Posted by Gordon on Wednesday, July 15, 2009 at 04:56:53 :
In Reply to: Hot torgue vs cold torque of head bolts posted by Robert N. on Wednesday, July 15, 2009 at 02:06:23 :
Basically there shouldn't be any, as everything should expand at the same rate, but ...
Things like blocks and heads are cast, and expand the same amount in all directions for a given temperature.
Forged components, like head bolts and rod bolts, actually expand a little more longitudinally (in the direction of forging) so will tend to be at a slightly lower torque when heated.
So, torque your bolts cold, warm the engine up to operating temperture, and then re-torque the bolts to the same torque settings when warm, job done.
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