Driven Break In Engine Oil 10W-40 BR4010W 40 Driven Racing Oil BR break in motor oil is used to break in and dyno all engines. Petroleum oil provides the highest levels of zinc and phosphorus for flat tappet engines. Additive package promotes ring seal and provides maximum protection available for cams and lifters during initial break in. It requires no additional additives and is good for full power pulls on the dyno, one night of racing or up to 400 miles on the street. It provides