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Fiat Twin Cam engine

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Fiat Twin Cam engine
Overview
ManufacturerFiat/Lancia
Production1966–2000
Layout
ConfigurationInline-4
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)
Cylinder block materialCast iron
Cylinder head materialAluminium alloy
ValvetrainDOHC 2 or 4 valves x cyl.
Combustion
SuperchargerIn VX versions
TurbochargerIn some versions
Fuel systemCarburetor, Indirect injection, Direct injection
Fuel typeGasoline
Cooling systemWater-cooled
Chronology
SuccessorFiat Pratola Serra engine

The Fiat Twin Cam (also known as the Lampredi Twin Cam) is an advanced double overhead camshaft inline-four automobile engine produced from 1966 through 2000 as a Fiat/Lancia engine. Designed by ex Ferrari engineer Aurelio Lampredi, 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, FSO 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. It was replaced by the Fiat "family B" Pratola Serra engine series.

Design

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The Twin Cam uses the block of the overhead valve 124-series engine first found in the Fiat 124 with some modifications to accept the belt drive for the double overhead camshafts (DOHC). 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 double overhead camshaft 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 toothed rubber belt driven camshafts and aluminium alloy heads. Earlier Fiat Twin Cam engines were actually O.S.C.A. designs.

CHT

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CHT engine in a Fiat 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.

Applications

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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.

Displacements

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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; SEAT 124, SEAT 1430
1.6 L (1,585 cc) 84 mm × 71.5 mm (3.31 in × 2.81 in) Fiat 131 Supermirafiori, Fiat 132/Argenta, Fiat Ritmo 105TC; Lancia Beta, Lancia Beta Coupe/HPE, Lancia Delta/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; SEAT 124, SEAT 1430, SEAT 131, SEAT 132; 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; SEAT 124 Sport
1.8 L (1,756 cc) 84 mm × 79.2 mm (3.31 in × 3.12 in) Fiat 124 coupe/Spider, Fiat 132, Fiat Tipo/Tempra; Lancia Beta, Lancia Beta Coupe/HPE, Lancia Delta/Prisma, Lancia Dedra; SEAT 124, SEAT 124 Sport, SEAT 1430, SEAT 131, SEAT 132; Polski Fiat 125p Akropolis
1.9 L (1,920 cc) 84 mm × 86.6 mm (3.31 in × 3.41 in) SEAT 124, SEAT 131, SEAT 132
2.0 L (1,995 cc) 84 mm × 90 mm (3.31 in × 3.54 in) Fiat Spider 2000, Fiat 131, Fiat 132/Argenta, Fiat Strada/Ritmo/Regata, Fiat Croma, Fiat Tipo/Tempra, Fiat Coupé; Lancia Beta, Lancia Beta Coupe/HPE, Lancia Delta/Prisma, Lancia Dedra, Lancia Thema; SEAT 124, SEAT 131; FSO Polonez
2.1 L (2,110 cc) 85 mm × 93 mm (3.35 in × 3.66 in) Lancia 037 Evo II (also supercharged); SEAT 124-16v Gr.5 1977

Engine Codes

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Engine type Engine volume Engine power
154A2.000 1995ccm 155HP
124AC3.000 1438ccm 90HP
124AC.000 1438ccm 90HP
124AC.040 1438ccm 96HP
132A.040.4 1592ccm 95HP
132AC.000 1592ccm 95HP
132A9.000 1592ccm 98HP
132AC.040.3 1592ccm 87HP
125BC000 1608ccm 110HP
125BC040 1608ccm 110HP
132AC1.000 1756ccm 114HP/118HP
132A1.031.5 1756ccm 83HP
132A1.040.4 1756ccm 86HP
132A1.040.5 1756ccm 86HP
131A1.040 1756ccm 87HP
132AC4.000 1756ccm 128HP
132C2.040 1995ccm 83HP
132C2.031 1995ccm 87HP
132C3.031 1995ccm 102HP/105HP
132V3.031 1995ccm 135HP
125A.000 1608ccm 90HP
125B.000 1608ccm 100HP
131B.000 1297ccm 77HP
131B7.000 1301ccm 77HP
131C1.000 1367ccm 77HP
131B1.000 1585ccm 95HP/98HP
131C3.000 1585ccm 97HP
132A1.040 1756ccm 87HP
132C2.031 1995ccm 80HP
132C2.040 1995ccm 86HP
132C3.031 1995ccm 102HP
132C3.040 1995ccm 80HP/105HP
131B2.000 1995ccm 115HP
131C4.000 1995ccm 115HP
132DB.000 1995ccm 187HP
131AR.000 1995ccm 140HP/215HP
132A.000 1592ccm 98HP
132B.000 1592ccm 98HP
132C.600 1585ccm 90HP
132C.000 1585ccm 98HP
132A1.000 1756ccm 105HP
132B1.000 1756ccm 107HP/111HP
132CB.0A0 1585ccm 98HP
132C2.000 1995ccm 112HP
132D.000 1585ccm 98HP
132D1.000 1995ccm 113HP
132D4.000 1995ccm 122HP
132C3.000 1995ccm 122HP
132D7.000 1995ccm 135HP
132E.000 1995ccm 135HP
828B3.000 1297ccm 82HP
828C3.000 1301ccm 84HP
828D3.000 1367ccm 83HP
828A2.000 1438ccm 90HP
828A.000 1592ccm 100HP
828AC.000 1592ccm 108HP
828B.000 1585ccm 100HP (>82)
828B.000 1585ccm 108HP (82>)
828A1.000 1756ccm 110HP
828A1.0405 1756ccm 86HP
828AC1.000 1756ccm 120HP
134AS.600 1756ccm 82HP
134AS.0316 1756ccm 82HP
828B1.000 1995ccm 115HP (->78)
828B1.000 1995ccm 119HP (79->)
828B1.0405 1995ccm 87HP
134AS.000 1995ccm 120HP
828B4.000 1995ccm 122HP
828B4.0405 1995ccm 108HP/106HP
828B7.000 1995ccm 135HP
834C.000 1995ccm 166HP
838A4.000 1995ccm 205HP (Kappa)
? 1995ccm 205HP (037 stradale)
? 2110ccm 325HP (competition engine)

Motorsport

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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.

The Fiat Twin Cam has also been used in hot rods and kit cars, with an aftermarket kit to swap one into the Morris Minor.


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

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Footnotes

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  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). Vol. 77. Berne, Switzerland: Hallwag, AG. p. 296. ISBN 3-444-06062-9.