When I change the oil in my vehicle, I use “motor” oil. It says so right on the bottle. And what about motorcycles; it wouldn’t sound right calling them enginecycles. According to the definition, a motor is a type of engine, so I guess it really doesn’t matter.
For the sake of continuity in this book, a Volkswagen engine will always be called an engine and never a motor. Even though, personally, I enjoy calling them motors. It just rolls off the tongue better. ■
Engines
This publication covers the most-popular powerplant Volkswagen produced. These engines were installed in Type 1 Beetles, Karmann Ghias, Type 2 Buses (up to July 1971), Type 3 Squareback and Fastback, and the Type 181 Thing. Generally, every vehicle Volkswagen produced starting with the 1961 model year that used a Type 1–based engine will be covered within these pages.
Not only will this book cover the engines produced by Volkswagen but also the Type 1–based aftermarket engines. Did you know you can build a 100-percent brand-new air-cooled VW engine from aftermarket parts? This book will guide you with building those as well. With good rebuildable core engines becoming hard to find, this may be an option for you.
Type 1
In 1961, Volkswagen completely redesigned the Type 1 engine. Starting with a clean slate, very few components could be interchanged between the earlier 36-hp engine and the new 40-hp engine. Besides getting 4 hp more out of the same displacement (1,200 cc), many design elements were improved for ease of manufacturing and increased reliability.
For example, the fuel pump was relocated to the right of the distributor. The generator stand was separated from the engine case. The cam follower and pushrod became two separate components; they previously had a cumbersome one-piece design. The valves were angled in the cylinder heads, increasing flow. A spiral groove was cut in the backside of the crank pulley to return oil back to the crankcase during operation. These improvements were only slightly refined for the entire run of this design.
During the four years the 40-hp engine was available in the United States, Volkswagen produced more than 3.5 million vehicles worldwide. The US Type 1 VW market ended with the 1979 Beetle convertible, but this engine was produced by VW worldwide until 2003. It’s no wonder many of these engines are still around today.
Displacement and Horsepower Changes
In 1966, the United States was just at the beginning of what is known today as the muscle car era. Nearly every automobile manufacturer was caught up in the frenzy, including Volkswagen. The Type 1 engine got a whopping 25-percent increase in horsepower for 1966, growing from 40 to 50 hp!
The increase was due to many factors. The displacement was increased from 1,200 to 1,300 cc and was noted by a “1300” badge on the decklid. This was one of the few times Volkswagen ever bragged about engine size. The “1300” only lasted one year. The cylinder head was redesigned into what is known today as the single-port head.
Pre-1961 Engines and Practicality
Owners of earlier models with 25- and 36-hp engines might find this book useful, but those engines are not its main focus. These earlier engines have so little in common with the versions that are 40-hp and newer that it would be confusing to interject those differences within the context of building this more-popular version.
Parts are scarce for 25- and 36-hp engines and thus expensive for any pre-1961 VW engine. For this reason, it’s very common to swap the more powerful and less expensive engines from newer cars into these earlier models. A 40-hp engine is a direct bolt-in conversion for these earlier models. Unless the owner is a purist and is looking for a historically correct restoration, this is the route generally taken. ■
Engine Codes
This book will cover most versions of VW Type 1 engines after 1961 with the introduction of the 40 hp all the way through the fuel-injected 1,600-cc engines introduced in 1975. The following table provides the engine codes to identify a VW engine. ■
By 1967, automobiles were becoming faster and more refined every year. Manufacturers tried to outdo each other in order to sell more vehicles than the previous year. Volkswagen was no different, and the horsepower increased again. Displacement increased from 1,300 to 1,500 cc, netting a 3-hp gain, and the clutch diameter increased from 180 to 200 mm to handle the increased power. The charging system finally joined the rest of the industry by becoming 12 volts instead of 6 volts.
The single-port head had its final run in 1970, aided by an increase in displacement from 1,500 to 1,600 cc. The 1,600-cc single-port engine became the favorite for many years for its mixture of old-world simplicity with more power.
A key year in the development of VW’s engine program was 1971. This was the year the 1,600-cc dual-port engine was introduced. It produced a neck-snapping 60 hp! That’s 50-percent-more horsepower than the same basic design made 10 years prior. This version of the Type 1 engine remained relatively unchanged for the next three years. There were changes made to the charging system, replacing the generator with an alternator, adding a quieter muffler, and using different ignition timing that reduced the horsepower to 58 in 1973.
Beginning in 1975, all US Beetles and Super Beetles were fuel injected. They remained that way for the duration of their production. The Bosch L-Jetronic fuel injection reduced emissions enough to satisfy the US government while getting only slightly better fuel mileage. The horsepower numbers suffered in the balance, making only 50 hp.
Engine Identification
Identifying a Volkswagen engine is relatively easy. Along with the first letter or letters of the serial number, each engine provides clues to its pedigree with other factors. Knowing a few of these clues will come in handy when you are trying to decipher what you are looking at online or at a swap meet.
Maybe you are looking into purchasing a VW and you want to determine if it has the original engine. Spoiler alert! It probably doesn’t! A little knowledge can save a bunch of time determining exactly what engine you are looking at.
Intake Manifold
A seasoned professional can easily ballpark the VW engine version by looking at the intake manifold. There are only three basic intake manifolds for the carbureted Type 1 engine: Type 1 Beetles with 40-hp from 1961–1965, single-port 1966–1970, and dual-port 1971–1974.
The three different carbureted intake manifolds covered in this manual are: 40-hp 1961–1965 (left); 1,300–1,600 single-port head 1966–1970 (center); and 1,600 dual-port head 1971–1974 (right).
The easiest one to pick out is the dual-port manifold installed on 1,600-cc engines in 1971-and-newer engines. It has a three-piece design with a center section and aluminum castings that bolt to the heads. A dual-port manifold will always have a 1,600-cc engine. Remember that Volkswagen did make a 1,600-cc single-port engine; so if someone says it’s a 1,600, don’t assume it’s a dual-port engine.
If the engine has a three-piece intake manifold, it is a 1,600-cc engine. Volkswagen made a 1,600-cc single-port manifold in 1970, and it can be hard to distinguish this from a 1,300-cc (1966) or a 1,500-cc (1967–1969) just by looking at it. The serial number on the case of a 1,600-cc single-port will start with the letter B.
Single-port engines look very similar to the earlier 40-hp to the untrained eye. The intake manifolds look similar but aren’t the same. The easiest way to tell them apart is to look at where the manifold bolts to the head. The 40-hp