Using a seven-step quality improvement process, some of the engine build-up factors adversely influencing the severity and precision of the Sequence VI dynamometer test were examined. Insights from engineering (theory) and database (statistical) analyses enabled a 23 factorial experiment to identify oil ring tension, piston ring side clearance, and piston fit as critical parameters in a 3-oil, 9-engine, 28-test program. High ring tension was shown to emphasize the friction reducing capability of higher performing oils and the deficiency of a lower performing oil. Interactions were noted. A helpful correlation of test severity with the engine calibration indicators was shown.