Engine valve and method for making the same

An internal combustion engine valve to be reciprocated in a valve guide in an engine, said valve comprising:

• a valve stem centered on an axis and comprising first and second parts,
• said first part comprising a tubular metal member having an outwardly flared first end portion and a second end portion, said tubular metal member having a chamber extending axially throughout said tubular metal member, said chamber comprising a flared chamber portion defined by said first end portion and a cylindrical chamber portion defined by said second portion, said chamber being open at said first end portion and at said second end portion, said tubular metal member being one piece of homogenous material,
• said second part comprising a metal piece coaxial with said tubular metal member, said metal piece having first and second ends, said first having a first weld connection to said second end portion of said tubular metal member, said metal piece having a second end spaced from said tubular metal member, said metal piece having a solid cross-section portion between said first and second ends, said metal piece having a continuous circumferential groove in said solid cross-section portion, said metal piece being one piece of homogenous material;
• and
• a metal cap centered on said axis and coaxial with said tubular metal member, said cap having a periphery and a second weld connection at said periphery to said outwardly flared first end portion of said tubular metal member, said cap closing said flared chamber portion at said flared first end portion and having an inner surface facing into said chamber, said metal cap being one piece of homogenous material;
• said tubular metal member and said metal piece being for location in the valve guide and having respective lengths enabling said first weld connection to always be in the valve guide.

A method of making an internal combustion engine valve to be reciprocated in a valve guide in an engine, said method comprising the steps of:

• making a first valve stem part of one piece of homogenous material and comprising a hollow metal member having an outwardly flared first end portion and a second end portion, said hollow metal member having a chamber extending axially throughout said member, said chamber comprising a flared chamber portion defined by said first end portion and a cylindrical chamber portion defined by said second end portion, said chamber being open at said first end portion;
• making a second valve stem part which is one piece of homogenous material and comprising a metal piece having first and second ends and having a solid cross-section portion between said first and second ends;
• making a continuous circumferential groove in said solid cross-section portion;
• welding said first end of said metal piece to said second end portion of said hollow metal member so that said metal piece and said hollow metal member are coaxial, said second end being spaced from said hollow metal member;
• making a metal cap of one piece of homogeneous material and having a periphery, an inner surface, and an outer surface, said inner surface being conical in shape and tapering axially away from said hollow metal member as said inner surface extends inward from said periphery, said cap having an outer surface which is conical in shape and tapering axially away from said hollow metal member as said outer surface extends inward from said periphery;
• and
• welding said periphery of said metal cap to said outwardly flared first end portion of said hollow metal member to close said flared chamber portion with said inner surface facing into said chamber.