000 miles (10,000 km) or 6 months
Applications: Jeep Grand Cherokee, Jeep Commander, Dodge Ram 1500, Dodge Dakota, Dodge Durango, Chrysler Aspen, Mitsubishi Raider
Reliability & Issues
The powerplant's owners had mixed opinions about it. Modern technology supporters believe that the new engine was too conservative, and that shifting the camshafts to the heads provided no significant gains. The previous Magnum V8 was, on the other hand, more powerful and durable, and the Hemi V8s are a superior alternative among modern engines.
The 4.7L V8 PowerTech, on the other hand, is a reliable engine with a straightforward design. It has a robust cast-iron block and bedplate, a limited number of potentially failing electrical gadgets, and reliable timing chains. Early models had problems with failed hydraulic lash adjusters, which might force rocker arms to kick out of their functional positions.
The engine might survive for roughly 150,000 miles with only basic maintenance (240,000 kilometres). Keep in mind, though, that the PowerTech engine family does not tolerate indifference. The engine requires thin oils and a short time between oil changes; otherwise, the engine's interior gets quite dirty, leading to more serious problems.