Assembly

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M20B25 swap
Restore and fit an M20B25 in place of the locked M20B27, with raw aluminum, zinc plating, black accents and polished tubular headers.
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Plan
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Parts
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Gallery
Decisions & Unknowns
What I need to figure out:
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Use as the replacement for the locked M20B27.
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Finish the engine with raw aluminum, zinc plating and black accents.
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Reuse and polish the .
Tasks
What I need to do:
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Remove the failed M20B27 and prepare the M20B25 from a 1988 325i for restoration. Retain the 2.5-litre configuration.
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Clean and refinish the and .
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Restore the , and .
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Rebuild the with .
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Refinish the and replate the .
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Clean and rewrap the .
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Hand-sand and polish the .
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Reassemble the oil pan with , set valve lash and fit and .
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Reassemble the engine and manual drivetrain, then fit the M20B25 to the car.
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Fit and during engine finishing.
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Refinish the housing and flanges of the .
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Clean and refinish the casing and pulley of the . The compressor remained untested after refinishing.
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Fit custom firewall insulation: .
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Install the and before fitting the engine and transmission.
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Install the hardlines, finish bay preparation, fill the fluids and carry out the first start.