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Ford Zetec-R specs: 121 ci (2.0L) 4-cylinder, 3.339 x 3.465 in (84.8 x 88 mm) bore and stroke, 10.2:1 compression. Rated 170 hp, 2002–2004.
The Ford Zetec-R is close to square: 3.3386" bore against 3.4646" stroke, within 3.6%, which splits the difference between a high-revving layout and a torque layout. The 3.4646" stroke puts mean piston speed at 4,000 ft/min around 6,950 RPM, which is where a production bottom end is generally considered at its limit. Each of the 4 cylinders displaces 30.3 ci (496 cc).
10.2:1 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 Ford 121ci family, all of them 121 ci — the differences between them are in compression, heads and rating, not displacement. 3 factory variants share these dimensions, rated at 170 hp across 2002–2004.
| Displacement | 121 ci / 2 L |
|---|---|
| Bore | 3.3386" |
| Stroke | 3.4646" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 10.2:1 |
| Bore/stroke ratio | 0.964 |
| Block material | cast iron |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 170 hp |
| Years | 2002–2004 |
| Bore/stroke character | 0.964 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,465 ft/min — conservative for a street engine |
| Displacement per cylinder | 30.3 ci |
| Static compression | 10.2:1 — 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 |
|---|---|---|
| 2002 | 170 hp | Zetec-R |
| 2003 | 170 hp | Zetec-R |
| 2004 | 170 hp | Zetec-R |
1 factory vehicle, 2002–2004. Each year opens that model's engine table.