Main Bearings, .020 Case, .030 Crank, .080 Thrust

OVERVIEW

When you are deep into a performance engine build or restoring a classic air-cooled powerplant, precision is the difference between a motor that lasts decades and one that fails in the driveway. These premium main bearings are specifically engineered for Volkswagen Type 1, 2, and 3 engines where both the engine case and the crankshaft require significant machining to return to a reliable state. This particular set is designed for a case that has been line-bored .020 inches (0.50mm) over and a crankshaft that has been ground .030 inches (0.75mm) under. Additionally, it features a specialized .080 inch (2.0mm) oversized thrust flange, which is essential for cases that have suffered heavy wear on the thrust surface behind the number one bearing. By utilizing these high-tolerance components from Appletree Auto, you are ensuring that your oil pressure remains stable and your internal clearances are exactly where the factory intended, even after decades of heat cycles and hard miles.

We understand that sourcing the correct bearing for a machined case can be a daunting task, but these units simplify the process by providing a perfect fit for heavily serviced components. Manufactured with a high-strength steel backing and a durable bearing alloy lining, these bearings offer superior embeddability and heat dissipation. The .080 thrust cut is a lifesaver for rare or vintage engine cases that would otherwise be destined for the scrap pile due to excessive crankshaft end-play wear. Whether you are building a high-revving street sleeper or a reliable daily driver Beetle, these bearings provide the structural integrity required to support the rotating assembly under load. Trust in the quality that professional engine builders rely on to keep the air-cooled legacy alive and running smooth.

FITMENT

These main bearings are designed for the Volkswagen Type 1 based engine platform. Please verify your machining measurements before ordering.

• Volkswagen Beetle: 1954 through 1979 (1200cc, 1300cc, 1500cc, and 1600cc based engines).
• Volkswagen Karmann Ghia: 1956 through 1974.
• Volkswagen Bus / Transporter: 1950 through 1971 (Up to 1600cc Type 1 style engines).
• Volkswagen Type 3 (Squareback, Fastback, Notchback): 1962 through 1973.
• Volkswagen Thing (Type 181): 1973 through 1974.
• Custom Applications: Dune buggies, sand rails, and trikes utilizing Type 1 VW engine cases.

SPECS

Detailed technical specifications for precise engine assembly:

• Case Bore Diameter: .020 inches (0.50mm) Oversize.
• Crankshaft Journal Diameter: .030 inches (0.75mm) Undersize.
• Thrust Surface Width: .080 inches (2.0mm) Oversize Flange.
• Bearing Material: Premium steel-backed alloy with high-fatigue resistance.
• Oil Hole Configuration: Pre-drilled for standard Type 1 oiling circuits.
• Part Number Reference: 111-198-477OS+2.
• Application: Type 1, 2, and 3 air-cooled VW engines.

PRO TIPS

1. Triple-Check Your Measurements

Before you even open the package, you must verify your machine shop''s work with a high-quality micrometer and a dial bore gauge. In the world of air-cooled VWs, it is common for cases to be bored to various stages. Ensure your case bore measures exactly .020 over standard and your crank journals are exactly .030 under. Using the wrong bearing size, even by a few thousandths of an inch, will result in immediate engine seizure or a total loss of oil pressure. Don''t guess; measure twice so you only have to build it once.

2. Align the Oil Holes and Dowel Pins

During installation, it is critical to ensure that the oil holes in the bearings align perfectly with the oil galleries in the engine case. Furthermore, pay close attention to the dowel pin holes. The pins must seat fully into the bearing shells without binding. If the bearing isn''t perfectly seated over the dowel pin, the case halves will not torque down correctly, leading to a warped bearing and catastrophic crank failure. We recommend a light coat of assembly lube on the bearing faces, but keep the backs of the bearings (where they meet the case) clean and dry to ensure proper heat transfer.

3. Managing the .080 Thrust Surface

Since this set features a .080 oversized thrust flange, your engine case must have been specifically machined on the thrust face to accommodate this extra width. After the crank is installed and the case is torqued to spec, you must check your crankshaft end-play using a dial indicator. Even with an oversized thrust bearing, you may still need to use shim packs behind the flywheel to achieve the factory-recommended end-play of .003 to .005 inches. Failure to set the end-play correctly can cause the thrust bearing to overheat and gall, potentially ruining your engine case and crankshaft.