The 1968 Vw Beetle Engine often presents a challenge when trying to determine its displacement and horsepower. Unlike later models, external markings don’t reliably indicate whether you have a 1500cc or 1600cc engine. Both engine types share similar external appearances regarding cylinder sleeves and pistons. The most accurate way to identify your 1968 VW Beetle engine displacement is by internal inspection.
Determining 1968 VW Beetle Engine Displacement
To definitively confirm the displacement, you’ll need to remove the cylinder head. This allows you to measure the piston diameter and stroke. Using these measurements, you can calculate the engine’s actual displacement using the following formula: Displacement = π/4 bore² stroke * number of cylinders.
Further measurements, such as combustion chamber volume and cylinder deck height, enable you to calculate the compression ratio. Knowing the displacement and compression ratio allows for estimating horsepower, particularly if the compression ratio remains stock.
Rebuilding a 1968 VW Beetle Engine: 1600cc Conversions
Decades ago, rebuilding a 1500cc engine with original parts was feasible. Today, finding new old stock (NOS) 1500cc piston and cylinder (P&C) sets is rare and expensive. Conversely, 1600cc P&C sets are more readily available and affordable. Furthermore, they are compatible with the 1500cc engine case without requiring machine work. Consequently, many 1500cc engines are upgraded to 1600cc during rebuilds due to parts availability and cost-effectiveness.
Identifying Key Features of the 1968 VW Beetle Engine Case
While displacement requires internal inspection, you can externally identify some key features of your 1968 VW Beetle engine case:
- Oil Pressure Relief Plug: Look for a single oil pressure relief plug on the bottom of the case. This indicates smaller oil passages and an oil pump with smaller gears, resulting in lower oil volume. Later dual-relief cases are generally preferred due to larger oil passages and improved oil pressure regulation.
- Case Embossing: Check the sides of the crankcase for embossing like “AS21” or “AS41,” designating the magnesium alloy used. This marking may also indicate the manufacturing location, often VW Germany.
Conclusion
Accurately identifying the displacement of a 1968 VW Beetle engine requires a more in-depth process than simply checking external markings. Internal measurements are crucial for definitive confirmation. However, external features like the oil pressure relief plug and case embossing offer valuable insights into the engine’s characteristics. Understanding these elements helps enthusiasts and mechanics make informed decisions about maintenance and potential upgrades for their classic VW Beetles.
