Volkswagen air-cooled engine

Volkswagen E-motor
Manufacturer Volkswagen
Production 1936–2006
Combustion chamber
Configuration Flat-4 naturally aspirated petrol engine
Cylinder block alloy Aluminum / magnesium alloy
Cylinder head alloy Aluminum / magnesium alloy
Valvetrain Pushrod OHV
Fuel system Mechanical / Carbureted
Fuel type Gasoline
Oil system Wet sump
Cooling system Air-cooled

The Volkswagen air-cooled engine is an air-cooled boxer engine with four horizontally opposed cast-iron cylinders, cast aluminum alloy cylinder heads and pistons, magnesium crankcase, and forged steel crankshaft and connecting rods.

Variations of the engine were produced by Volkswagen plants worldwide from 1936 until 2006 for use in Volkswagen's own vehicles, notably the Type 1 (Beetle), Type 2 (bus, transporter), Type 3, and Type 4. Additionally, the engines were widely used in industrial, light aircraft and kit car applications.

Type 1: 1.0–1.6 litres

Volkswagen Type 1 engine
Fuel system Carburetor
Successor Volkswagen Type 4 engine
Volkswagen 1000 engine
Production 1938–1942
Combustion chamber
Displacement 985 cc (60.1 cu in)
Cylinder bore 70 mm (2.76 in)
Piston stroke 64 mm (2.52 in)
Compression ratio 5.8:1
Power output 18 kW (24 PS; 24 bhp) @ 3,000 rpm,
22 kW (30 PS; 30 bhp)
Volkswagen 1100 engine
Production 1945–1953
Combustion chamber
Displacement 1,131 cc (69.0 cu in)
Cylinder bore 75 mm (2.95 in)
Piston stroke 64 mm (2.52 in)
Compression ratio 5.8:1
Power output 18 kW (24 PS; 24 bhp) @ 3,300 rpm,
22 kW (30 PS; 30 bhp)
Specific power 15.9 kW (22 PS; 21 bhp) / L (18kW variant)
Torque output 68 N·m (50 lbf·ft) @ 2,000 rpm
Volkswagen Typ 122[1]
Production 1950–1991
Combustion chamber
Displacement 1,192 cc (72.7 cu in)
Cylinder bore 77 mm (3.03 in)
Piston stroke 64 mm (2.52 in)
Compression ratio 7.0:1 – 7.3:1
Fuel system Carburettor
Solex 28 PCI or Solex 28 PICT
Fuel type Carburettor fuel
86 RON (7:1 compression ratio)
87 RON (7,3:1 compression ratio)
Power output 22 kW (30 PS; 30 bhp)
25 kW (34 PS; 34 bhp)
27 kW (37 PS; 36 bhp)
30 kW (41 PS; 40 bhp)
Specific power 18.5–21.0 kW (25–29 PS; 25–28 bhp) / L
Torque output depending on engine application, around ~70–80 N·m
Volkswagen 1300 engine
Production 1966–1995
Volkswagen 1500 engine
Production 1961–1971
Combustion chamber
Displacement 1,493 cc (91.1 cu in)
Cylinder bore 83 mm (3.27 in)
Piston stroke 69 mm (2.72 in)
Power output 1500N: 33 kW (45 PS; 44 bhp),
1500S: 40 kW (54 PS; 54 bhp)
Specific power 22.1–26.8 kW (30–36 PS; 30–36 bhp) / L
Volkswagen Typ 126[1]
Combustion chamber
Displacement 1584 cm3
Cylinder bore 85,5 mm
Piston stroke 69 mm
Compression ratio 7,7:1
Fuel system Carburettor
Solex 30 PICT II or Solex 34 PCI
Fuel type Carburettor fuel 90 RON
Power output With governor, 8 % accuracy:
28,7 kW at 3000 min1
without governor:
30,9 kW at 3000 min1[2]
Torque output With governor, 8 % accuracy:
98 N·m at at 2000 min1
without governor:
108,9 N·m at 2000 min1[2]
Dry weight 100 kg

