Subaru Boxer Crankshaft Assembly Replacement

Precision-balanced crankshaft for Subaru flat-four engines. It turns piston motion into smooth rotation, reducing vibration and keeping torque steady. Hardened journals, oil grooves, and matched counterweights protect bearings and maintain oil film at high RPM. Built for long life and clean lubrication, it’s the core of a healthy bottom end.

Why you need it ✅

Replace when the old unit shows scoring, cracks, oval journals, or excess end‑play. A new assembly restores oil pressure, quiet idle, and timing accuracy, protecting rods, pistons, and block. Ideal for rebuilds, performance refresh, or repairing bearing failures.

How it works ⚙️

Main journals support in the block; rod journals drive the rods. Counterweights balance boxer firing pulses. Internal oil passages feed each journal; thrust faces control end‑play. The front snout locates the damper and timing drive for stable rotation across the rev range.

What happens if it’s damaged ❗

If worn or damaged you’ll hear deep knocks, see metal in oil, feel vibration, and may get low pressure or misfires. Driving on it can spin bearings, starve the pump, break a rod, or seize the engine—often ruining block and heads.

Install tips

Check line‑bore, measure clearances, and install new bearings. Torque caps in sequence and pre‑lube journals. Fit new front/rear seals, inspect damper and oil pump gears, and finish with clean oil and proper break‑in.

Compatibility

• Legacy
• Forester
• Wrx/Levorg
• Brz
• Wrx