The Cummins C Series engine is a straight-six diesel engine with a displacement of 8.3 litres (506.5 cu in). Cummins began producing the engines in 1985 as the 6C8.3. The first electronic version, known as the C8.3E and designed for the urban bus market exclusively, went into production in late 1996. The ISC was introduced in 1998 and used a CAPS electronically controlled injection system along with a 24 valve head, vs 12 valves on the 6C8.3.