Like the Volkswagen Beetle produced after the war, the first Volkswagen Transporters (bus) used the Volkswagen air-cooled engine, a 1.1 litre, DIN-rated 18 kW (24 PS, 24 bhp), air-cooled four-cylinder "boxer" engine mounted in the rear. The 22-kilowatt (29 PS; 29 bhp) version became standard in 1955, while an unusual early version of the engine which developed 25 kilowatts (34 PS; 34 bhp) debuted exclusively on the Volkswagen Type 2 (T1) in 1959. Any examples that retain that early engine today are true survivors – since the 1959 engine was totally discontinued at the outset, no parts were ever made available.

The second-generation Transporter, the Volkswagen Type 2 (T2) employed a slightly larger version of the engine with 1.6 litres and 35 kilowatts (48 PS; 47 bhp).

A "T2b" Type 2 was introduced by way of gradual change over three years. The 1971 Type 2 featured a new, 1.6-litre engine, now with dual intake ports on each cylinder head, and was DIN-rated at 37 kilowatts (50 PS; 50 bhp).

The Volkswagen Type 3 (saloon/sedan, notch-back, fastback) was initially equipped with a 1.5-litre engine, displacing 1,493 cubic centimetres (91.1 cu in), based on the air-cooled flat-4 found in the Type 1. While the long block remained the same as the Type 1, the engine cooling was redesigned reducing the height of the engine profile, allowing greater cargo volume, and earning the nicknames of "Pancake" or "Suitcase" engine. This engine's displacement would later increase to 1.6 litres.

Originally a single- or dual-carburetor 1.5-litre engine (1500N, 33 kilowatts (45 PS; 44 bhp) or 1500S, 40 kilowatts (54 PS; 54 bhp)), the Type 3 engine received a larger displacement (1.6 litre) and modified in 1968 to include Bosch D-Jetronic electronic fuel injection as an option, making it the first mass-production consumer cars with such a feature (some sports/luxury cars with limited production runs previously had fuel injection).




The 1,2 l engine is called Typ 122 and has a displacement of 1192 cm3.[1] As industrial engine, it's rated power is 22,8 kW at 3000 min1 without a governor, the highest torque 81,4 N·m at 2000 min1. With a governor set to 8% accuracy, the rated power is 21,33 kW at 3000 min1, the highest torque is 69,63 N·m at 2000 min1.[2] For other applications, the power and torque output may vary.


1285cc Single port 1965-1970 Twin port 1971-1975


1493cc Single port only. 1967–1970 in Euro/US Beetle.


The 1,6 l engine is called Typ 126. It has a displacement of 1584 cm3.

Single port

The 1600 single port was used on the following models:

Twin port

The 1600 dual port was used on the following models:

Type 4: 1.7–2.0 litres

Volkswagen Type 4 engine
Production 1968–1983
Predecessor Volkswagen Type 1 engine
Successor Volkswagen Wasserboxer engine
Volkswagen 1700 engine
Combustion chamber
Displacement 1,679 cc (102.5 cu in)
Compression ratio 7.8:1
Power output 76 PS (56 kW) @ 5,000 rpm
Torque output 127 N·m (94 lbf·ft) @ 3,500 rpm
Volkswagen 1800 engine
Power output 50 kW (68 PS; 67 bhp)
Volkswagen 2000 engine
Power output 52 kW (71 PS; 70 bhp)

In 1968, Volkswagen introduced a new vehicle, the Volkswagen Type 4. The model 411, and later the model 412, offered many new features to the Volkswagen lineup.

While the Type 4 was discontinued in 1974 when sales dropped, its engine became the power plant for Volkswagen Type 2s produced from 1972 to 1979: it continued in modified form in the later Vanagon which was air-cooled from 1980 until mid-1983.

The engine that superseded the Type 4 engine in late 1983 retained Volkswagen Type 1 architecture, yet featured water-cooled cylinder heads and cylinder jackets. The wasserboxer, Volkswagen terminology for a water-cooled, opposed-cylinder (flat or 'boxer engine') was subsequently discontinued in 1992 with the introduction of the Eurovan.

