1982 CJ7 Overhaul Part 4 - Installing the Crank & Pistons | Jeep Cherokee XJ 4.0 Engine Build

Building a Jeep 4.0 engine is all about precision…. Until a major mistake brings everything to a grinding halt. In Part 4 of our Jeep CJ7 overhaul series, we finally move from cleaning parts to engine assembly. We walk you through the technical process of installing the camshaft and crankshaft into our AMC 242 straight-six. It is important to note that this engine was swapped from a 2000 Jeep Cherokee XJ into our CJ7. We also take a deep dive into using Plastigage to measure main bearing clearances to ensure the engine live a long, healthy life. However, even the best-laid plans can go sideways. While installing one of the pistons, we hit a major setback - a damaged piston ring and the then the crushing realization that we have the wrong crankshaft for this specific 4.0 build! In this video you will see: Camshaft installation: Proper lube and seating techniques Crankshaft seating: How to set the crank and torque the main caps Plastigage tutorial: How to accurately check bearing clearances for a Jeep 4.0 Piston ring assembly: How to install and set the piston rings The Disaster: Bending a ring during piston installation The Wrong Crank: How to identify the difference between the 4.0 and 4.2 crankshaft If you have ever felt the frustration of a project moving backward, this episode is for you! Learn from our mistakes so you don’t make them on your own Jeep 4.0 engine rebuild! Subscribe to @theshop392 to see how we recover from this setback in Part 5 and finally get this CJ back on the trail! 00:00 - Introduction 01:10 - Camshaft Preparation and Installation 02:20 - Main bearing and Crankshaft installation 04:05 - Plastigage and Main bearing bolt torque sequence 09:08 - Crankshaft end play checks 10:24 - Piston ring installation 12:17 - Piston installation and rod cap plastigage checks 14:41 - Bending a piston ring while installing a piston 15:48 - Troubleshooting why the piston is above the block 19:28 - Teardown and wrapup