Volkswagen air cooled engine

The Volkswagen air cooled engine is one of the most widely used and versatile internal combustion engines in the world. Variations of this engine were produced by Volkswagen plants around the world from 1936 until 2006.

Cast iron cylinders, cast aluminium alloy cylinder heads and pistons, magnesium crankcase, and forged steel crankshaft and connecting rods were hallmarks of the design.

Type 1: 1.1–1.6 litres
Like the Volkswagen Beetle, the first Volkswagen Transporters (bus) used the Volkswagen air cooled engine, a 1.1 litre, DIN-rated 24 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. This engine proved to be so uncharacteristically troublesome that Volkswagen recalled all 1959 Transporters and replaced the engines with an updated version. 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) was slightly larger and considerably heavier than its predecessor, and lost its distinctive split front windscreen - which gained it common nicknames of 'Breadloaf' and/or 'Bay-window', or 'Loaf' and/or 'Bay' for short. The engine was also slightly larger - at 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, notchback, 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 drastically changed to allow for a much lower engine profile. This resulted in increased area for cargo stowage with the so-called "Pancake" or "Suitcase" engine. This engine's displacement would later increase to 1.6 litres.

Originally a single- or dual-carburetted 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 one of the first mass production consumer cars with such a feature (the first was the Type 4 VW 411).

1100

 * 1945–1953 Volkswagen Beetle
 * 1950–1953 Volkswagen Type 2

1200
The 30 kilowatts (40 hp) 1.2 litre can be modified by the addition of a big bore kit, which allows bigger cylinders and pistons from the stock 77 millimetres (3.03 in) to 83 millimetres (3.27 in) while keeping the stock crankshaft, cam, head, etc. and providing to a 25% power output increase.

1300
Europe 1966–1995 dual port version of 1.3 litre 1966 only

1500
1967–1971
 * 1967–1971 Volkswagen Puma

1600
1972–on

In the US, the 1600 single port was used on the following models:
 * Single port
 * 1966–1970 Type 3
 * 1968–1970 Type 2
 * 1970 Beetle
 * 1970 Karmann Ghia

In the US, the 1600 dual port was used on the following models:
 * Dual port
 * 1971 Type 2
 * 1971–1979 Beetle
 * 1971–1974 Karmann Ghia
 * 1971–1989 Volkswagen 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'), did not enjoy the reputation for longevity that the original air-cooled design had forged. From the very start, the engine suffered cylinder-to-head sealing problems, mostly due to galvanic corrosion, often a result of slack maintenance schedules. Volkswagen discontinued the engine in 1992, upon 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. This "tainted" the car in the opinion of many automotive critics of that era, and a little of that attitude persists to this day.

Slow sales and rising costs prompted Porsche to discontinue the 914/6 variant in 1972 after producing 3,351 of them; 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.

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.

The T2c, so called since it got a slightly raised roof — by about 10 centimetres (3.9 in) — in the early 1990s, was built for the South American and Central American markets. The T2c was produced in Mexico until 1991* with the 1.6 litre air-cooled Type 1 engine, and from 1991 until 1996 with water-cooled engines from the Volkswagen Golf (a VW/Audi 1.4 litre). Since 1997, the T2c has been built in Brazil with air-cooled engines for the Brazilian market, and with water-cooled engines for the Mexican market, the latter easily identified by their large, black-coloured, front-mounted radiators.

Since production of the original Beetle was halted in late 2003, the T2 remained the only Volkswagen model with the traditional air-cooled, rear-mounted boxer engine when the Brazilian model shifted to water-cooled on 23 December 2005. Previously, the watercooled T2c was sold in Mexico between 1991-2002.

Half VW
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.

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.