Jeep Engine Specs - 4.0 LITER, OHV, 12-VALVE SMPI POWER TECH I-6


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The Jeep 4.0 liter PowerTech Straight-Six engine provided exciting acceleration in Jeep Wranglers for years, with excellent torque. In the Cherokee it did well, in the Grand Cherokee it was a bit sluggish due to the weight of that vehicle.

When the 4.0 first came out, AMC was using two six cylinder engines, a troublesome 2.8 liter V6 from General Motors (with a problematic Ford carburetor) and AMC's own 258 CID straight-six, with 4.2 liters of displacement, that the 4.0 itself was based on. The 4.2 was used in the CJ7, and the YJ. While the 4.2 and 2.8 were both relatively strong for their day - the 4.0 beat just about all competing engines, including those of Japanese automakers. (The 4.2 produced about 112 hp in 1990, the 2.8 about 120 hp, and the 2.5 about 117 hp - torque was naturally higher in the 4.2).

When the 4.0 did burst onto the scene, it had a full 180 horsepower in the Wrangler and, in the Cherokee, it started out with 177 hp. The Cherokee's version made 190 hp starting in 1991. The YJ didn't get the 4.0 until the 1990s (it was still using the old 258 I6). When the YJ did get the 4.0, it only made 181HP due to the restrictive exhaust.

When the it was introduced, the 4.0 I6 made more power than the Ford 302 V8, Chevy 305, Chrysler 318, and AMC 360. It also was way more powerful than any 6 cylinder engines the Japanese were putting in their trucks... and had comparable or better fuel economy. It left the V6 engines from Ford, GM and Chrysler in the dust.
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Jeep Engine Specs - 4.0 LITER, OHV, 12-VALVE SMPI POWER TECH I-6 - Technical Specs

As found on a 2005 Jeep Wrangler:


Description</td><td>Specs</td></tr><tr><td>Availability</td><td>Std. - X, Sport and Rubicon</td></tr><tr><td>Type and Description</td><td>In-line, liquid-cooled</td></tr><tr><td>Displacement</td><td>242 cu. in. (3956 cu. cm)</td></tr><tr><td>Bore x Stroke</td><td>3.88 x 3.41 (98.4 x 86.7)</td></tr><tr><td>Valve System</td><td>OHV, 12 valves, flat followers, hydraulic lifters</td></tr><tr><td>Fuel Injection</td><td>Sequential, multi-port, electronic</td></tr><tr><td>Construction</td><td>Cast-iron block and head</td></tr><tr><td>Compression Ratio</td><td>8.8:1</td></tr><tr><td>Power (SAE net)</td><td>190 bhp (142 kW) @ 4600 rpm (47.5 bhp/L)</td></tr><tr><td>Torque (SAE net)</td><td>235 lb.-ft. (319 N•m) @ 3200 rpm</td></tr><tr><td>Max. Engine Sped</td><td>5300 rpm</td></tr><tr><td>Fuel Requirement</td><td>Unleaded regular, 87 octane (R+M)/2</td></tr><tr><td>Oil Capacity</td><td>6.0 qt. (5.7L)</td></tr><tr><td>Coolant Capacity</td><td>10.5 qt. (9.9L)</td></tr><tr><td>Emission Controls</td><td>Three-way catalytic converters, heated oxygen sensors, internal engine features(a)</td></tr><tr><td>Max. Gross Trailer Weight (lbs)</td><td>2,000 lbs. (907 kg)</td></tr><tr><td>Estimated EPA Fuel Economy mpg (City/Hwy)</td><td>16/20 - manual, 16/20 - automatic

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Jeep Engine Specs - 4.0 LITER, OHV, 12-VALVE SMPI POWER TECH I-6 - More Info

Description: in-line six, overhead valve (two per cylinder), flat-face followers, hydraulic lifters, cast iron block and head
Displacement: 3960 cc (242 cubic inches)
Bore and stroke 98.4 mm x 86.7 mm
Compression ratio 8.8:1
Redline: 5,300 rpm
Maximum power, 2003, Wrangler:
  • USA - 190 hp (142kW)@4,600 rpm; 235 lb-ft (319 Nm) @ 3,200 rpm
  • Europe - 130 kW (177 hp) @ 4600 rpm; 296 N·m @ 3500 rpm
    Fuel injection (final form): sequential multiple-port, electronic
In the Wrangler, 0-60 in 9.9 seconds (manual; 10.6 seconds, four-speed automatic); top speed 108 mph
European fuel economy (litres / 100KM)|Manual|Automatic
Combined cycle|13.2|15
Ex-urban cycle|9.0|10.7
Combined CO2|315 g/km|362 g/km
USA (EPA) fuel economy

Built in Kenosha, Wisconsin (5555 30th Avenue) - the plant also made the 2.7 and 3.5 liter engines at the same time. In 2003, it could make 405,673 4.0 engines per year (as well as 315,638 2.7s and 220,000 3.5s). The plant was built in 1917!
Does anyone know the dimensions of the full engine, accessories and all?

I'm planning a full jeep drivetrain swap into my '86 4Runner and need to know if it'll fit into my engine bay.


The Jeep 4.0L engine is a 4.0L (241.6 ci) 6-cylinder engine. It has a 3.8-inch bore and 3.41-inch stroke with 12 overhead jpeg2000alliance valves. This engine gets an 8.8-to-a compression ratio and produces 190 horsepower at 4600 RPMs and 235 lb-ft. Before you buy any vehicle, you need to know all of the specs and features.
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