Engine Break-In Oil Additive Lucas TB Zinc-Plus Engine Break-In Oil Additive is designed for all who fear the initial break-in period of any new motor, especially if they are running a flat tappet camshaft. After reviewing our customer service requests, we found that many of our customers had requested an additive package that would protect the new or rebuilt hot rod or race motor they have built. The new Lucas Oil TB Zinc-Plus has an additive package that will help seat in the new rings while providing an excellent extreme pressure additive package that will help protect the entire valve train, and of course, the camshaft.