Fiat Twin Cam engine

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Fiat Twin Cam engine
Locust Fiat.JPG
Displacement1.3–2.0 L (1,297–1,995 cc)
Cylinder bore
  • 76 mm (2.99 in)
  • 76.1 mm (3.00 in)
  • 78 mm (3.07 in)
  • 80 mm (3.15 in)
  • 82.6 mm (3.25 in)
  • 84 mm (3.31 in)
Piston stroke
  • 71.5 mm (2.81 in)
  • 79.2 mm (3.12 in)
  • 80 mm (3.15 in)
  • 90 mm (3.54 in)
Block materialCast iron
Head materialAluminium alloy
ValvetrainDOHC 2 or 4 valves x cyl.
TurbochargerIn some versions
Fuel systemIndirect injection, Direct injection
Fuel typeGasoline
Cooling systemWater-cooled
Successor"family B" Pratola Serra

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 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. The engine was produced in a large number of displacements, ranging from 1.3 to 2.0 L (1,297 to 1,995 cc) 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. The World Rally Championship for Manufacturers has been won by Fiat and Lancia, using engines based on the Lampredi Twin Cam engine, for a total of 10 years.

Fiat was the pioneer in engine development during the time period, using a monoblock technology, belt driven camshafts and aluminium alloy heads.[citation needed] Earlier Fiat Twin Cam engines were actually O.S.C.A. designs. Despite being SOHC designs, the diesel 1.9 L (1,929 cc) (both the regular indirect-injected unit and the direct-injected one, the first direct-injection diesel appeared in a production passenger car, the Fiat Croma Turbo D i.d.) and 1.7 L (1,698 cc) blocks are both derived from the Lampredi Twin Cam.


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 CHT engine in a Croma

One version was the CHT (for "Controlled High Turbulence"). This version was mainly used in the first generation Fiat Croma and used a special head and intake with auxiliary intake ducts to provide a better fuel and gas mixture under low or partial acceleration.[1] This meant considerably improved fuel mileage.


Displacement Bore x Stroke Models
1.3 L (1,297 cc) 76 mm × 71.5 mm (2.99 in × 2.81 in) Lancia Beta, Fiat 131 Supermirafiori[citation needed]
1.3 L (1,301 cc) 76.1 mm × 71.5 mm (3.00 in × 2.81 in) Lancia Beta[citation needed]
1.4 L (1,367 cc) 78 mm × 71.5 mm (3.07 in × 2.81 in) Fiat 131 Supermirafiori[2]
1.4 L (1,438 cc) 80 mm × 71.5 mm (3.15 in × 2.81 in) Lancia Beta; Fiat 124 Special T/coupe/Spider
1.6 L (1,585 cc) 84 mm × 71.5 mm (3.31 in × 2.81 in) Fiat 131 Supermirafiori/132/Argenta/Ritmo 105TC; Lancia Beta/Delta GT/Delta HF/Prisma
1.6 L (1,592 cc) 80 mm × 79.2 mm (3.15 in × 3.12 in) Fiat 124 Special T/coupe/Spider, Fiat 132; Lancia Beta, Polski Fiat 125p Monte Carlo
1.6 L (1,608 cc) 80 mm × 80 mm (3.15 in × 3.15 in) Fiat 124 coupe/Spider, Fiat 125
1.7 L (1,698 cc) 82.6 mm × 79.2 mm (3.25 in × 3.12 in) Fiat Duna/Fiorino/Ritmo/Regata/Uno (turbo) diesel
1.8 L (1,756 cc) 84 mm × 79.2 mm (3.31 in × 3.12 in) Fiat 124 coupe/Spider, Fiat 132/Tipo/Tempra; Lancia Beta/Delta/Prisma/Dedra, Polski Fiat 125p Akropolis
1.9 L (1,929 cc) 82.6 mm × 90 mm (3.25 in × 3.54 in) Fiat Bravo/Brava/Croma/Ducato/Ritmo/Regata/Tipo/Tempra; Lancia Delta/Dedra/Prisma (turbo) diesel[3]
2.0 L (1,995 cc) 84 mm × 90 mm (3.31 in × 3.54 in) Fiat Spider 2000/131/132/Argenta/Strada/Ritmo/Regata/Croma/Tipo/Tempra/coupé; Lancia Beta/Delta/Prisma/Dedra/Thema, FSO Polonez


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. The World Rally Championship for Manufacturers has been won by Fiat and Lancia, using engines based on the Lampredi Twin Cam engine, for a total of 10 years.

The four valve version made its first appearance in the Group 4 competition version of the Fiat 124 Spider Abarth, where it had 1.8 litres. Group 4 regulations at that time allowed the use of a cylinder head of a "free" design. This engine still used a three-piece cylinder head design with an included valve angle of 46 degrees.

In later years motorsport regulations were changed so that the use of four valve heads was only possible when the homologated cars had four valve heads. Therefore, the homologation series of the Fiat 131 Rally Abarth came with a two-litre version of the four valve engine.

These engines were later used in the mid-engined Lancia 037, where they were supercharged and eventually enlarged to 2.1 litres.

In addition to the titles in the World Rally Championship, the Fiat Twin Cam equipped the Lancia Beta Montecarlo turbo, that won the World Sportscar Championship for two consecutive seasons in 1980-1981.

Fiat 131 Abarth of Walter Röhrl at 1980 Rallye Sanremo
Constructor Car used in World Championship Seasons Manufacturers' titles
Italy Fiat Fiat 124 Abarth 1970–1975
Italy Lancia Lancia Beta coupe 1974–1975
Italy Fiat Fiat 131 Abarth 1976–1982 3 (1977, 1978, 1980)
Italy Lancia Lancia 037 1982–1986 1 (1983)
Italy Lancia Lancia Delta HF 4WD and Delta Integrale 1987–1993 6 (1987–1992)

See also[edit]


  1. ^ "CHT". Dizionario Tecnico dell'Automobilismo [Technical Automotive Dictionary] (in Italian). Archived from the original on 2013-06-10. Retrieved 2013-05-01.
  2. ^ Büschi, Hans-Ulrich, ed. (March 3, 1982). "Automobil Revue '82" (in German and French). 77. Berne, Switzerland: Hallwag, AG: 296. ISBN 3-444-06062-9. Cite journal requires |journal= (help)
  3. ^ "Fiat Tempra 1.9 Tds Turbo-diesel" (PDF).