By Mike Mavrigian
While traditional steel-backed babbit cam bearings perform well in most builds, when “radical” camshaft profiles, accompanied by extremely high valve spring pressures are featured, excess pressure is exerted against the camshaft lobes, which in turn pushes the cam journals against the bearings, leading to potential accelerated bearing wear, resulting in potentially decreased oil pressure. Also, while a “traditional” oiling system routes oil from the pump to the cam bearings, then to the main bearings and then to the rod bearings, in a competition block that features priority main oiling, the reverse occurs, with oil first being routed to the mains, and finally to the
cam bearings. With the use of high valve spring pressures, this potentially can result in decreased, or delayed lubrication to the cam bearings.
In order to address the needs of an extreme-performance engine, a viable alternative is the use of needle roller cam bearings, which provide increased stability and durability for extended high-RPM racing applications.