The Type 4 engine was also used on the Volkswagen version of the Porsche 914. Volkswagen versions originally came with an 80 horsepower (60 kW) fuel-injected 1.7-litre flat-4 engine based on the Volkswagen air-cooled engine. In Europe, the four-cylinder cars were sold as Volkswagen-Porsches, at Volkswagen dealerships.

Porsche discontinued the 914/6 variant in 1972 after production of 3,351 units; its place in the lineup was filled by a variant powered by a new 95 metric horsepower (70 kW; 94 bhp) 2.0-litre fuel-injected version of Volkswagen's Type 4 engine in 1973. For 1974, the 1.7-litre engine was replaced by a 76 metric horsepower (56 kW; 75 bhp) 1.8-litre, and the new Bosch L-Jetronic fuel injection system was added to American units to help with emissions control. 914 production ended in 1976. The 2.0-litre engine continued to be used in the Porsche 912E, which provided an entry-level model until the Porsche 924 was introduced.

For the Volkswagen Type 2, 1972's most prominent change was a bigger engine compartment to fit the larger 1.7- to 2.0-litre engines from the Volkswagen Type 4, and a redesigned rear end which eliminated the removable rear apron. The air inlets were also enlarged to accommodate the increased cooling air needs of the larger engines.

This all-new, larger engine is commonly called the Type 4 engine as opposed to the previous Type 1 engine first introduced in the Type 1 Beetle. This engine was called "Type 4" because it was originally designed for the Type 4 (411 and 412) automobiles. There is no "Type 2 engine" or "Type 3 engine", because those vehicles did not feature new engine designs when introduced. They used the "Type 1" engine from the Beetle with minor modifications such as rear mount provisions and different cooling shroud arrangements, although the Type 3 did introduce fuel injection on the "Type 1" engine.

In the Type 2, the Volkswagen Type 4 engine was an option from 1972. This engine was standard in models destined for the US and Canada. Only with the Type 4 engine did an automatic transmission become available for the first time in 1973. Both engines displaced 1.7 litres, rated at 66 metric horsepower (49 kW; 65 bhp) with the manual transmission, and 62 metric horsepower (46 kW; 61 bhp) with the automatic. The Type 4 engine was enlarged to 1.8 litres and 68 metric horsepower (50 kW; 67 bhp) in 1974, and again to 2.0 litres and 70 metric horsepower (51 kW; 69 bhp) in 1976. As with all Transporter engines, the focus in development was not on motive power, but on low-end torque. The Type 4 engines were considerably more robust and durable than the Type 1 engines, particularly in Transporter service.

Other applications

During the 1970s, in Brazil, Volkswagen made available the 1700 cc engine for its regular production car SP-2. The 1700 cc engine was identical to the 1600 cc version, but with enlarged cylinder bores.

Up until 2001, Beetle engines were also used to run several of the ski lifts at the Thredbo ski resort in New South Wales, Australia, and were maintained to a high standard by Volkswagen mechanics.

Also in Australia, in remote opal mines, Volkswagen engines were modified to air compressors for jack hammers, etc. They used two cylinders on one side as a motor, and modified the head on the other side to produce a flow of compressed air. The opal fields are very dry and hot, so an air-cooled compressor has an advantage over liquid-cooled. Beginning in 1987, Dunn-Right Incorporated of Anderson, South Carolina has made a kit to perform the conversion to compressor.[5]


Volkswagen AG has officially offered these air-cooled boxer engines for use in industrial applications since 1950, lately under its Volkswagen Industrial Motor brand. Available in 18 kilowatts (24 PS; 24 bhp), 22 kilowatts (30 PS; 30 bhp), 25 kilowatts (34 PS; 34 bhp), 31 kilowatts (42 PS; 42 bhp), 33 kilowatts (45 PS; 44 bhp) and 46 kilowatts (63 PS; 62 bhp) outputs, from displacements of 1.2 litres (73 cu in) to 1.8 litres (110 cu in), these Industrial air-cooled engines were officially discontinued in 1991.


