How you prepare a new engine for its first start up is critical to its life expectancy! Torco TBO Break-In Oil is a high-performance blend of hydro-processed petroleum base stocks and specially selected additives that prepare and protect vital engine parts during the first startup. It contains a high percentage of “Zinc” anti-wear chemistry for proper valve train and new cam break-in protection. The cleansing agents “scrub down” any contaminants left over from the build process and provides the proper film for new bearing protection. The Break-In Oil withstands viscosity break down and can also be used as a consistent monitor control oil or "reference oil" for engine studies using an engine dynamometer.