Rod Bearing, .030 Under, forType 1 VW Kolbenschmidt

OVERVIEW

When you are deep into a performance rebuild or a classic restoration of an air-cooled Volkswagen engine, the internal components you choose determine the ultimate longevity and reliability of your machine. These Kolbenschmidt Rod Bearings, specifically sized at .030 under, represent the absolute gold standard in engine internals. Kolbenschmidt has been the original equipment manufacturer for Volkswagen for decades, and for good reason. These bearings are engineered to provide the exact oil clearances required to maintain consistent oil pressure under the high-heat conditions common to air-cooled Type 1 engines. Whether you are saving a vintage forged crankshaft that has seen better days or preparing a daily driver for another hundred thousand miles, these bearings offer the metallurgical integrity and precision machining that cheap alternatives simply cannot match.

Choosing a .030 under bearing set is a critical decision typically made after a professional machine shop has inspected and ground your crankshaft journals to remove scoring, heat spots, or taper. Because the crank has been reduced by 0.75mm (.030 inches), you need a bearing with a thicker wall to take up that space while still allowing for a precise film of oil to protect the rotating assembly. These Kolbenschmidt sets are manufactured with a high-strength steel backing and a specialized bimetal lining designed to embed small particles and resist surface fatigue. By installing a trusted name like Kolbenschmidt, you are ensuring that your connecting rods won''t suffer from premature wear or catastrophic failure during high-RPM operation or hot summer cruises. Don''t gamble your entire engine build on inferior "no-name" bearings when you can have the peace of mind that comes with genuine German-engineered quality.

FITMENT

• Volkswagen Beetle: 1950 through 1979 (All Type 1 engines from 1200cc to 1600cc)
• Volkswagen Karmann Ghia: 1956 through 1974
• Volkswagen Bus / Transporter: 1950 through 1971 (Type 2 with Type 1 style engines)
• Volkswagen Thing (Type 181): 1973 through 1974
• Volkswagen Type 3 (Squareback, Fastback, Notchback): 1962 through 1973
• Custom Applications: Dune Buggies, Sand Rails, and Trikes utilizing a VW Type 1 engine case and crankshaft

SPECS

• Brand: Kolbenschmidt (Genuine OEM Quality)
• Undersize Dimension: .030 inches (0.75mm)
• Engine Type: VW Type 1, 2, and 3 (Air-Cooled)
• Material: High-quality bimetal alloy with steel backing for maximum heat dissipation
• Set Count: Complete set of 8 bearing halves (Covers 4 connecting rods)
• Manufacturer Part Number: 113-105-719
• Compatibility: Designed for standard VW connecting rods with 22mm wrist pins
• Oil Holes: Precision-drilled for optimal lubrication to the journal surface

PRO TIPS

1. Verify Crankshaft Measurements Before Installation

Never assume your crankshaft grind is exactly what was requested without verifying it yourself. Before unpacking the bearings, use a high-quality micrometer to measure each rod journal at multiple points to check for roundness and taper. For a .030 under bearing, your journal should be ground specifically to the manufacturer''s specified diameter minus .030 inches. Once the bearings are installed in the rods and torqued to spec (without the crank), use a dial bore gauge to check your actual oil clearance. Ideally, you are looking for .001 to .002 inches of clearance. If it''s too tight, you risk "spun" bearings; if it''s too loose, you''ll suffer from low oil pressure when the engine gets hot.

2. Proper Cleaning and Tang Orientation

Cleanliness is the most important factor in a successful bottom-end build. Before snapping the bearings into the connecting rods, use a lint-free cloth and brake cleaner to ensure the rod bore and the back of the bearing shell are completely dry and free of any oil or debris. Any speck of dirt trapped behind the bearing can create a "high spot," leading to localized friction and failure. When installing, ensure the "tang" or "tab" on the bearing shell seats perfectly into the machined slot in the rod and rod cap. These tangs are designed to locate the bearing laterally; they do not prevent the bearing from spinningonly proper crush and torque do that.

3. Use High-Quality Assembly Lube and New Rod Nuts

Standard motor oil is not sufficient for the initial startup of a fresh rebuild because it can drain away while the engine sits on the stand. Always use a dedicated high-pressure assembly lube on the bearing faces before joining them to the crankshaft journals. Furthermore, air-cooled VW connecting rod nuts are often considered "one-time use" items by top builders because they are subject to extreme stress and stretching. We highly recommend using a fresh set of rod nuts and torquing them to exactly 25 ft-lbs (for 1300-1600cc engines). Once torqued, ensure the rod has the proper side-to-side "wiggle" or end play on the journal to confirm nothing is binding before you close up the case.