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Mercedes-Benz M104.942 specs: 2.8L (171 ci) 6-cylinder, 89.9 x 73.5 mm (3.5394 x 2.8937 in) bore and stroke, 10:1 compression. Built 1993.
The Mercedes-Benz M104.942 is oversquare — the 3.5394" bore exceeds the 2.8937" stroke by 22.3% — a layout that favors airflow and RPM over leverage at the crank. The 2.8937" stroke does not reach 4,000 ft/min of mean piston speed until about 8,300 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 28.5 ci (467 cc).
10:1 is in the range that usually runs on pump premium.
It is one of 3 engines in the Mercedes-Benz 171ci family, all of them 171 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 171 ci / 2.8 L |
|---|---|
| Bore | 3.5394" |
| Stroke | 2.8937" |
| Cylinders | 6 |
| Configuration | I6 |
| Compression ratio | 10:1 * |
| Bore/stroke ratio | 1.223 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Years | 1993 |
| Bore/stroke character | 1.223 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,894 ft/min — conservative for a street engine |
| Displacement per cylinder | 28.5 ci |
| Static compression | 10:1 — in the range that usually runs on pump premium |
Each link opens the calculator with this engine's specs already filled in.
1 factory vehicle, 1993. Each year opens that model's engine table.