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Lincoln 25 Duratec V6 specs: 155.2 ci (2.5L) 6-cylinder, 3.244 x 3.13 in (82.4 x 79.5 mm) bore and stroke, 10:1 compression. Rated 170 hp. DOHC.
The Lincoln 25 Duratec V6 is close to square: 3.2441" bore against 3.1299" stroke, within 3.6%, which splits the difference between a high-revving layout and a torque layout. The 3.1299" stroke does not reach 4,000 ft/min of mean piston speed until about 7,650 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 25.9 ci (424 cc).
10:1 on aluminum heads is in the range that usually runs on pump premium; aluminum sheds heat faster than iron, which makes the same number a little more forgiving.
It is one of 5 engines in the Duratec family, sitting between the 152 ci and 227 ci members. Factory fitments include the Lincoln LS.
| Displacement | 155.2 ci / 2.5 L |
|---|---|
| Bore | 3.2441" |
| Stroke | 3.1299" |
| Cylinders | 6 |
| Compression ratio | 10:1 |
| Bore/stroke ratio | 1.036 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 170 hp |
| Bore/stroke character | 1.036 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,130 ft/min — conservative for a street engine |
| Displacement per cylinder | 25.9 ci |
| Static compression | 10:1 — in the range that usually runs on pump premium |
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