Vauxhall Slant-4 engine

The Vauxhall Slant-4 (or Slant Four) is an inline four-cylinder petrol car engine manufactured by Vauxhall Motors. Unveiled in 1966, it was one of the first production overhead camshaft designs to use a timing belt to drive the camshaft. The Slant-4 block was used as a development mule for the Lotus 900 series of engines. Vauxhall used the engine in a variety of models until production ended in 1983. History Design The Slant-4 gets its name from the fact that its cylinders are inclined at an angle of approximately 45° from vertical. This layout came about because Vauxhall had originally planned to develop a whole family of engines all built on the same production line. There were to be slant-4s and V8s in both petrol and diesel versions, designed under the guidance of Vauxhall's then chief engineer, John Alden. Although a V8 petrol prototype and several 4-cylinder diesel prototypes were built only the 4-cylinder petrol engine made it to series production. The engine has a single overhead camshaft driven by a timing belt. The Slant-4 was one of three engines using this method of driving the camshaft released the same year, the others being the Fiat Twin Cam engine and the Pontiac straight-6 OHC. Prior to 1966, belt-driven camshafts had only appeared in the Glas 1004 series starting in 1962 and in the few Devin-Panhard cars built starting in 1956. The camshaft operated two valves per cylinder. An ingenious valve train design incorporating an inclined socket head cap screw allowed valve clearances to be adjusted with a feeler gauge and an Allen key. The block and crossflow head are both of cast iron. The layout lowers the overall height of the engine, which allowed for more aerodynamic vehicle bodies to be achieved by lowering the bonnet line. It also means most of the engine is very easy to access for maintenance, with the exception of the exhaust manifold and spark plugs, which are "underneath" the slanted cylinders.