Complex sentence: The Nessonvaux factory began producing Impéria-Abadals from about 1916; in 1921, it built three ohc 5.6-litre straight-eights.
Split into simpler sentences: The Nessonvaux factory began producing Impéria-Abadals from about 1916. In 1921, it built three ohc 5.6-litre straight-eights.