How to Rebuild and Modify Jeep 4.0 Engines

The venerable Jeep 4.0-liter inline-6 engine has powered millions of Jeeps, including CJs, YJs. Wranglers, Cherokees, and Wagoneers. The 4.0 delivers adequate horsepower from the factory, but many off-road drivers want more horsepower and torque to conquer challenging terrain, which means these engines are often built and modified. The Jeep 4.0, or 242-ci, is affordable, abundant, exceptionally durable, and many consider it one of the best 4x4 off-road engines.

With this Workbench How-To Larry Shepard covers the rebuild of an entire engine in exceptional detail. He also delves into popular high-performance modifications and build-ups. Step-by-step photos and comprehensive captions detail each crucial step of the engine disassembly. He shows the inspection of all critical parts, including block, heads, rotating assembly, intake, and exhaust. Critical machining processes are explained, such as decking the block, line boring, and overboring the block. 

About the Author: Larry Shepard, a veteran Chrysler engineer, has worked for Mopar Performance and has extensive Jeep inline-6 knowledge. He has written five technical performance manuals for Chrysler. He is also a seasoned author, having written several Chrysler big-block high-performance and rebuild books.

TABLE OF CONTENTS:

Chapter 1:  The Jeep 4.0 Engine
Chapter 2:  Engine Removal
Chapter 3:  Disassembly
Chapter 4:  Inspection
Chapter 5:  Parts Selection
Chapter 6:  Building Stroker Engines
Chapter 7:  Machining and Prep
Chapter 8:  Preassembly and Final Cleaning
Chapter 9:  Short-Block Assembly
Chapter 10:  Long-Block Assembly and Initial Start-Up