M166

The W 168 A-Class fitted a full-height cabin onto a 3.6-meter footprint by raising the floor and hiding the mechanicals beneath it — the sandwich concept — and that only worked if the engine went where it was told. The M 166 was mounted transversely just behind the front axle and laid over at 59° from vertical, so that a heavy frontal impact would drive it down the inclined bulkhead and beneath the occupants’ feet instead of through the pedals. Aluminum block, aluminum head, one chain-driven camshaft, two valves per cylinder: compact before anything else.

Four capacities followed between 1997 and 2005 — 1.4, 1.6, 1.9 and the 2.1 of the A 210 Evolution — all on the same eight-valve architecture, running compression ratios as high as 11:1 to keep the smaller ones drivable without forced induction. The Vaneo, a tall five-seat van on A-Class underpinnings, took the 1.6 and 1.9 from 2002. When the W 169 A-Class arrived in 2004 the M 266 replaced it, and the last M 166s left with the Vaneo the following year.