Designed by ex Ferrari engineer Aurelio Lampredi, the Fiat Twin Cam (also known as the Lampredi Twin Cam) was an advanced inline-four automobile engine produced from 1966 through 2000 as a Fiat/Lancia engine until it was replaced by the "family B" Pratola Serra engine series. The engine was produced in a large number of displacements, ranging from and was used in Fiat, Lancia, Alfa Romeo, SEAT and Morgan cars. The Fiat Twin Cam engine has been widely used in motorsport and has been the most successful engine in the history of the World Rally Championship. Fiat and Lancia won a total of ten World Rally Championships for Manufacturers using engines based on the Lampredi Twin Cam engine. Design The engine uses the block of the OHV 124-series unit first found in the Fiat 124 with some modifications to accept the belt drive for the camshafts. The head itself is made in three pieces, one carrying the combustion chamber and valves and one separate casting for each camshaft in tunnel type bearings. The valves had an included angle of 65 degrees. The engine featured a revolutionary new method for adjusting the valve clearance. Usually at that time in DOHC engines like from Alfa Romeo or Jaguar, small shims were placed on the valve stem inside the bucket tappets, thereby necessitating the removal of the camshafts to get access to these shims to adjust the valve clearance, making for time consuming and very expensive maintenance work. Lampredi’s design placed the shims on top of the tappets where they could be removed with the camshaft in situ after the tappets were pressed down with a special tool. This design was patented for Fiat and was used in the engines of the 128 and 130, and even the Ferrari/Fiat Dino V6 engine was converted to this system. Fiat was a pioneer in engine development during the time period, using belt driven camshafts and aluminium alloy heads. Earlier Fiat Twin Cam engines were actually O.S.C.A. designs. Applications Lampredi's twin cam engine was first seen in the Fiat 124 coupé of late 1966, but was later made available in a large number of cars. Fiat 1966-1974 124 Sport coupé 1966-1985 124 Sport Spider 1970-1974 124 Special T 1972-1976 124 Abarth Rally 1967-1972 125 1972-1981 132 1981-1985 Argenta 1977-1983 131 1977-1980 131 Abarth 1982-1988 Ritmo 1984-1989 Ritmo 105TC, 125TC, 130TC 1983-1990 Regata 1985-1996 Croma 1988-1995 Tipo 1990-1999