How can you tell a motor with Vanos from a non-Vanos motor just by looking?

[Jon K]

... lol... ok?

[shogun]

The VANOS unit is readily identifiable by the "lump" on the driver's side of the head & valve cover at the front of the engine. The VANOS unit adjusts the timing of the intake cam.

Newer BMWs, such as the E46 M3, with "twin VANOS" motors (VANOS units controlling both the intake and exhaust cams) have a "lump" on both sides of the valve cover.

http://www.bimmerhaus.com/tech/vanos.html