The air-cooled opposed four-cylinder Beetle engines have been used for other purposes as well. Limbach Flugmotoren has since 1970 produced more than 6000 certified aircraft engines based on the Beetle engine.[6][7][8][9] Sauer has since 1987 produced certified engines for small airplanes and motorgliders,[10] and is now also producing engines for the ultralight community in Europe.[11][12]

Especially interesting is its use as an experimental aircraft engine. This type of VW engine deployment started separately in Europe and in the US. In Europe this started in France straight after the Second World War using the engine in the Volkswagen Kübelwagen that were abandoned in the thousands in the country side[13] and peaked with the JPX engine.[14] In the US this started in the 1960s when VW Beetle started to show up there.[13] A number of companies still produce aero engines that are Volkswagen Beetle engine derivatives: Limbach, Sauer, Hapi, Revmaster, Great Plains, Hummel, the AeroConversions AeroVee Engine, and others. Kit planes or plans built experimental aircraft were specifically designed to utilize these engines. The VW air-cooled engine does not require an expensive and often complex gear reduction unit to utilize a propeller at efficient cruise RPM. With its relative low cost and parts availability, many experimental aircraft are designed around the VW engines.[15][16]

Formula V Air Racing uses aircraft designed to get maximum performance out of a VW powered aircraft resulting in race speeds above 160 mph.[17]

Some aircraft that use the VW engine are:

Volkswagen air-cooled engine installed in an Evans VP-1 Volksplane

Half VW

1/2 Volkswagen engine mounted in a Hummel Bird.

For aircraft use a number of experimenters seeking a small two-cylinder four-stroke engine began cutting Type 1 VW engine blocks in half, creating a two-cylinder, horizontally opposed engine. The resulting engine produces 30 to 38 hp (22 to 28 kW). Plans and kits have been made available for these conversions.[18][19]

One such conversion is the Carr Twin, designed by Dave Carr, introduced in January, 1975, in the Experimental Aircraft Association's Sport Aviation magazine. The design won the John Livingston Award for its outstanding contribution to low cost flying and also was awarded the Stan Dzik Memorial Award for outstanding design.[19]

Other examples include the Total Engine Concepts MM CB-40 and Better Half VW.

Some aircraft that use the Half VW engine are:


  1. 1 2 3 Die Betriebsanleitung für den Volkswagen-Industriemotor Typ 122, Typ 126A. Volkswagen AG. Wolfsburg. March 1985. Page 29
  2. 1 2 3 Änderungen nach August 1965. Nachtrag zur Betriebsanleitung des Industriemotors. August 1966
  3. "Der Käfer – Eine Dokumentation Band 2" by A. Etzold, published by Motorbuch, Stuttgart in 1985 ISBN 3-7168-1613-2
  4. "Das große Buch der Volkswagen-Typen" by Lothar Boschen, published by Motorbuch, Stuttgart in 1983 ISBN 3-87943-799-8
  5. "Dunn-Right Incorporated". Dunn-Right Incorporated. n.d. Retrieved 16 January 2010.
  6. , Limbach L2400
  7. , Limbach L2000
  8. , Limbach L1700
  9. Limbach, Limbach Aero Engines
  10. Carat motorglider, Carat motorglider.
  11. Sauer Flugmotorenbau, Sauer Flugmotorenbau.
  12. Sauer in Groppo, Sauer in Groppo.
  13. 1 2 EAA Webinar John Monnett, John Monnett.
  14. JPX, JPX
  15. "In North Kitsap, Turning Old Cars Into New Planes". Kitsap Sun. November 29, 2009.
  16. Great Plans Aircraft Newsletter, Issue 3, 2010.
  17. Formula V Air Racing
  18. Millholland, L. E., and Graeme Gibson (November 2002). "The Better Half VW Engine – Engine Detail". Retrieved 26 May 2010.
  19. 1 2 Great Plains Aircraft Supply Co., Inc. (n.d.). "Type 1 - 1/2 VW Conversion Kit, Parts and Plans". Retrieved 14 May 2010.
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