Bore, stroke, displacement and compression for all 2 Nissan 79ci engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 79 ci |
|---|---|
| Cylinders | 4 |
| Bore | 2.874" |
| Stroke | 3.031–3.055" |
| Compression | 8.5:1 |
| Advertised power | 75 hp |
| Years | 1966–1974 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| A13 | 79 ci | 2.874" × 3.0315" | 8.5:1 | 75 |
| J13 | 79 ci | 2.874" × 3.0551" | — | — |
Every engine here shares a 2.874" bore; displacement varies by stroke alone, which is the signature of a family built on one block with different cranks.
All are undersquare — stroke larger than bore, favouring torque low in the range.
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.