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Nissan J13 specs: 1.3L (79 ci) 4-cylinder, 73 x 77.6 mm (2.8740 x 3.0551 in) bore and stroke. Built 1966–1968. Used in the Nissan Datsun / Nissan Pickup.
The Nissan 79ci (J13) is undersquare — the 3.0551" stroke exceeds the 2.874" bore by 5.9% — a layout that trades peak RPM for leverage and torque low in the range. The 3.0551" stroke does not reach 4,000 ft/min of mean piston speed until about 7,850 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 19.8 ci (324 cc).
It is one of 2 engines in the Nissan 79ci family, all of them 79 ci — the differences between them are in compression, heads and rating, not displacement. 3 factory variants share these dimensions across 1966–1968.
| Displacement | 79 ci / 1.3 L |
|---|---|
| Bore | 2.874" |
| Stroke | 3.0551" |
| Cylinders | 4 |
| Configuration | I4 |
| Bore/stroke ratio | 0.941 |
| Fuel type | gas |
|---|---|
| Years | 1966–1968 |
| Bore/stroke character | 0.941 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,055 ft/min — conservative for a street engine |
| Displacement per cylinder | 19.8 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 |
|---|---|---|
| 1966 | — | J13 |
| 1967 | — | J13 |
| 1968 | — | J13 |
1 factory vehicle, 1966–1968. Each year opens that model's engine table.