Head gasket
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(→Head gasket re-torquing: Minor clean up) |
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===Head gasket re-torquing=== | ===Head gasket re-torquing=== | ||
| − | The purpose of re-torquing the cylinder head fasteners is to restore the proper stretch to the head bolts after the first heat cycle. | + | The purpose of re-torquing the cylinder head fasteners is to restore the proper stretch to the head bolts after the first heat cycle. The idea behind this is that the engine assembly will expand as the engine temperature increases, this expansion will increase the compressive load on the head gaskets, causing a seating effect (sometimes referred to as creep relaxation) in composite head gaskets. |
The seating of the gaskets and threads results in a commensurate relaxation of the fasteners when the engine cools. Re-torquing the fasteners restores the proper stretch to the fasteners which will insure proper cold sealing of the gaskets as well as proper combustion sealing under full load. | The seating of the gaskets and threads results in a commensurate relaxation of the fasteners when the engine cools. Re-torquing the fasteners restores the proper stretch to the fasteners which will insure proper cold sealing of the gaskets as well as proper combustion sealing under full load. | ||
| − | + | *One re-torque is all that is necessary (unless the manufacturers instructions indicate otherwise) | |
| − | + | *If your engine uses torque-to-yield head bolts (TTY), do not re-torque | |
| − | + | *If there's any doubt, ask the manufacturer for a recommendation | |
| − | + | ||
====The process for re-torquing is as follows:==== | ====The process for re-torquing is as follows:==== | ||
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