Saturn I4 engine

The Saturn I4 engine was the straight-four aluminum piston engine that Saturn, a General Motors subsidiary, built for its S-Series cars. It was fitted only to the SL, SC and SW models from 1991 through 2002 and came as a chain-driven single or double overhead camshaft engine, with both versions sharing one block. It was an innovative engine for its time because the block and cylinder head were made by the lost foam casting process, which Saturn was among the first to use in full-scale high-volume production. The block was water-cooled aluminum with iron liners, the crankshaft ran on five main bearings, and the single cam LK0 and L24 engines made 85 to 100 horsepower while the twin cam LL0 made 124. Some cylinder heads of the single cam engine cracked near the fifth camshaft journal, and Saturn extended the head warranty for that fault.