Abstract: Tooling and process for installing a split type, circular snap ring into a slotted or grooved wrist pin journal of a piston utilizing an installation sleeve member with an internal bore therethrough which is positioned against the piston so that its bore is aligned with the piston's wrist pin journal. The bore in the installation sleeve including a tapered passage to progressively radially inwardly constrict the snap ring as it moves axially through the installation sleeve. An elongated plunger assembly is moved axially to engage the snap ring and move it through the bore of the installation sleeve. The plunger assembly is sized to permit it to move through the entire extent of the tapered portion and into the piston's journal so that in turn the snap ring is moved into the wrist pin journal and finally into alignment with a retainer slot or groove into which the snap ring can radially expand outwardly into a seated position.

Abstract: A tubular piston pin for an internal combustion engine being of lightweight and high strength design with a cylindrical exterior surface and a double hourglass shaped aperture defined by thin-walled end portions; a thin-walled intermediate portion and two thicker-walled portions therebetween. A method for easy and inexpensive piston pin manufacture includes: the formation of half pins by molding a metal slug between two dies each having tapered end portions, punching out a midportion or intermediate web or wall to form an aperture therethrough with a generally hourglass shape, and aligning and joining two half pins axially together to form a piston pin with the double hourglass shaped interior aperture.

Abstract: A tubular piston pin for an internal combustion engine being of lightweight and high strength design with a cylindrical exterior surface and a double hourglass shaped aperture defined by thin-walled end portions; a thin-walled intermediate portion and two thicker-walled portions therebetween. A method for easy and inexpensive piston pin manufacture includes: the formation of half pins by molding a metal slug between two dies each having tapered end portions, punching out a midportion or intermediate web or wall to form an aperture therethrough with a generally hourglass shape, and aligning and joining two half pins axially together to form a piston pin with the double hourglass shaped interior aperture.