Jeep Engines

I have decided that you all out there need to learn about all the engines that Jeep has used in the past. Sure, I may not have included EVERY engine every used. For example, I left out the GM 151 c.i. 4 cylinder and the GM 2.8L V6. I left those motors out because I hate them and they suck. I did include the 401, 360, 304, 258, Buick 225, AMC/Chryco 4.0, AMC/Chryco 4.7, and the AMC/Chryco 2.5L 4 cylinder. Click the pictures of the engines to see them full screen. Enjoy.

Explanation

The AMC 401 features a short stroke that turns the 401 into a torque monster. With insane torque at a low RPM, the 401 is a really good motor for propelling your late model Cherokee or CJ-7. Although the horsepower isn't really there, the engine is still great.

Engine Comparo!

AMC 360 V8                                            Dodge 360 V8

Explanation

The AMC 360 is much better that the Dodge version in everyway. While they may look similar, look closer and the AMC's stroke is shorter with a bigger bore, allowing for more torque at a lower RPM. The Dodge block has a longer stroke with a smaller bore allowing for the engine to create more horsepower, rather than torque. I prefer the AMC 360.

Explanation

The AMC 304 is a great little engine. While GM designed their small V8's, the 305 and 307, to be economy 8 bangers, the AMC 304 was designed to add some fire to the CJ series. With a nice short stroke and a decent bore, this engine has good compression and a lot of torque at a low peak RPM. The 304 is another great AMC engine.

Explanation

The AMC 258 is overall, a decent engine. It has very little horsepower, but it has a lot of torque at and EXTREMELY low peak RPM. This engine is set-up beautifully for towing and off road driving. The later models of the engine had a lot of carb trouble.

Explanation

The Buick 225 V6 is a very strong motor. It's knowing as an "odd firing" motor.. Meaning that it has an odd firing order that makes it run roughly. The 231, found in Grand National's was based on the 225 block later in life and to this day, the 231 block (3.8L) is still used. The new Monte Carlos and Impalas come clad with 231s. Back to the Jeep end though. Notice the MASSIVE fly wheel on the 225 pictured above. The 225 that was set-up for Jeeps used a bigger flywheel to help create more low end torque in order to give the Jeep that extra "umph". The 225 is all and all, a good motor.

The Current Jeep Motors

Explanation

The AMC/Chryco 4.0 litre inline six was originally designed by AMC as a size down from the 258 (4.2) inline six. The only difference is that the 242 (4.0) has a lot more power and a little less torque. It has a short stroke and a bigger bore creating a good combination of horsepower AND torque. Also, the Multi Port Injection helps for off camber, bouncy, and steep situations as it will not bog out like a carburetor. The engine is very strong and reliable and has only been improved upon since Chryco bought out AMC/Jeep. In 1991, Chryco added higher output (HO) intake and exhaust manifolds changing the overall torque and horsepower specs. Those specs are as follows.

Explanation

The Chryco 4.0 High Output has an additional 10 horsepower and an additional 15 ft lbs of torque over the AMC designed 4.0. Nonetheless, the bore and stroke remained the same as AMC hit a sweet spot for the perfect, reliable, off road oriented, engine.

Explanation

The Chryco 4.7 litre V8 was introduced 2 years ago in the 1999 Grand Cherokees. It is a fairly powerful motor with a good amount of torque. The engine features SOHC (single overhead cams) for that added horsepower (it's so choice).. New for 2001 is the 4.7 litre High Output for the Grand Cherokee "Overland" package. The stats for that are below.

Explanation

The Chryco 4.7L V8 HO is a big improvement over the original 4.7L V8. It has about 30 more horsepower than the regular 4.7L, about 30 ft lbs more torque as well. the 4.7L HO is truly a bad ass motor set-up for towing like a bastard!

Explanation

The Chryco 3.7L PowerTech V6 is the option motor in the all new Jeep Liberty. It is based on the 4.7L V8. The new 3.7L has decent horsepower, due to SOHC (single overhead cams) which aid in cranking out a little more power. However, these peaks are at a fairly high RPM. But the fact is, the Jeep Liberty outpulled the brand new supercharged Xterra.. So it can't be that bad!

Explanation

When the new downsized Jeep Cherokee came out in 1984, the current longest used engine came out with it. The 2.5L four cylinder. Yes, that 2.5L has been used longer than the 4.0. That same 2.5 has been fueled by all 3 different options there are... Carburetion, throttle body, and multi port injection. The new 2.5L comes with dual overhead cams that have totally changed the engine. All in all, I believe this engine will continue surviving because it has proved durable many times. My only complaint is that the horsepower peak RPM is through the roof. The only time your going to hit the peak is if you pin it and hold out the gears.

That's all the fun for now. I hope you all enjoyed this little engine teaching class.. And I hope that you can go out now and impress your Jeeping buddys! That's it for now, and I hope you continue checking back here at MJKH's Comanche for more!