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

OVERVIEW

When you are deep into a performance engine build or resurrecting a classic magnesium engine case that has seen decades of service, precision is the only language that matters. These IAP Main Bearings are engineered specifically for those specialized situations where both the engine case and the crankshaft have undergone significant machining to restore structural integrity and roundness. In the world of air-cooled Volkswagens, a case that has been bored .080 over and a crankshaft turned .020 under requires a bearing that bridges that gap with absolute metallurgical perfection. This set is designed to provide a rock-solid foundation for your rotating assembly, ensuring that oil clearances are maintained to factory-plus specifications even after the heavy machining required to save a vintage block.

The importance of the .080 thrust cut cannot be overstated for builders working with high-mileage cases. Over time, the constant fore-and-aft movement of the crankshaft can pound out the thrust surface of the engine case, leading to excessive end-play and potential catastrophic failure. By machining the case thrust surface .080 inches and utilizing these oversized thrust bearings, you effectively "reset" the engine''s life cycle, providing a fresh, flat surface for the crankshaft to ride against. These bearings are manufactured from high-grade alloy materials designed to withstand the thermal expansion cycles unique to the air-cooled environment, ensuring that your Beetle, Karmann Ghia, or Bus stays on the road with consistent oil pressure and minimal friction for years to come.

FITMENT

This bearing set is designed for Type 1, 2, and 3 air-cooled Volkswagen engines that have been machined to the specific dimensions of .080 case, .020 crank, and .080 thrust. Compatible models include:

• Volkswagen Beetle: 1954-1977 (Standard and Super Beetle)
• Volkswagen Karmann Ghia: 1956-1974
• Volkswagen Bus / Type 2: 1954-1971 (Up to 1600cc Dual Port)
• Volkswagen Type 3: 1961-1973 (Squareback, Fastback, Notchback)
• Volkswagen Thing: 1973-1974
• Custom Applications: Dune Buggies, Sand Rails, and Trikes utilizing Type 1 based engine cases.

SPECS

• Manufacturer: IAP (International Auto Parts)
• Part Number: 111-198-49580
• Case Bore Size (Oversize): .080 inches (2.00mm)
• Crankshaft Journal Size (Undersize): .020 inches (0.50mm)
• Thrust Surface Size (Oversize): .080 inches (2.00mm)
• Material: High-Performance Bearing Alloy
• Engine Type: VW Type 1, 2, 3 (1200cc, 1300cc, 1500cc, 1600cc based)
• Components Included: Full set of main bearings for one engine.

PRO TIPS

1. Triple-Verify Your Machining Dimensions

Before you even crack open the assembly lube, you must verify the work done by the machine shop. Use a high-quality micrometer to measure your crankshaft journals and a dial bore gauge to measure the engine case bore with the case halves torqued to specification (without bearings). This ensures that your "Double-Eighty" case and "Twenty-Under" crank actually match the tolerances required for these bearings. Relying solely on the machine shop''s word without personal verification is a recipe for a "short-lived" engine build. Remember, in the air-cooled world, clearances are everything.

2. Proper Thrust Bearing Seating and Pin Alignment

When installing the thrust bearing (the one with the large flanges), pay extra attention to the dowel pin alignment. It is incredibly easy to accidentally "crush" a dowel pin or slightly cock the bearing if it is not perfectly seated. Apply a small amount of assembly lube to the bearing saddle, but keep the back of the bearing dry to ensure it "bites" into the case properly. Once the crank is laid in, rotate it by hand several times to ensure there is no binding. If you feel any resistance, stop immediately and check the alignment of the thrust bearing and the dowel pins.

3. Cleanliness is Next to Godliness

Because these bearings are designed for cases that have undergone significant machining (.080 is a heavy cut), there is a high probability that metal shavings or "swarf" may still be hiding in the oil galleys. You must use a set of oil galley brushes and high-pressure air to scrub the case multiple times. Even the smallest piece of leftover magnesium or aluminum from the boring process can get trapped behind these new bearings, causing a "high spot" that will lead to premature bearing wear or a spun bearing. Don''t trust that the case is clean just because it looks shiny; scrub those galleys until the white lint-free rags come out spotless.