Air-cooled Type 1 engine evolution explained

Unhindered by the need for water, Volkswagen’s Type 1 air-cooled engine was one of the principle reasons behind the lasting success of the Wolfsburg firm. Here’s a rundown of how it’s changed, along with a useful reference guide to engine numbers…

VW’s air-cooled engine was designed to be low revving, long-lasting and able to cope with all manner of owner abuse. And, of course, without water it could neither freeze or boil – an aspect that explains why so many Beetles still run their original powerplant!

While the basic Type 1 engine design barely changed, it’s gone through years of evolution over the decades, gaining more power, but also becoming more complex, especially when fuel emissions became important in the early ‘70s and fuel injection was added. That said, if lovingly looked after, with regular oil changes every 3000 miles, there’s no reason why an air-cooled lump can’t keep going, and going…

Here’s a summary of the most important changes, along with a list of engine codes to help you decipher what engine’s in your car; something that’s crucial when it comes to ordering parts!

The first 985cc flat-four engine produced just 23.5bhp at 3000rpm (below), allowing the early KdF-Wagen to scoot along at 95km/h. However, it wasn’t enough for the military Kubelwagens, so capacity grew to 1131cc and power to 25bhp in 1943. It was this engine that lasted in the Beetle until late 1953.

A new oil bath air filter and better cooling made the Type 1’s 1131cc engine more efficient, as did the use of a Solex 28PCI carburettor. Although capacity was increased again soon after to 1192cc by pushing the cylinder bore from 75mm to 77mm, resulting in an additional five more horses. Top speed in the Beetle went from 102km/h to 110km/h (68mph).

An all-new 1192cc engine with stronger crankcase, modified fuel pump drive and wedge-shaped combustion chambers, was introduced in August 1960 (for the ’61 model year), giving a power output of 34bhp at 3,600rpm. It is recognisable by its removable dynamo pedestal. The 1192cc engine lasted until the end of German production, though an alternator replaced the original dynamo in 1975.

The 1300 arrived (1285cc) which used the crank from the Type 3 1500 to lengthen its stroke, boasting a power output of 40bhp. As with all Type 1 engines built from July 1962, a new ‘fresh air’ heating system was used. At about this time, VW was developing engines for its new range of family saloons; namely the Type 3. While fundamentally the same, flatter profile cooling shrouds instead of the more traditional, Type 1 upright fan housing were the main distinguising features. However, the Type 4 from 1968 used an all-new engine – we blogged about it recently here.

The 1493cc engine (below) was made available in the Type 1, producing 44bhp at 4,000rpm. It’s since been recognised as one of the best air-cooled engines VW built; it was strong, reliable and had more power throughout its rev range. You can identify it by its twin air intakes on the oil bath air cleaner.

Making its debut this year in the Type 1 was the 1584cc engine with dual inlet ports in the cylinder heads. It produced a heady 50bhp at 4,000rpm – making it the most powerful VW offered to date.

To meet ever more stringent emission controls in the USA, VW fitted a Bosch AFC fuel-injection system on certain Type 1 models (as below), incorporating a catalytic converter to further clean up the exhaust gases.

Engine codes
It’s always interesting to know what engine’s in your vehicle and you can check by looking at the prefix. That well tell you the origins of the actual crankcase, but that might not necessarily give you an accurate picture of the engine in its entirety. The majority of engines may have been modified or had parts from a different era engine fitted. Engine number prefixes were first used in 1965 with the introduction of the 1300, with other air-cooled engine numbers as follows:

Type 1
1- = 25bhp (pre-Jan ’56)
2,3,4 = 1200cc 30bhp (1955-’65)
5,6,7,8,9 = 1200 34bhp (1961-’65)
D0, D1 = 1200 34bhp (for Mexican Beetles after ’77)
E0 = 1300 37bhp (1966-’70)
F0, F1, F2 = 1300 40bhp (1966-’70)
H0, H1 = 1500 44bhp (1967-’70)
H5 = 1500 (1968-’70)
L = 1500 40bhp (1967-’70)
AB = 1300 44bhp (1971-’73)
AC = 1300 40bhp (1971-’73)
ACD = 1600 46bhp (1992-2004, Mexican, fuel injected)
AD = 1600 50bhp
AE = 1600 48bhp (US, 1971)
AF = 1600 46bhp
AG = 1600 44bhp (Type 181)
AH = 1600 48bhp (1973-’74, US)
AJ = 1600 50bhp (1975-’79, US, fuel injected)
AK = 1600 48bhp (1973, US)
AL = 1600 48bhp (Type 181)
AM = 1600 48bhp (Type 181, US)
AR = 1300 44bhp (1974-’75)
AS = 1600 50bhp (1974-’79)


For reference, here’s the relevant engine codes for Volkswagen’s other air-cooled engines.

