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Nissan SD25 specs: 2.5L (152 ci) 4-cylinder, 89 x 100 mm (3.5039 x 3.9370 in) bore and stroke. Built 1984–1985. Used in the Nissan Datsun / Nissan Pickup.
The Nissan SD25 is undersquare — the 3.937" stroke exceeds the 3.5039" bore by 11.0% — a layout that trades peak RPM for leverage and torque low in the range. The 3.937" stroke puts mean piston speed at 4,000 ft/min around 6,100 RPM, which is where a production bottom end is generally considered at its limit. Each of the 4 cylinders displaces 38.0 ci (623 cc).
It is one of 4 engines in the Nissan 152ci family, all of them 152 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions across 1984–1985.
| Displacement | 152 ci / 2.5 L |
|---|---|
| Bore | 3.5039" |
| Stroke | 3.937" |
| Cylinders | 4 |
| Configuration | I4 |
| Bore/stroke ratio | 0.89 |
| Fuel type | diesel |
|---|---|
| Years | 1984–1985 |
| Bore/stroke character | 0.890 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,937 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 38.0 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 |
|---|---|---|
| 1984 | — | SD25 |
| 1985 | — | SD25 |
1 factory vehicle, 1984–1985. Each year opens that model's engine table.