How Does Oil Flow in a Small Block Chevy?

by Warren Davies

A good lubrication system is essential to the longevity of engine components. A full-pressure lubrication system sends oil to all the engine surfaces that have contact with each other.


A Chevy engine employs a wet-sump system. A supply of oil is stored underneath the crankshaft. Passages link this supply through the cylinder block and heads, and to the crankshaft itself.

Oil Pump

An oil pump sends the oil through a filter, onto a 1/2-inch gallery just above the camshaft. The oil is sent to the pump continuously through a 1/2-inch pump inlet.

Cam Bearings

The oil is sent through a groove near the rear cam bearing; it lubes the lifters and rear main bearings. The front cam bearings have grooves, which take the lube to the front main bearings.


The oil passes through passages in the upper main bearings. It then moves through the crankshaft main journals to the rod journals.

Cylinders and Valve Stems

The crankshaft spins, and oil is thrown into the cylinders. Oil travels through the pushrods and over the rocker arms, lubing the valve stems.

About the Author

Warren Davies has been writing since 2007, focusing on bespoke projects for online clients such as PsyT and The Institute of Coaching. This has been alongside work in research, web design and blogging. A Linux user and gamer, warren trains in martial arts as a hobby. He has a Bachelor of Science and Master of Science in psychology, and further qualifications in statistics and business studies.

Photo Credits

  • photo_camera restored classic chevy belair grill image by Jorge Moro from