The initial design development for the PowerTech V6 and V8 engine family was done by American Motors Corporation (AMC) and debuted in 1998 with credit to Chrysler. This was the first new V8 engine for Chrysler since the 1960s. The companion V6 was basically the V8 with two fewer cylinders, another concept that originated at AMC before the company joined Chrysler. These new engines had nothing in common with the Chrysler LA engine V8s, nor the Jeep 4.0 L "PowerTech" I6 engine.

A 4.7 L V8 came first, available in the Jeep Grand Cherokee, and a 3.7 L V6 version debuted in 2002 for the Jeep Liberty. The PowerTech V6 and V8 were direct replacements for Chrysler's Magnum series in the early 2000s, and were also used in the Dodge Ram and started in the 2000 Dodge Durango. They were not used in any cars, but were reserved for truck and SUV use. They are also known as Next Generation Magnum in Dodge applications.

The PowerTech V6 and V8 engines were produced at the Mack Avenue Engine Complex in Detroit, Michigan. E85 compatible versions of some PowerTech engines were developed and used in numerous Chrysler vehicles. On April 9, 2013, the last 4.7 L engine was built; ending 15 years of production with over 3 million units built.

4.7

The 4.7-liter version was the first of this family, appearing in the 1999 Jeep Grand Cherokee. The displacement is with a bore and a stroke of . It has a cast iron block and aluminum heads with two valves per cylinder. It uses chain-driven Single overhead camshafts, one in each head. It originally produced and of torque. The 4.7 L V8 is available with four speed and five speed automatic transmissions and a 5 speed manual transmission.

The PowerTech was on the Ward's 10 Best Engines list for 1999.

1999–2009 Jeep Grand Cherokee 2000–2007 Dodge Dakota 2000–2009 Dodge Durango 2002–2010 Dodge Ram 1500 2006–2009 Jeep Commander 2007–2009 Chrysler Aspen 2006–2007 Mitsubishi Raider

4.7 HO

A "High-Output" version of the 4.7 L PowerTech engine, producing and of torque, was introduced in 2002, first appearing in the Jeep Grand Cherokee Limited as an option and in the Jeep Grand Cherokee Overland as standard equipment.

This engine was discontinued after the 2008 model year, though the non high output 4.7L V8 engine continued to be available in all vehicles.

Applications: 2002–2004 Jeep Grand Cherokee 2007–2008 Jeep Grand Cherokee 2007–2008 Dodge Dakota 2007–2008 Dodge Ram 1500

2008 Revisions

The 2008 Dodge Dakota and Ram pickup trucks, Dodge Durango and Chrysler Aspen SUV's, Jeep Grand Cherokee, and Jeep Commander came with a Corsair version of the FFV 4.7 L engine, with dual spark plugs per cylinder, a new slant / squish combustion system design, and 9.8:1 compression, raising power to and of torque. The 2008 4.7 also features other upgrades including a more aggressive camshaft profile, a throttle body, and an improved intake manifold with shorter runners.

3.7 EKG

The EKG is a 3.7 L V6 version built in Detroit, Michigan. It displaces . The bore and stroke measure . It is a 90° V engine like the V8, with SOHC 2-valve heads. It utilizes a counter-rotating balance shaft mounted between the cylinder banks to deal with vibration problems of the 90-degree V6 design, as well as use a 30-degree split pin crankshaft to fire the cylinders every 120 degrees. Output is at 5200 rpm with of torque at 4000 rpm. It has a cast iron engine block and aluminum SOHC cylinder heads. It uses Sequential fuel injection, has roller followers, and features fracture-split forged powder metal connecting rods and an assembled reinforced plastic intake manifold.

The Chrysler 3.7 PowerTech engine used in the 2007–2012 Jeep Liberty KK used a wasted spark ignition system that uses one ignition coil to fire two cylinders.

3.7 Engine SpecificationsDescriptionSpecificationFiring Order1-6-5-4-3-2Lead Cylinder#1 Left BankCompression Ratio9.6:1Oil Pressure at Idle4 psi (25 kPa)Oil Pressure @ 3000 RPM25-110 psi (170-758 kPa)Max Variation Between Cylinders25%Compression170-225 PSI (1172-1551 kPa)Cylinder Bore Diameter3.6619 in. (93.013 mm)Cylinder Out of Round (max)0.003 in. (0.051 mm)Cylinder Taper (max)0.002 in. (0.051 mm)PistonsPiston Diameter3.6605 in. (92.975 mm)Piston Weight12.87 oz. (365.0 grams)Ring Groove DiameterNo. 1: 3.282-3.273 in. (85.37-83.13 mm) No. 2: 3.261-3.310 in. (82.833-83.033 mm)

