1/2 VW Engine Plans

Looking for an affordable, reliable way to mount a 4-stroke engine on your ultralight or light aircraft? Transform a full-case Volkswagen engine into a high-performance 1/2 VW engine using our comprehensive, easy-to-follow plans!

Our detailed guide walks you through converting a standard 4-cylinder VW engine to run on just the front two cylinders. The conversion process includes removing the rear cylinders, modifying the crankshaft and cam, and customizing the cylinder heads, along with all the steps needed to seal openings and ensure a leak-free engine.

What’s included:

  • Over 30 pages of clear, step-by-step written instructions

  • Additional pages of detailed figures and technical drawings

  • Full-scale templates for creating precise parts

  • Vibrant color photos to guide every stage of your conversion

  • Spiral-bound, high-quality glossy paper for durability and ease of use

Whether you’re a seasoned builder or tackling your first aircraft engine project, these plans give you everything you need to take your VW engine from stock to flight-ready. Start building your 1/2 VW engine today and experience the satisfaction of running your creation!

Keep in mind that our plans call for using the entire case as this is the easier method and in many ways the preferred method for conversion. They do NOT specify how to do the cut-case type conversation.

Why Build a 1/2 VW Engine? Here’s Why It’s a Smart Choice:

  • Affordable & Accessible Parts: Replacement parts are low-cost, widely available online, and often even locally.

  • Lightweight Design: No heavy reduction drives or complex exhaust systems needed. Most crankcases are magnesium, making them about 33% lighter than aluminum alternatives. A well-built engine typically weighs just 85–90 lbs.

  • Impressive Power: Depending on the components you choose, your engine can produce 28–37 horsepower. This is usually just right for ultralight or very light aircraft applications.

  • Simple Air-Oil Cooling: The cylinders are air-cooled, with most of the cooling handled by the oil, eliminating the need for a heavy or complicated liquid cooling system.

A 1/2 VW engine offers a perfect balance of reliability, simplicity, and performance for homebuilders looking to power their ultralight or light aircraft efficiently and economically.

 

Order your own set of 1/2 VW Plans
#111 1/2 VW Plans $30

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Below is a list of the content provided in our plans:

  • HISTORY OF PLANS
  • WORK AREA AND CONDITIONS
  • ENGINE SELECTION and OPERATING SPECS
  • IGNITION
  • REQUIRED SEALANTS AND LUBRICANTS
  • (REQUIRED) PARTS LIST
  • SUPPLIERS
  • TOOLS AND SERVICES NEEDED (OR HAVE ACCESS)
  • STEP 1 – DISASSEMBLE AND CLEAN ENGINE
  • STEP 2 – INSPECT THE CRANK CASE
  • STEP 3 – PAINTING THE ENGINE
  • STEP 4 – ALTERING THE CASE
  • STEP 5 – CUTTING AND ALTERING THE CYLINDER HEADS
  • STEP 6 – CUT AND ALTER THE ROCKER ARMS AND SHAFTS
  • STEP 7 – CRANKSHAFT CUTTING AND ALTERING
  • STEP 8 – MOUNTING A PROP HUB
  • STEP 9 – CUT THE CAMSHAFT
  • STEP 10 – CREATING THE EXHAUST PIPES
  • FINAL ASSEMBLY
  • STEP 11 – CRANKSHAFT ASSEMBLY
  • STEP 12 – CRANKCASE PREPARATION
  • STEP 13 – CLOSE UP THE CASE
  • STEP 14 – OIL PUMP AND OIL SCREEN INSTALLATION
  • STEP 15 – PROP HUB SEAL
  • STEP 16 – PISTONS AND CYLINDERS
  • STEP 17 – SET DECK HEIGHT FOR PROPER COMPRESSION
  • STEP 18 – DISTRIBUTOR
  • STEP 19 – CYLINDER HEADS
  • STEP 20 – CARBS & FUEL PUMP & EXHAUST
  • STEP 21 – CRANKCASE BREATHER
  • STEP 22 – INITIAL STARTUP

Here Jim Pfarr does an excellent job of showing how to do the static timing for the 1/2 VW engine.

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