The head bolt torque issue is like this-
Torque the bolts to some value. That torque value relies on the friction between the bolt head and the portion of the head where it seats. In general, the running torque (bolt thread on block thread) is minimal and not part of the calculation.
Once that torque is reached, there is an additional force required in order to make up for the thermal expansion and contraction that the engine will experience during operation. This force is measured by the amount that the bolt is turned in addition to the torque measured in the first instance. THAT is measured in degrees, as the bolts have been designed to stretch a certain amount with the additional turning, which cannot be determined simply with a torque wrench. Thus, that tool with the number of degrees indicated.
Torque is measured in units of force X length. i.e., pound-feet, ounce-inch, newton-meter. The torque on a threaded fastener provides a clamping force that is measured in pounds, ounces, or Newtons. It's easy to mix up the units of force and length, and it happens all the time.
Contrary to what has been posited above, torque wrenches have been used for many decades prior to the introduction of disc brakes. Torquing a fastener to the proper value is necessary for all fasteners. It makes certain that the clamping forces necessary for the equipment so fastened to operate properly and safely, without leaking or failing (falling off due to being too loose or breaking fasteners due to being over-tightened).
Torque the bolts to some value. That torque value relies on the friction between the bolt head and the portion of the head where it seats. In general, the running torque (bolt thread on block thread) is minimal and not part of the calculation.
Once that torque is reached, there is an additional force required in order to make up for the thermal expansion and contraction that the engine will experience during operation. This force is measured by the amount that the bolt is turned in addition to the torque measured in the first instance. THAT is measured in degrees, as the bolts have been designed to stretch a certain amount with the additional turning, which cannot be determined simply with a torque wrench. Thus, that tool with the number of degrees indicated.
Torque is measured in units of force X length. i.e., pound-feet, ounce-inch, newton-meter. The torque on a threaded fastener provides a clamping force that is measured in pounds, ounces, or Newtons. It's easy to mix up the units of force and length, and it happens all the time.
Contrary to what has been posited above, torque wrenches have been used for many decades prior to the introduction of disc brakes. Torquing a fastener to the proper value is necessary for all fasteners. It makes certain that the clamping forces necessary for the equipment so fastened to operate properly and safely, without leaking or failing (falling off due to being too loose or breaking fasteners due to being over-tightened).
If you get to thinking you’re a person of some influence, try ordering somebody else’s dog around.
