Project Grand Caddy has been around for well over two years now and has been a great daily driver and mild trail vehicle. Last June, the ZJ took a turn for the worse: It found itself a nice little hole in a river along the bank. Needless to say, the engine hydro-locked and bent the number eight rod.
The vehicle up until that point had been very dependable, even though the engine's odometer read 166,000. The motor was strong, offering plenty of power and torque with a slight push of the accelerator pedal. It didn't burn oil, nor did it smoke. The aforementioned unfortunate incident gave us the opportunity to play with one of our favorite contraptions, a well-rebuilt Mopar 5.2L Magnum small-block (318 ci).
The Mopar small-block has been around for a very long time. In 1964, it started life as a 273ci Mopar LA engine. Production of this engine lasted until 1992. The newer Magnum 5.2L small-block is basically an updated version of the LA engine and was produced from 1992 to 2001. A 5.9L version of the Magnum engine was produced from 1993 to 2003. The two share similar parts: In most cases, what fits on the LA engine will more than likely fit on the Magnum engine. Both Magnum engines found their way into the Jeep Grand Cherokee ZJ.
Unfortunately, we just don't have room in the magazine to give you a complete, step-by-step build of the engine. Instead, we will highlight the engine's high-quality Clevite components, performance options, important steps in the build process, and why the engine was built the way it was. If you're looking for complete, in-depth, small-block Mopar building, we highly recommend How to Rebuild Your Mopar Magnum V8 as reviewed in this month's Media Review department.
There are three companies that played a very important role in the build of this engine. Tim Jenkins at DOA Racing has been building top-shelf performance and race engines for many, many years. Tim directed all the machining and built the engine - we have the highest regard for Tim's engine-building abilities. Clevite Engine Parts is one of the world's largest manufacturers of engine parts. Clevite supplied some of the finest engine components available for this build. Don-A-Vee Chrysler and Jeep in Placentia, California, completed the installation of the new engine. Don-A-Vee has not only been selling Jeeps for the last 25 years, the company has been instrumental in Jeep enthusiast development. The dealership originally forged ahead to be one of the first in completing performance engine swaps on Jeep vehicles and has worked closely with Chrysler on Jeep development.
It would have been very easy to go all out and build our Grand's engine with the performance of a fighter jet (joke). The Mopar small-blocks are an excellent base to build a high-performance engine with 800-plus horsepower. Right off the bat, the engine is a little larger than most other small-blocks. The dimensions of the engine's crankcase offer more room for modifications. The block is a perfect match for stroker performance kits.
This vehicle is driven on a daily basis and used for extended travel, so gas mileage was a major factor in the build. The Grand Cherokee doesn't get that great of mileage as it is, so any performance modifications, such as a souped-up cam and higher compression, would have reduced fuel economy even more.
Tim found us a good, low-mileage engine core for a great price. The engine was thoroughly cleaned and then shipped off to the machine shop. Tim is one of the most knowledgeable engine builders we know. If you are serious about having your Jeep engine built properly, he is available for 4.0L straight-six and Mopar V-8 builds.We turned to Clevite Engine Parts for all internal components and received top-of-the-line Clevite engine bearings, Perfect Circle piston rings, and Victor Reinz gaskets. We spoke with Director of Brand Development Bill McKnight who educated us on a lot of the research and development behind Clevite performance parts.