We present a study of the main bulk properties susceptibility, magnetization, resistivity, and specific heat of CePt3B1 amp; 8722;xSix, an alloying system that crystallizes in a noncentrosymmetric lattice, and derive the magnetic phase diagram. The materials at the end point of the alloying series have previously been studied, with CePt3B established as a material with two different magnetic phases at low temperatures antiferromagnetic below TN 7.8 K, weakly ferromagnetic below TC amp; 8776;5 K , while CePt3Si is a heavy fermion superconductor Tc 0.75 K coexisting with antiferromagnetism TN 2.2 K . From our experiments we conclude that the magnetic phase diagram is divided into two regions. In the region of low Si content up to x amp; 8764;0.7 the material properties resemble those of CePt3B. Upon increasing the Si concentration further the magnetic ground state continuously transforms into that of CePt3Si. In essence, we argue that CePt3B can be understood as a low pressure variant of CePt3Si