PZInz. Junior engines were manufactured by Polish industry between 1934 and 1939 for the RWD-8 training and liaison aircraft. Production was undertaken at the State Engineering Works (PZInz.) in Czechowice-Ursus, under licence from the Czechoslovak Walter factory.
In 1939, Junior production was transferred to PZL WS-2 in Rzeszow (State Aviation Works Engine Factory No. 2, located within the Central Industrial District — COP). A total of over 600 engines of this type were produced.
| Configuration | 4-cylinder, inverted inline |
| Cooling | air |
| Compression ratio | 5.2 |
| Displacement | 5.8 l |
| Weight | 148 kg |
| Maximum power | 120 hp at 2300 rpm |
| Rated power | 110 hp at 2100 rpm |
