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Mercedes-Benz M157 specs: 5.5L (333 ci) 8-cylinder, 98 x 90.5 mm (3.8583 x 3.5630 in) bore and stroke, 10:1 compression. Rated 518-577 hp, 2011–2019.
The Mercedes-Benz M157 is oversquare — the 3.8583" bore exceeds the 3.563" stroke by 8.3% — a layout that favors airflow and RPM over leverage at the crank. The 3.563" stroke puts mean piston speed at 4,000 ft/min around 6,750 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 41.6 ci (682 cc).
10:1 is in the range that usually runs on pump premium.
It is one of 2 engines in the Mercedes-Benz 333ci family, all of them 333 ci — the differences between them are in compression, heads and rating, not displacement. 12 factory variants share these dimensions, rated from 518 to 577 hp across 2011–2019.
| Displacement | 333 ci / 5.5 L |
|---|---|
| Bore | 3.8583" |
| Stroke | 3.563" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 10:1 |
| Bore/stroke ratio | 1.083 |
| Fuel type | gas |
|---|---|
| Advertised HP | 518–577 hp |
| Years | 2011–2019 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2016 | M157 net | 577 @ 5500 | 561 lb-ft @ 1750-5250 | 10:1 |
Factory specification sheet.
| Bore/stroke character | 1.083 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,563 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 41.6 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.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 2011 | — | M157 |
| 2012 | — | M157 |
| 2012 | 518 hp | M157 |
| 2013 | — | M157 |
| 2013 | 518 hp | M157 |
| 2014 | — | M157 |
| 2015 | — | M157 |
| 2016 | — | M157 |
| 2016 | 577 hp | M157 |
| 2017 | — | M157 |
| 2018 | — | M157 |
| 2019 | — | M157 |
4 factory vehicles, 2011–2019. Each year opens that model's engine table.