In a message dated 10/15/2000 10:48:57 PM Eastern Daylight Time,
ccrobins@ktc.com writes:
<< The reason to stay with the same grade bolt as was originally supplied
is that it's the only way to make the mfr's torque figures apply.
Torque figured are meant to stretch the fastener to the middle of its
tensile strength. Change the elasticity of the fastener and you change
the torque spec. Then you don't know what the correct figure is for the
application. >>
There are tables and charts that indicate the proper torque figures for the
different grade bolts. You just have to remember where you upgraded the
bolts. Also, upgrading would serve no purpose where strength was not an
issue, such as bolting the front part of the oil pan onto a 1500 engine--you
are threading into a small aluminum block, so even the torque figures have
to be different there than the rest of the pan. Using the same torque as
bolting into steel will strip out the aluminum threads. Don't ask me how I
know!! 8^)
--David C.
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