Engine Camshaft Bearing

What Are Engine Camshaft Bearings?

Engine camshaft bearings are small but critically important components that support the camshaft and allow it to rotate freely within the engine block or cylinder head. Camshaft bearings are a type of journal bearing — cylindrical shells pressed into precision-machined bores — that provide a stationary surface for the camshaft journals to ride on. Their job sounds simple, but the engineering behind them is anything but.

The camshaft itself works in close synchronicity with the crankshaft to govern when your engine's intake and exhaust valves open and close. This precise timing directly controls combustion efficiency, power delivery, and exhaust expulsion. Without properly functioning camshaft bearings supporting that rotation, the entire valvetrain suffers.

Why Camshaft Bearings Matter

Camshaft bearings serve several vital functions simultaneously. They support the rotational motion of the camshaft at varying speeds, minimize friction by preventing metal-to-metal contact between the camshaft and engine block, and distribute the loads generated by valve train components — lifters, pushrods, and rocker arms — across the bearing surface. High-performance, turbocharged, and diesel engines face even greater bearing loads due to higher cylinder pressures and stiffer valve springs.

The bearings rely on hydrodynamic lubrication to do their job. As the camshaft spins, engine oil is drawn into the tight clearance between the journal and the bearing surface, forming a continuous pressurized film that completely separates the two metal surfaces. This oil wedge is what eliminates wear under normal operating conditions. If oil pressure drops, the wrong viscosity oil is used, or the bearings are installed with oil holes misaligned, that protective film collapses — and catastrophic wear follows quickly.

Signs of Worn Camshaft Bearings

• Knocking or ticking noises from within the engine compartment
• Unexplained drops in oil pressure — worn bearings allow oil to escape the bearing area faster than the pump can supply it
• Metal shavings in the oil — a sign of internal bearing material breakdown
• Decreased fuel efficiency due to increased friction and drag on rotating components

What to Know When Shopping for Camshaft Bearings

Camshaft bearings come in a variety of materials including babbitt (a softer lead-tin alloy prized for its embeddability), aluminum alloy, and copper-lead composites used in heavy-duty and high-performance applications. Material choice matters: softer babbitt-lined bearings can conform to minor bore misalignments during a rebuild, while harder materials offer greater fatigue strength under sustained high loads. Camshaft bearings are typically replaced as a complete set during any engine rebuild or overhaul — never just one at a time.

Proper installation is equally critical. The oil hole in each bearing must be carefully aligned — typically between the 2 and 3 o'clock position — to ensure the hydrodynamic oil wedge forms correctly. Even a slightly misclocked bearing can starve the camshaft of lubrication and cause failure within miles of startup. Always verify housing bore dimensions before installation, since block distortion from overheating can affect bearing fit and alignment.

Top Brands in Engine Camshaft Bearings

Federal Mogul is one of the most established names in OEM and aftermarket engine bearings. Through their Sealed Power and Speed-Pro product lines, Federal Mogul supplies camshaft bearings engineered to exacting tolerances, with bearing materials and alloys developed from decades of OEM partnership with major automakers. Their extensive catalog covers a broad range of domestic and import applications, making them a go-to choice for professional engine builders and serious DIYers alike.