See other engines in this family
Mazda UC specs: 1.4L (86 ci) 4-cylinder, 77 x 76 mm (3.0315 x 2.9921 in) bore and stroke. Rated 65 hp, 1979. Used in the Mazda GLC / 323.
The Mazda 86ci (UC) is close to square: 3.0315" bore against 2.9921" stroke, within 1.3%, which splits the difference between a high-revving layout and a torque layout. The 2.9921" stroke does not reach 4,000 ft/min of mean piston speed until about 8,000 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 21.5 ci (352 cc).
| Displacement | 86 ci / 1.4 L |
|---|---|
| Bore | 3.0315" |
| Stroke | 2.9921" |
| Cylinders | 4 |
| Configuration | I4 |
| Bore/stroke ratio | 1.013 |
| Fuel type | gas |
|---|---|
| Advertised HP | 65 hp |
| Years | 1979 |
| Bore/stroke character | 1.013 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 2,992 ft/min — conservative for a street engine |
| Displacement per cylinder | 21.5 ci |
Each link opens the calculator with this engine's specs already filled in.
1 factory vehicle, 1979. Each year opens that model's engine table.