No. 3: 3.302-3.310 in. (83.88-84.08 mm)Piston Pin Diameter0.9455-0.9456 in. (24.017-24.020 mm)Piston Pin Clearance0.0002-0.0005 in. (0.006-0.015 mm)Piston Ring GapTop Compression Ring0.0076-0.0142 in. (0.20-0.36 mm)Second Compression Ring0.0146-0.0249 in. (0.37-0.63 mm)Oil Control Ring (Steel Rails)0.0099-0.30 in. (0.25-0.76 mm)Piston Ring Side ClearanceTop Compression Ring0.0020-0.0037 in. (0.051-0.094 mm)Second Compression Ring0.0016-0.0031 in. (0.040-0.080 mm)Oil Control Ring0.0007-0.0091 in. (0.019-0.229 mm)Piston Ring WidthTop Compression Ring0.057-0.058 in. (1.472-1.490 mm)Second Compression Ring0.057-0.058 in. (1.472-1.490 mm)Oil Control Ring0.017-0.018 in. (0.445-0.470 mm)Connecting RodsBearing Clearance0.0002-0.0017 in. (0.006-0.044 mm)Side Clearance0.004-0.0138 in. (0.10-0.35 mm)Piston Pin Clearance0.0006-0.0011 in. (0.015-0.028 mm)Bearing Bore Out of Round (max)0.0002 in. (0.004mm)Total Weight (No Bearing)21.588 Ounces (612 Grams)CrankshaftMain Bearing Journal Diameter2.4996-2.5005 in. (63.488-63.512 mm)Main Bearing Clearance0.00008-0.0018 in. (0.002-0.048 mm)Main Bearing Out of Round (max)0.0002 in. (0.282 mm)Main Bearing Taper (max)0.0004 in. (0.006 mm)Connecting Rod Journal Diameter2.2798-2.2792 in. (57.908-57.892 mm)Connecting Rod Bearing Clearance0.0002-0.0011 in. (0.006-0.044 mm)Connecting Rod Bearing Out of Round (max)0.0002 in. (0.005 mm)Connecting Rod Bearing Taper (max)0.0002 in. (0.006 mm)End Play0.0021-0.0112 in. (0.052-0.282 mm)CamshaftBore Diameter1.0245-1.0252 in. (26.02-28.04 mm)Bearing Journal Diameter1.0227-1.0235 in. (25.975-25.995 mm)Bearing Clearance0.001-0.0026 in. (0.025-0.065 mm)End Play0.003-0.0079 in. (0.075-0.200 mm)Valve TimingValve Overlap25.7°IntakeOpens (Before Top Dead Center)5.6°Closes (After Top Dead Center)240.1°Duration245.7°ExhaustOpens (Before Top Dead Center)241.5°Closes (After Top Dead Center)20.1°Duration261.6°ValvesFace Angle45°-45.5°Head DiameterIntake 1.9103-1.9205 in. (48.52-48.78 mm)Exhaust1.4516-1.4618 in. (36.87-37.13 mm)Length (Overall)Intake4.4666-4.4965 in. (113.45-114.21 mm)Exhaust4.5244-4.5543 in. (114.92-115.68 mm)Stem DiameterIntake0.2729-0.2739 in. (6.931-6.957 mm)Exhaust0.2717-0.2728 in. (6.902-6.928 mm)Stem-to-Guide ClearanceIntake0.0008-0.0028 in. (0.018-0.069 mm)Exhaust0.0019-0.0039 in. (0.047-0.098 mm)Valve Lift (Zero Lash)Intake0.472 in. (12.00 mm)Exhaust0.472 in. (12.00 mm)Valve SpringsFree LengthIntake1.896 in. (48.18 mm)Exhaust w/ Damper1.973 in. (49.2 mm)Spring Force (Closed Valve)Intake74.53-82.72 lbs. @ 1.5795 in (332.0-358.0 N @ 40.12mm)Exhaust w/o Damper80.031-88.57 lbs. @ 1.54 in. (356-394 N @ 39.12 mm)Spring Force (Open Valve)Intake213.2-233.8 lbs. @ 1.107 in. (948.0-1038.0 N @ 28.12 mm)Exhaust w/o Damper196.5-214.9 lbs. @ 1.057 in. (874-856 @ 27.12 mm)Number of CoilsIntake7.30Exhaust7.15Wire DiameterIntake0.1878 x 0.1496 in. (4.77 x 3.80 mm)Exhaust0.1843 x 0.1464 in (4.66 x 3.72 mm)Installed Height (Spring Seat to Bottom of Retainer)Intake 1.579 in. (40.12 mm)Exhaust w/ Damper1.579 in. (40.12 mm)Cylinder HeadGasket Thickness0.0276 in. (0.7mm)Valve Seat Angle44.5°-45.0°Valve Seat Runout (max)0.002 in. (0.051 mm)Valve Seat Width+Intake Exhaust0.0698-0.0928 in. (1.75-2.36 mm)0.0673-0.091 in. (1.71-2.32 mm)Guide Bore Diameter0.2747-0.2756 in (6.975-7.00 mm)Cylinder Head Warpage (Flatness)0.002 in. (0.0508 mm)

Applications 2002–2010 Dodge Ram 1500 2002 Dodge M80 2004–2011 Dodge Dakota 2004–2009 Dodge Durango 2007–2011 Dodge Nitro 2002–2012 Jeep Liberty 2005–2010 Jeep Grand Cherokee 2006–2010 Jeep Commander 2006–2010 Mitsubishi Raider 2011–2012 Ram 1500

References

External links

Allpar's page on the 3.7L Allpar's page on the latest 4.7L 3.7L V6 PowerTech Engine: Specs, Problems, Reliability