Abstract: A valve stem seal can include an elastomeric component having a first portion for having a sealed engagement with a valve stem, a second portion for engaging a valve guide, and a pressure relief lip extending from the second portion. The first portion can be configured to extend away from or within the second portion, and the second portion can have a channel formed therein. The pressure relief lip can have a sealing configuration and a venting configuration. The venting configuration can allow excess exhaust gases to vent from a combustion chamber. After the venting of excess exhaust gases, the pressure relief lip can close to the sealing configuration to prevent oil from entering the combustion chamber.

Abstract: A valve stem seal can include an elastomeric component having a first portion for having a sealed engagement with a valve stem, a second portion for engaging a valve guide, and a pressure relief lip extending from the second portion. The first portion can be configured to extend away from or within the second portion, and the second portion can have a channel formed therein. The pressure relief lip can have a sealing configuration and a venting configuration. The venting configuration can allow excess exhaust gases to vent from a combustion chamber. After the venting of excess exhaust gases, the pressure relief lip can close to the sealing configuration to prevent oil from entering the combustion chamber.

Abstract: A two piece valve stem seal assembly including first and second generally cylindrical shells, one of which is partially axially nested or inserted within the other. The valve stem seal assembly also includes an engagement portion on the one of the shells for grippingly engaging the outer shell in order to substantially prevent or at least minimize the possibility of axial separation of the shells during subsequent assembly into an engine or other valve-containing device. The assembly may also optionally include a discontinuity on the one of the shells for axially retaining or axially interlocking the shells in order to substantially prevent or at least minimize such possibility of axial separation.

Abstract: A two piece valve stem seal assembly including first and second generally cylindrical shells, one of which is partially axially nested or inserted within the other. The valve stem seal assembly also includes an engagement portion on the one of the shells for grippingly engaging the outer shell in order to substantially prevent or at least minimize the possibility of axial separation of the shells during subsequent assembly into an engine or other valve-containing device. The assembly may also optionally include a discontinuity on the one of the shells for axially retaining or axially interlocking the shells in order to substantially prevent or at least minimize such possibility of axial separation.