Fiat Twin Cam engine explained
Designed by Aurelio Lampredi the Fiat Twin Cam (also known as the Lampredi Twin) 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" series of engines. The engine shares a lot of parts and most dimensions with the pushrod Fiat 124 series engine (later also available with an overhead camshaft). As the name implies, it was a DOHC design, which was quite unusual in the late 1950s. The engine was produced in a large number of displacements, ranging from 1,297 cc to 1,995 cc and was used in Fiat, Lancia, Morgan and Alfa Romeo cars.
Fiat was the pioneer in engine development during the time period, using a monoblock technology, belt driven camshafts and aluminium alloy heads. Earlier Fiat Twin Cam engines were actually O.S.C.A. designs.
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.
One interesting version was the CHT (for "Controlled High Turbulence"). This was mainly used in the first generation Fiat Croma and used auxiliary intake ducts to provide a better fuel and gas mixture under low or partial acceleration. This meant considerably improved fuel mileage.
|Displacement (cc)||Bore (mm)||Stroke (mm)|
|1297||76||71.5||Lancia Beta, Fiat 131 Supermirafiori|
|1367||78||71.5||Lancia Beta, Fiat 131 Supermirafiori|
|1438||80||71.5||Fiat 124 Special T/Coupe/Spider|
|1585||84||71.5||Fiat 131 Supermirafiori/Argenta/Ritmo 105TC; Lancia Beta/Delta GT/Delta HF/Prisma|
|1592||80||79.2||Fiat 124 Special T/Coupe, Fiat 132; Lancia Beta|
|1608||80||80||Fiat 124 Coupe/Spider, Fiat 125|
|1756||84||79.2||Fiat 124 Coupe/Spider/132/Tipo/Tempra; Lancia Beta/Delta/Prisma|
|1995||84||90||Fiat Spider 2000/132/Argenta/Strada/Ritmo/Regata/Croma/Tipo/Tempra; Lancia Beta/Delta/Prisma/Thema|