Volkswagen air-cooled engine

Volkswagen E-motor
Overview
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
Combustion
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 Typ 122[1]
Overview
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
Combustion
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)
Output
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

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 litres) 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).

1000

• 1938-1942^[3][4] KdF-Wagen
• 1941-1942 Volkswagen Kübelwagen

1100

• 1942-1944 Volkswagen Schwimmwagen
• 1942-1945 Volkswagen Kübelwagen, Volkswagen KdF-Wagen
• 1945–1953 Volkswagen Beetle
• 1950–1953 Volkswagen Type 2

1200

The 1.2 l engine is called Typ 122 and has a displacement of 1192 cm³.^[1] As industrial engine, its rated power is 22,8 kW at 3000 min⁻¹ without a governor, the highest torque 81,4 N·m at 2000 min⁻¹. With a governor set to 8% accuracy, the rated power is 21,33 kW at 3000 min⁻¹, the highest torque is 69,63 N·m at 2000 min⁻¹.^[2] For other applications, the power and torque output may vary.

1300

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

1500

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

• 1967–1971 VW Puma

1600

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:

• 1966 Type 3
• 1968–1970 Type 2
• 1970 Beetle (US only)
• 1970 Karmann Ghia (US only)

Twin port

The 1600 dual port was used on the following models:

• 1967-1973 Type 3
• 1971 onwards Type 2 (only 1971 in USA – superseded by Type 4 engine)
• 1971–1979 Beetle
• 1971–1974 Karmann Ghia
• 1971–1989 VW Puma

Type 4: 1.7–2.0 litres

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", 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,

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.

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]

Industrial

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.

Aircraft

AeroConversions AeroVee Engine

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:

References