Jeep 4.0 Engine Rebuild: We Made a COSTLY Mistake! (Part 4) - Engine assembly attempt 1

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. We also take a deep dive into using Plastigage to measure main bearing clearances to engure 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