BMW M54B25 2.5 Straight-Six Engine

About this engine

The naturally aspirated BMW six at its best: all-aluminium, double-VANOS, 192 hp and a genuinely linear 181 lb-ft, with the smoothness that made the E46 325i worth choosing over anything with four cylinders. No turbo, no direct injection, nothing that ages badly — which is exactly why people still swap these into everything. Our units were booked in marked "BMW 325i" and are photographed on the floor with the intake manifold, alternator and ancillaries fitted. The usual attention points on an M54 are the VANOS seals and the DISA flap; both are inexpensive to refresh and worth doing while the engine is out. Sold as a used import, exactly as it came out of the donor vehicle and as photographed. The engine code above is the one marked on this unit; we confirm it against the stamped engine number before dispatch. Compression and leak-down testing is available on request before you commit, and every unit carries a 3-month warranty against internal mechanical failure.

What you get

• Double-VANOS variable timing on intake and exhaust
• All-aluminium block and head — around 420 lb dressed
• 192 hp and 181 lb-ft, naturally aspirated and linear
• Complete with intake manifold, alternator and ancillaries

Known fitment

• BMW 325i E46 (2000-2006)
• BMW 525i E39 / E60
• BMW X3 2.5i E83
• BMW Z4 2.5i E85

This list is not exhaustive. If your chassis is not here, ask — most swaps come down to mounts and sump clearance.