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Nissan RB specs: 2.0L (121.8 ci) 6-cylinder, 78 x 69.7 mm (3.0709 x 2.7441 in) bore and stroke, 9.5:1 compression. Rated 128-153 hp. SOHC.
The Nissan RB is oversquare — the 3.0709" bore exceeds the 2.7441" stroke by 11.9% — a layout that favors airflow and RPM over leverage at the crank. The 2.7441" stroke does not reach 4,000 ft/min of mean piston speed until about 8,750 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 20.3 ci (333 cc).
9.5:1 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 11 engines in the RB family, the smallest at 121.8 ci. 2 factory variants share these dimensions, rated from 128 to 153 hp. Factory fitments include the Nissan Skyline R31, Nissan Laurel C32, Nissan Cefiro A31 and 2 others.
| Displacement | 121.8 ci / 2 L |
|---|---|
| Bore | 3.0709" |
| Stroke | 2.7441" |
| Cylinders | 6 |
| Compression ratio | 9.5:1 |
| Bore/stroke ratio | 1.119 |
| Block material | cast iron |
|---|---|
| Head material | aluminum |
| Valvetrain | SOHC |
| Fuel type | gas |
| Advertised HP | 128–153 hp |
| Bore/stroke character | 1.119 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,744 ft/min — conservative for a street engine |
| Displacement per cylinder | 20.3 ci |
| Static compression | 9.5:1 — 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 |
|---|---|---|
| — | 128 hp | RB20E |
| — | 153 hp | RB20DE |