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Mercedes-Benz M117 specs: 4.5L (276 ci) 8-cylinder, 92 x 85 mm (3.6220 x 3.3465 in) bore and stroke, 8:1 compression. Rated 190 hp, 1972–1980.
The Mercedes-Benz M117 is oversquare — the 3.622" bore exceeds the 3.3465" stroke by 8.2% — a layout that favors airflow and RPM over leverage at the crank. The 3.3465" stroke does not reach 4,000 ft/min of mean piston speed until about 7,150 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 8 cylinders displaces 34.5 ci (565 cc).
8:1 is low by modern standards and generally happy on regular pump fuel.
11 factory variants share these dimensions, rated at 190 hp across 1972–1980.
| Displacement | 276 ci / 4.5 L |
|---|---|
| Bore | 3.622" |
| Stroke | 3.3465" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 8:1 * |
| Bore/stroke ratio | 1.082 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Advertised HP | 190 hp |
| Years | 1972–1980 |
| Bore/stroke character | 1.082 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,347 ft/min — conservative for a street engine |
| Displacement per cylinder | 34.5 ci |
| Static compression | 8:1 — low by modern standards, generally happy on regular pump fuel |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1972 | — | M117 |
| 1973 | — | M117 |
| 1973 | 190 hp | M117 |
| 1974 | — | M117 |
| 1974 | 190 hp | M117 |
| 1975 | — | M117 |
| 1976 | — | M117 |
| 1977 | — | M117 |
| 1978 | — | M117 |
| 1979 | — | M117 |
| 1980 | — | M117 |
2 factory vehicles, 1972–1980. Each year opens that model's engine table.