FASTENER ASSEMBLY

1 . A fastener assembly comprising:

a fastener including a head and a shank extending from the head, the shank having a necked portion;

a retainer including

an aperture through which the shank is inserted; and

at least one radially inwardly-projecting tang engaged with the necked portion of the shank to limit movement of the retainer along the shank to within the necked portion.

2 . The fastener assembly of claim 1 , wherein the shank includes a threaded portion, and wherein the necked portion is adjacent the threaded portion.

3 . The fastener assembly of claim 2 , wherein movement of the retainer along the shank in at least one direction is limited by the threaded portion.

4 . The fastener assembly of claim 1 , wherein the at least one radially inwardly-projecting tang includes a pair of opposed radially inwardly-projecting tangs engaged with the necked portion of the shank.

5 . The fastener assembly of claim 4 , wherein each of the opposed radially inwardly-projecting tangs includes an arcuate edge engaged with the necked portion of the shank, and wherein a ratio of the radius of the arcuate edge of each of the tangs to the radius of an inner periphery of the aperture is about 0.75:1.

6 . The fastener assembly of claim 4 , wherein each of the opposed radially inwardly-projecting tangs includes an arcuate edge engaged with the necked portion of the shank, wherein the outer diameter of the necked portion is greater than or substantially equal to twice a radius of the arcuate edges, and wherein the outer diameter of the necked portion is substantially equal to or less than twice a radius of an outer periphery of the aperture.

7 . The fastener assembly of claim 1 , wherein the retainer includes an upper surface defining a plane, and wherein the radially inwardly-projecting tang is obliquely oriented relative to the plane.

8 . The fastener assembly of claim 1 , wherein the retainer includes a circular outer periphery.

9 . The fastener assembly of claim 1 , wherein the at least one radially inwardly-projecting tang includes an arcuate edge engaged with the necked portion of the shank.

10 . A unitized engine component assembly comprising:

an engine component including an aperture and a lip projecting into the aperture;

a fastener including a head and a shank extending from the head, the shank having a necked portion;

a retainer positioned in the aperture of the engine component, the retainer including

an aperture through which the shank is inserted; and

at least one radially inwardly-projecting tang engaged with the necked portion of the shank to limit movement of the retainer along the shank to within the necked portion;

wherein engagement of the retainer and the lip substantially prevents removal of the shank from the engine component aperture.

11 . The unitized engine component assembly of claim 10 , wherein the shank includes a threaded portion, and wherein the necked portion is adjacent the threaded portion.

12 . The unitized engine component assembly of claim 11 , wherein movement of the retainer along the shank in at least one direction is limited by the threaded portion.

13 . The unitized engine component assembly of claim 10 , wherein the at least one radially inwardly-projecting tang includes a pair of opposed radially inwardly-projecting tangs engaged with the necked portion of the shank.

14 . The unitized engine component assembly of claim 13 , wherein each of the opposed radially inwardly-projecting tangs includes an arcuate edge engaged with the necked portion of the shank, and wherein a ratio of the radius of the arcuate edge of each of the tangs to the radius of an inner periphery of the aperture is about 0.75:1.

15 . The unitized engine component assembly of claim 13 , wherein each of the opposed radially inwardly-projecting tangs includes an arcuate edge engaged with the necked portion of the shank, wherein the outer diameter of the necked portion is greater than or substantially equal to twice a radius of the arcuate edges, and wherein the outer diameter of the necked portion is substantially equal to or less than twice a radius of an outer periphery of the aperture.

16 . The unitized engine component assembly of claim 10 , wherein the retainer includes an upper surface defining a plane, and wherein the radially inwardly-projecting tang is obliquely oriented relative to the plane.

17 . The unitized engine component assembly of claim 10 , wherein the retainer includes a circular outer periphery, and wherein the lip includes a circular inner periphery.

18 . The unitized engine component assembly of claim 10 , wherein the fastener is axially movable relative to the engine component between a first position, in which the retainer is engaged with the lip to prevent removal of the shank from the engine component aperture, and a second position, in which the head is engaged with the engine component.

19 . The unitized engine component assembly of claim 10 , wherein the engine component is a rocker arm pivot of an engine valve train.

20 . A method of unitizing a fastener and a component, the method comprising:

providing the component with an aperture and a lip projecting into the aperture;

providing the fastener with a shank and a necked portion on the shank;

inserting the shank through an aperture in a retainer;

deflecting a radially inwardly-projecting tang of the retainer upon inserting the shank through the retainer aperture;

engaging the necked portion of the shank with the radially inwardly-projecting tang;

inserting the retainer into the component aperture; and

resiliently deforming the retainer upon moving the retainer past the lip.

21 . The method of claim 19 , further comprising allowing the retainer to at least partially resume its undeformed shape after moving the retainer past the lip.