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Mercury Duratec 23 specs: 140 ci (2.3L) 4-cylinder, 3.781 x 3.126 in (96 x 79.4 mm) bore and stroke, 9.7:1 compression. Rated 160 hp, 2006–2009. SOHC.
The Mercury Duratec 23 is oversquare — the 3.781" bore exceeds the 3.126" stroke by 21.0% — a layout that favors airflow and RPM over leverage at the crank. The 3.126" stroke does not reach 4,000 ft/min of mean piston speed until about 7,700 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.665 is in the range most production engines fall in. Each of the 4 cylinders displaces 35.0 ci (574 cc).
9.7:1 on iron heads is in the range that usually runs on pump premium; iron holds heat, so treat it as the less forgiving side of that range.
4 factory variants share these dimensions, rated at 160 hp across 2006–2009.
| Displacement | 140 ci / 2.3 L |
|---|---|
| Bore | 3.781" |
| Stroke | 3.126" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 9.7:1 |
| Rod length | 5.205" |
| Rod ratio | 1.665 |
| Bore/stroke ratio | 1.21 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | SOHC |
| Fuel type | gas |
| Advertised HP | 160 hp |
| Years | 2006–2009 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2006 | net | 160 @ 6250 * | 156 lb-ft @ 4250 * | — |
| 2008 | net | 160 @ 6250 | 156 lb-ft @ 4250 | 9.7:1 |
Factory specification sheet. * Not yet cross-verified.
| Bore/stroke character | 1.210 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,126 ft/min — conservative for a street engine |
| Rod ratio | 1.665 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 35.0 ci |
| Static compression | 9.7:1 — 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 |
|---|---|---|
| 2006 | 160 hp | Duratec 23 |
| 2007 | 160 hp | Duratec 23 |
| 2008 | 160 hp | Duratec 23 |
| 2009 | 160 hp | Duratec 23 |