SUBARU Engine Rebuild - EJ20 / EJ25 Teardown How To

Introduction

This tutorial provides a comprehensive guide to disassembling and rebuilding the Subaru EJ20/EJ25 engine. Whether you’re a seasoned mechanic or a DIY enthusiast, this step-by-step guide will help you understand the teardown process, ensuring you can confidently tackle your engine rebuild project.

Step 1: Gather Necessary Tools and Materials

Before starting the teardown, make sure you have all the required tools and materials:

• Basic Tools: Socket set, wrenches, and screwdrivers
• Specialized Tools:
  • Milwaukee Ratchet
  • Milwaukee Impact
  • Milwaukee Sawzall
  • Fluid Transfer Pump
  • Astro Rivnut Tool
• Safety Gear: Uvex Face Shield
• Lighting: Astro LED Work Light

Practical Tips

• Organize your tools for easy access.
• Wear safety gear to protect yourself during the process.

Step 2: Prepare the Work Area

Set up a clean and organized work area to facilitate the teardown. Consider the following:

• Work Surface: Use a sturdy table or bench.
• Lighting: Ensure adequate lighting to see small components clearly.
• Storage: Have containers or bags ready to keep screws and small parts organized.

Common Pitfalls to Avoid

• Working in a cluttered area can lead to lost parts.
• Not having enough light can make the teardown difficult.

Step 3: Remove Engine Components

Start the disassembly by removing key engine components:

1. Disconnect the Battery: Always disconnect the battery to prevent electrical shorts.
2. Drain Fluids: Drain the engine oil and coolant to avoid spills.
3. Remove Accessories:
   • Intake manifold
   • Exhaust manifold
   • Timing belt

Important Notes

• Keep track of where each component goes for easier reassembly.
• Use a camera or notes to document the disassembly process if needed.

Step 4: Take Apart the Engine Block

Once the accessories are removed, focus on the engine block:

1. Remove the Cylinder Heads: Unbolt the heads carefully, following the manufacturer's torque sequence.
2. Take Out the Pistons: Remove the connecting rods and pistons from the block.
3. Inspect the Crankshaft: Check for wear and damage.

Practical Tips

• Use a torque wrench to ensure proper reassembly later.
• Clean the block and heads thoroughly after disassembly.

Step 5: Clean and Inspect Components

After disassembly, clean all components and inspect them for wear:

• Use appropriate cleaning agents for metal parts.
• Check for cracks, warping, or excessive wear on the block, heads, and pistons.

Real-World Application

• Regular inspection can prevent costly repairs and ensure optimal engine performance.

Conclusion

You have now successfully disassembled the Subaru EJ20/EJ25 engine. This guide has covered the essential steps from preparation to inspection. The next steps include evaluating which parts need replacement and planning your reassembly. Always remember to follow safety protocols and maintain organization throughout the process for a smooth rebuild. Happy rebuilding!