See other engines in this family
Mercedes-Benz M117 specs: 5.5L (339 ci) 8-cylinder, 96.5 x 94.8 mm (3.7992 x 3.7323 in) bore and stroke. Built 1986–1989. Used in the Mercedes-Benz SL.
The Mercedes-Benz M117 is close to square: 3.7992" bore against 3.7323" stroke, within 1.8%, which splits the difference between a high-revving layout and a torque layout. The 3.7323" stroke puts mean piston speed at 4,000 ft/min around 6,450 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 42.4 ci (694 cc).
It is one of 2 engines in the Mercedes-Benz 339ci family, all of them 339 ci — the differences between them are in compression, heads and rating, not displacement. 4 factory variants share these dimensions across 1986–1989.
| Displacement | 339 ci / 5.5 L |
|---|---|
| Bore | 3.7992" |
| Stroke | 3.7323" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 9–10:1 (published figures vary) |
| Bore/stroke ratio | 1.018 |
| Fuel type | gas |
|---|---|
| Years | 1986–1989 |
| Bore/stroke character | 1.018 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,732 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 42.4 ci |
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 |
|---|---|---|
| 1986 | — | M117 |
| 1987 | — | M117 |
| 1988 | — | M117 |
| 1989 | — | M117 |
1 factory vehicle, 1986–1989. Each year opens that model's engine table.