A variable turbine geometry (VTG) turbocharger , comprising: a turbine section having a turbine wheel and a plurality of guide vanes surrounding the turbine wheel , the plurality of guide vanes being configured to regulate a flow of exhaust gases to the turbine wheel by opening and closing; a compressor section ; a bearing section between the turbine section and the compressor section ; an actuation pivot shaft (APS) configured to mediate actuation of the opening and closing of the plurality of guide vanes , the APS having a shaft portion extending through the bearing section , and a head end penetrating the turbine section ; a bushing rotatably supporting the shaft portion of the APS with a clearance therebetween, the bushing having a first end and a second end , and a head at the first end with an outer diameter that is greater than an outer diameter of the bushing between the head and the second end ; and a face seal assembly configured to seal a leakage of the exhaust gases through the clearance between the bushing and the APS , the face seal assembly including: a cup spring circumscribing the shaft portion near the head end and forming a face seal with the first end of the bushing , the cup spring including a concave face and a convex face , a composite ring seal circumscribing the shaft portion adjacent to the cup spring and forming a face seal with the cup spring and a mating structure , wherein the concave face faces and engages the head , and wherein the convex face faces the composite ring seal , and a spring circumscribing the shaft portion and engaging the second end of the bushing , the cup spring and the spring being held in compression with a retaining structure . a turbine section having a turbine wheel and a plurality of guide vanes surrounding the turbine wheel , the plurality of guide vanes being configured to regulate a flow of exhaust gases to the turbine wheel by opening and closing; a compressor section ; a bearing section between the turbine section and the compressor section ; an actuation pivot shaft (APS) configured to mediate actuation of the opening and closing of the plurality of guide vanes , the APS having a shaft portion extending through the bearing section , and a head end penetrating the turbine section ; a bushing rotatably supporting the shaft portion of the APS with a clearance therebetween, the bushing having a first end and a second end , and a head at the first end with an outer diameter that is greater than an outer diameter of the bushing between the head and the second end ; and a face seal assembly configured to seal a leakage of the exhaust gases through the clearance between the bushing and the APS , the face seal assembly including: a cup spring circumscribing the shaft portion near the head end and forming a face seal with the first end of the bushing , the cup spring including a concave face and a convex face , a composite ring seal circumscribing the shaft portion adjacent to the cup spring and forming a face seal with the cup spring and a mating structure , wherein the concave face faces and engages the head , and wherein the convex face faces the composite ring seal , and a spring circumscribing the shaft portion and engaging the second end of the bushing , the cup spring and the spring being held in compression with a retaining structure . a cup spring circumscribing the shaft portion near the head end and forming a face seal with the first end of the bushing , the cup spring including a concave face and a convex face , a composite ring seal circumscribing the shaft portion adjacent to the cup spring and forming a face seal with the cup spring and a mating structure , wherein the concave face faces and engages the head , and wherein the convex face faces the composite ring seal , and a spring circumscribing the shaft portion and engaging the second end of the bushing , the cup spring and the spring being held in compression with a retaining structure . <EOS>