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Mercury 4.0 SOHC Cologne specs: 245 ci (4.0L) 6-cylinder, 3.953 x 3.323 in (100.4 x 84.4 mm) bore and stroke. Rated 210 hp, 2005–2010. SOHC.
The Mercury 4.0 SOHC Cologne is oversquare — the 3.9528" bore exceeds the 3.3228" stroke by 19.0% — a layout that favors airflow and RPM over leverage at the crank. The 3.3228" stroke does not reach 4,000 ft/min of mean piston speed until about 7,200 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 40.8 ci (669 cc).
It is one of 10 engines in the Cologne family, sitting between the 170 ci and 256 ci members. 6 factory variants share these dimensions, rated at 210 hp across 2005–2010.
| Displacement | 245 ci / 4 L |
|---|---|
| Bore | 3.9528" |
| Stroke | 3.3228" |
| Cylinders | 6 |
| Configuration | V6 |
| Bore/stroke ratio | 1.19 |
| Block material | cast iron |
|---|---|
| Head material | aluminum |
| Valvetrain | SOHC |
| Fuel type | gas |
| Advertised HP | 210 hp |
| Years | 2005–2010 |
| Bore/stroke character | 1.190 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,323 ft/min — conservative for a street engine |
| Displacement per cylinder | 40.8 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 |
|---|---|---|
| 2005 | 210 hp | 4.0 SOHC Cologne |
| 2006 | 210 hp | 4.0 SOHC Cologne |
| 2007 | 210 hp | 4.0 SOHC Cologne |
| 2008 | 210 hp | 4.0 SOHC Cologne |
| 2009 | 210 hp | 4.0 SOHC Cologne |
| 2010 | 210 hp | 4.0 SOHC Cologne |