Type 2
20- = 25bhp (pre-Jan ’56)
2,3,4 = 1200 36bhp (1955-’60)
5,6,7,8,9 = 1200 40bhp (1961-’65)
O = 1500 (1963-’65)
H0 = 1500 (1966-’67)
L0 = 1500 (1967)
B0, B5 = 1600 (1968-’70)
C0 = 1600 44bhp (1968-’70)
AD = 1600 50bhp (1971-’73)
AB = 1300 44bhp (1971)
AE = 1600 50bhp (1971)
AS = 1600 50bhp (1974-’79)
CB = 1700 manual transmission (1972/3)
CD = 1700 auto (1973)
AW = 1800 twin carb, fuel injection (1973/4)
AP, ED = 1800 (1974/5)
GD, CJ, GE, CU, CV = 2000 (1976-’83)

Type 3
0 = 1500 (1961-’65)
K0 = 1500 54bhp (1866-’72)
M0 = 1500 52bhp (1966-‘72]
P0 = 1600 50bhp (1966/67)
T0 = 1600 (1966-’73)
U0 = 1600 (1968-’73)
U5 = 1600 (1971-’73)
X = 1600 (1972)

Type 4
V = 1700 68bhp (1969)
X = 1700 68bhp (1969/70)
W = 1700 80bhp (1971)
EA = 1700 (1971-’72)
EB = 1700 (1973, Californian fuel injected)
EC, AN, AT = 1800 (1974)

Type 25
CT = 1600 50bhp air-cooled unit used in T25
CU/CV = 2.0-litre, 70bhp air cooled unit used in T25




23 responses to: Air-cooled Type 1 engine evolution explained

  1. Hi, can anyone help please. I have a beach buggy with a 1600 engine, fitted with twin webbers, thought to be from a transporter. Serial number AS413043.101.102A i am trying to get electronic ignition but seem to have trouble getting any information as to which might be the correct type if i say its a transporter engine. Any help identifying which engine it comes from would be amazing. Thanks.

    1. You need the model number from the distributor to source an electronic ignition. The case number is irrelevant,as the distributor may not be original to the engine. My guess is that you have the immensely popular 009 distributor. Extremely easy to source an ignition from compufire.

    2. Try looking into Pertronix Ignitor. They may have one for your particular application (I.E. do your homework, check engine #s). They look relatively simple to install. Hopefully this will help.

  2. Hello I am trying to source a 985cc engine for the 1940s if possible in any condition, please contact me if you have one for sale.

  3. I bought two vw beetle engines and suspect one is a 1300 it has longer barrels but same size pistons.Is the crank 6th row a different size as both the cranks I’ve got have a 64mm throw ?

  4. Hi I was wondering if anyone here could help me identify the engine I have ina dune buggy I recently bought. The engine code is E882996. I was hoping to find out what year it is and what size it is. Thank you

  5. Great information. Thanks!
    I’ve been trying find out more information about the customised engine that came with my T2 Late Bay. I was told it is a Porsche 356c spec rebuild.
    Your Serial Number references have helped me identify its origins as being from the AS generation.
    More to discover i’m sure.

  6. Hi Guys,
    Trying to find out what year my 1600 VW engine is but no luck. Engine number starts with ME that most info advises is a inline 4 diesel , but this is defiantly a 1600 flat 4 petrol, any info would be very appreciated.
    Thanks in advance.

  7. I have a VW beetle 1975 model and need to restore it to full functionality. The challenge is getting spare parts for VW in Kenya.
    Can someone help on to get the parts for VW beetle.

  8. Hi everyone!
    I have a 1300 engine equipped with dual carburetor Solex 32. How can I configure these carburetors and engine to be more efficient and get more out of what the engine can offer?

  9. Hi,

    My engine is the same as that in the first picture, but I have no other info about it. My Beetle is a ’72 from the UK but has had an engine replacement at some stage. Can you tell me more about the engine in the first pic?


  10. Hi, I need to change the crankcase on by 1300 air cooled engine (AB code). Are all the beetle engine crankcase’s the same or do I specifically need to look for a 1300 one? Will be moving the crankshaft, heads, pistons etc from the old one.
    Does anyone know how to repair the crankcase if its damaged by the engine oil strainer at the bottom? Thx

  11. I have a sand rail with a VW 1600cc engine AK138858. just wondering if anyone has any info. Wanting to change plugs, distributor and oil. Any info will help greatly. Thanks

  12. I’m cleaning out my house which used to be my father’s, he was into VW bugs, and I came across a VW engine block. I noticed the generator mount is part of the casting, not a separate piece. the numbers on the pad below the generator mount are “1534490”. the numbers on the lower part of the castings ( of the engine casings ) are ” 111 101 102A ” and ” 111 101 101A “. there is a distributor and fuel pump on the engine. I know there is A LOT of ” old school ” VW people out there, and would like to find a home for this find. please contact me if you or anyone you know is interested.

Leave a Reply

Your email address will not be published. Required fields are marked *