The BMW N73 is a naturally aspirated V12 petrol engine which replaced the BMW M73 and was produced from 2003–2016. It was used in the BMW 7 Series (E65) and Rolls-Royce Phantom VII. The N73 was the world's first production V12 engine to use gasoline direct injection. Compared with its M73 predecessor, the N73 has dual overhead camshafts, double-VANOS (variable valve timing) and valvetronic (variable valve lift).

Design

The variable valve timing (VANOS) is a continuously variable design and is present on both the intake and exhaust camshafts. The VANOS units were designed as integral components of the chain drive, and the adjustment ranges are 63 degrees for the intake camshaft and 60 degrees for the exhaust camshaft. The redline for the N73 is 6,500 rpm. The N73 engine also has variable valve lift (valvetronic), which varied intake valve opening lift from 0.30 - 9.85 mm, according to engine speed and load. Each cylinder head has a valvetronic assembly – including a motor, control module and position sensor. The N73 was superseded by the BMW N74, a twin-turbocharged V12 engine.

Versions

N73B60

The 5972 cc version has a bore of 89 mm and a stroke of 80 mm. Application:

N73B68

The 6749 cc version has a bore of 92 mmand a stroke of 84.6 mm. Application: