Main Bearings, .040 Case, .010 Crank, .040 Thrust

OVERVIEW

When it comes to rebuilding a classic air-cooled Volkswagen engine, precision is the difference between a motor that lasts for decades and one that fails within the first few hundred miles. These EMPI Silverline Main Bearings are specifically engineered for engines where the magnesium or aluminum crankcase has seen significant wear and requires a substantial line bore. By utilizing a .040-inch oversize on the case diameter, a .010-inch undersize on the crankshaft journals, and a .040-inch oversize on the thrust surface, these bearings allow engine builders to rescue vintage cases that might otherwise be destined for the scrap heap. Whether you are restoring a numbers-matching Beetle or building a rugged off-road machine, these steel-backed bearings provide the structural integrity and oil-retention properties necessary to maintain consistent oil pressure and crankshaft stability under high-heat conditions.

The Silverline brand has long been a staple in the VW community, known for producing high-quality, steel-backed components that handle the unique thermal expansion characteristics of the flat-four engine. These bearings are manufactured with a specialized alloy coating that offers excellent embeddability, allowing any microscopic debris to be trapped within the bearing surface rather than scoring the crankshaft. The .040 thrust cut is particularly vital for cases that have suffered from excessive "crank walk," a common issue in high-mileage Type 1 engines where the flywheel side of the case becomes hammered out. By choosing this specific oversized thrust set, you ensure that the end-play can be set back to factory specifications, protecting your main webs and ensuring smooth clutch engagement for years to come.

FITMENT

These main bearings are designed for 1200cc to 1600cc based air-cooled VW engines. Please verify your case and crank machining dimensions before ordering.

• Volkswagen Type 1: Beetle and Super Beetle 1961-1979
• Volkswagen Type 1: Karmann Ghia 1961-1974
• Volkswagen Type 2: Bus / Transporter 1961-1971 (1600cc engines)
• Volkswagen Type 3: Squareback, Fastback, Notchback 1962-1973
• Volkswagen Type 181: Thing 1973-1974
• Custom Applications: Dune Buggies, Sand Rails, and Trikes using VW 1600cc based cases.

SPECS

• Part Number: 111-198-483OS
• Manufacturer: Silverline (Distributed by EMPI)
• Case Bore Diameter: .040 inches (1.00mm) Oversize
• Crankshaft Journal Diameter: .010 inches (0.25mm) Undersize
• Thrust Surface Width: .040 inches (1.00mm) Oversize
• Material: Steel-backed with high-grade babbitt lining
• Quantity: Complete set for one engine (Main journals 1, 2, 3, and 4)
• Manufacturing Location: Mexico

PRO TIPS

1. Triple-Check Your Machinist''s Work

Never assume that your case or crankshaft matches the labels on the boxes without personal verification. Before beginning your assembly, use a high-quality micrometer to measure your crankshaft journals and a dial bore gauge to measure the line-bored case. Because this bearing set uses a .040 case, .010 crank, and .040 thrust configuration, it is a "specialty" size. If your machinist accidentally bored the case to .020 or .060, or if the thrust face wasn''t cut to exactly .040 over, you will experience oil pressure failure or catastrophic engine lock-up. Always perform a "dry fit" of the bearings in the case halves to ensure they seat fully and that the dowel pins align perfectly with the bearing holes.

2. Align the Oil Holes and Dowel Pins

One of the most common mistakes in VW engine assembly is the misalignment of the main bearing oil holes. When installing the bearings into the case, ensure that the oil supply holes in the bearing shells line up perfectly with the oil galleries in the case. Furthermore, you must ensure the dowel pins are fully seated and that the bearing "tang" or hole drops over the pin correctly. If the bearing is sitting on top of the pin rather than over it, the case halves will not torque down evenly, which can distort the bearing shell and lead to immediate engine failure upon startup. Use a small amount of assembly lube to hold the bearing in place, but do not use so much that it masks a poor fit.

3. Managing the .040 Thrust Surface

The .040 thrust oversize is specifically designed to fix cases where the thrust wall (the area behind the #1 bearing nearest the flywheel) has been worn down. When using these bearings, your machinist must have specifically cut the thrust face of the case to accommodate the wider bearing flange. If you try to force a .040 thrust bearing into a standard or .020 cut case, the bearing will not seat, and you will be unable to close the case halves. Once the case is torqued, always check your crankshaft end-play using a dial indicator. Your target is typically between .003 and .005 inches. If your end-play is too tight, you cannot simply "wear it in"; you must identify the interference and correct it before final assembly.