Bore, stroke, displacement and compression for all 6 Nissan 122ci engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 122 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.307–3.433" |
| Stroke | 3.268–3.547" |
| Compression | 9.5–9.7:1 |
| Advertised power | 97–248 hp |
| Years | 1967–2026 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| KR20DDET | 122 ci | 3.3071" × 3.5472" | — | 241–248 |
| U20 | 122 ci | 3.4331" × 3.2677" | 9.5:1 | 135 |
| L20B | 122 ci | 3.3465" × 3.3858" | — | 97 |
| CA20E | 122 ci | 3.3268" × 3.4646" | — | — |
| MR20DD | 122 ci | 3.3071" × 3.5472" | — | 141–176 |
| MR20DE | 122 ci | 3.3071" × 3.5472" | 9.7:1 | 140 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
The family mixes oversquare and undersquare designs, so members behave quite differently despite sharing a name.
Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.