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Nissan L20B specs: 2.0L (122 ci) 4-cylinder, 85 x 86 mm (3.3465 x 3.3858 in) bore and stroke. Rated 97 hp, 1977–1979. Used in the Nissan 200SX.
The Nissan L20B is close to square: 3.3465" bore against 3.3858" stroke, within 1.2%, which splits the difference between a high-revving layout and a torque layout. The 3.3858" stroke does not reach 4,000 ft/min of mean piston speed until about 7,100 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 30.5 ci (500 cc).
It is one of 6 engines in the Nissan 122ci family, all of them 122 ci — the differences between them are in compression, heads and rating, not displacement. 3 factory variants share these dimensions, rated at 97 hp across 1977–1979.
| Displacement | 122 ci / 2 L |
|---|---|
| Bore | 3.3465" |
| Stroke | 3.3858" |
| Cylinders | 4 |
| Configuration | I4 |
| Bore/stroke ratio | 0.988 |
| Fuel type | gas |
|---|---|
| Advertised HP | 97 hp |
| Years | 1977–1979 |
| Bore/stroke character | 0.988 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,386 ft/min — conservative for a street engine |
| Displacement per cylinder | 30.5 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 |
|---|---|---|
| 1977 | 97 hp | L20B |
| 1978 | 97 hp | L20B |
| 1979 | — | L20B |
1 factory vehicle, 1977–1978. Each year opens that model's engine table.