A valve stem seal assembly (40; 60), comprising: an elastomeric seal (42; 62); a metal retainer (46; 66) having an upper (47; 75) and a lower (53; 96) inward vertical surfaces, with a continuous metal stop (82; 84) formed therebetween; and a metal valve guide (48; 68) in an elastomeric-to-metal seal with the elastomeric seal (42; 62) on a first outward vertical surface (52; 76) of the metal valve guide (48; 68); wherein the lower inward vertical surface (53; 96) of the metal retainer (46; 66) is in contact with a second outward vertical surface (54; 96) of the metal valve guide (48; 68), and both the lower inward vertical surface (53; 96) of the metal retainer (46; 66) and the second outward vertical surface (54; 96) of the metal valve guide (48; 68) are below the stop (82; 84), the stop (82; 84) in a block contact with a shoulder (86; 88) on the metal valve guide (48; 68) to prevent over-installation of the elastomeric seal (42; 62) and metal retainer (46; 66), and the shoulder (86; 88) on the metal valve guide (46; 68) being above the lower portion of the metal retainer (46; 66); characterized in that further the metal valve guide (48; 68) has a third outward vertical surface (89; 91) inwardly separated between the first (52; 76) and second (54; 96) metal valve guide outward vertical surfaces, by first (81; 83) and second (85; 87) metal valve guide horizontal surfaces, the second metal valve guide outward vertical surface (54; 96) being below the third metal valve guide outward vertical surface (89; 91), the retainer stop (82; 84) extending down to, and the shoulder (86; 88) being at, the farthest radial extension of the second metal valve guide horizontal surface (85; 87). an elastomeric seal (42; 62); a metal retainer (46; 66) having an upper (47; 75) and a lower (53; 96) inward vertical surfaces, with a continuous metal stop (82; 84) formed therebetween; and a metal valve guide (48; 68) in an elastomeric-to-metal seal with the elastomeric seal (42; 62) on a first outward vertical surface (52; 76) of the metal valve guide (48; 68); wherein the lower inward vertical surface (53; 96) of the metal retainer (46; 66) is in contact with a second outward vertical surface (54; 96) of the metal valve guide (48; 68), and both the lower inward vertical surface (53; 96) of the metal retainer (46; 66) and the second outward vertical surface (54; 96) of the metal valve guide (48; 68) are below the stop (82; 84), the stop (82; 84) in a block contact with a shoulder (86; 88) on the metal valve guide (48; 68) to prevent over-installation of the elastomeric seal (42; 62) and metal retainer (46; 66), and the shoulder (86; 88) on the metal valve guide (46; 68) being above the lower portion of the metal retainer (46; 66); characterized in that further the metal valve guide (48; 68) has a third outward vertical surface (89; 91) inwardly separated between the first (52; 76) and second (54; 96) metal valve guide outward vertical surfaces, by first (81; 83) and second (85; 87) metal valve guide horizontal surfaces, the second metal valve guide outward vertical surface (54; 96) being below the third metal valve guide outward vertical surface (89; 91), the retainer stop (82; 84) extending down to, and the shoulder (86; 88) being at, the farthest radial extension of the second metal valve guide horizontal surface (85; 87).