Roller-shoe mechanism is very often used in diesel high pressure pumps. The most encountered issues are caused by this mechanism components which are in direct contact. Lubrication, roughness, elements dimensions and profiles, coatings, working conditions can be adjusted so that the issues are reduced. Our paper aims to identify the most critical factors which influence the roller-shoe mechanism and to calculate the contact parameters during normal engine operation. The loads applied on the components are the key factors which contribute to all parameters calculation that ensure the contact optimization. The components clearance, friction coefficients, medium contact pressure, minimum lubricant film, equilibrium temperature are some of important parameters which are the basis of a correct functioning. Analysing the obtained results, it can be observed that the lubricant film thickness can be adjusted to establish a minimum safely drive shaft rotation. Considering these results new improvements methods will be analysed for roller-shoe contact development.