| 摘要 |
A thin-walled valve guide insert for lining and relining a valve guide of an internal combustion engine includes opposing ends each having a tapered insertion section thereon. The tapered insertion section defines a reduced outer diameter to facilitate installing the insert into a valve guide bore have a nonchamfered opening, and further defines a reduced inner diameter so that the insert has a substantially continuous wall thickness throughout its length and thus maintains the structural integrity of the insert from end to end. In the preferred embodiment, the valve guide insert is made of a phosphor bronze material of about .018 inch thickness or less, and includes a lengthwise slit therein. The insert is sprung open longitudinally along the slit and must be radially compressed so that the insert defines a sufficiently small outer diameter so that it can be axially installed in a press-fit condition into the valve guide bore of the engine. Both ends of the insert are formed with the tapered insertion section so that the insert can be positioned without regard to which end is directed toward the valve guide. Also disclosed is a tool for inserting the insert into the guide valve, the tool including an outwardly tapered junction adapted to spread one of the tapered insertion sections of the insert into longitudinal alignment with the insert to reduce the tendency to crush same from end forces exerted on the insert while installing the insert into the valve guide. Still further a process is disclosed for forming the guide valve insert with ends having tapered insertion sections thereon.
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