Step 1: Complete Engine Strip-Down - Experts carefully disassemble your QR20DE/QR25DE engine, cataloging all components for inspection. Each part is cleaned and assessed for wear patterns specific to J31/J32 Presage models, identifying the root cause of failure.
Step 3: Critical Component Replacement - For QR20DE engines, head gaskets (11090-75Y00) are replaced as standard. QR25DE units receive new timing chains and tensioners (13510-75Y00) to prevent future failures. All gaskets and seals are renewed.
Step 5: Quality Testing & Verification - The rebuilt engine undergoes 4-hour dyno testing simulating real-world conditions for both J31 and J32 Presage models. Compression tests verify proper assembly before final quality certification.
Step 2: Precision Machining & Inspection - Cylinder heads are checked for warping and resurfaced if needed. QR20DE heads are particularly prone to warping due to head gasket failures. Block bores are measured for proper tolerances.
Step 4: Engine Reassembly with Updated Parts - Assembly uses genuine Nissan components with updated specifications. QR25DE engines receive improved timing chain guides to address known failure points in J32 models.
Step 6: Final Installation Preparation - The completed engine is fitted with new mounting hardware and tested for proper oil pressure, coolant flow, and electrical connections. All J31/J32 Presage-specific ECU requirements are verified.