I’m having difficulty picturing this. Can you post a pic or two showing how this works?

 

Torque wrench
((O)==========o
pivot ________1ft away from pivot
_____________||
___________(Weight)


Torque in ft-lb is literally the force applied on the turning pivot when the weight in lbs is 1 ft away from the pivot.

If torque wrench is set at 25lbs, then hanging any amount 25lbs or more 1 foot down the handle should result in clicky clacky noises, torque wrench handle moves but head does not rotate because 25lbs has been met and surpassed.

 

Glad I seen this thread. Just remembered I need to take my torque wrenches that I keep at the house to work tomorrow. The work place has a company that comes to the shop that certifies the calibrations or tells you to trash the wrench.

 

I Always check with two or three different torque wrenches before commit tightness.
Likewise I always use at least three different compression testers before commit an engine (to a rebuild or worse, due to a reading)


It isn't enough to 'calibrate' a torque wrench and then assume its been properly/perfect calibrated... they can fail suddenly without warning or at different amounts of torque than you tested it with.


It depends on what I am doing, how careful we will need to be, and how far you go from specification by the book.
For example tighten header bolts? Feel one bolt with a couple torque wrenches then do the rest by hand using common sense is fine. The pattern (inside -> out) and gradual stepwise increase in torque matters more than the tightness.
Next example, If tightening LS Engine rocker arms you MUST use a torque wrench and do NOT get liberal with the hardware or exceed the service manual as it could tear out rocker threads.
Some bolts I go by the 'minimum' rule. For example intake manifold for LS engines, it doesn't take much torque to fully seal the intake. I will install the intake with 'minimal' torque (perhaps less than service manual stated) and then test the intake (pressure test to 20psi of boost or whatever) to ensure it seals up. As bolts heat cycle and especially somewhere like the intake which is exposed to dirt/grime they tend to 'stick' (you have to "crack" them loose after a few months) so the issue of them becoming loose over time is insignificant compared to the consequences of overtightening or fatigue life cycle from hot/cold cycles with high tension (more tension on the bolt as it heat cycles is more likely to disturb the crystal lattice solid covalent bonds)

For some bolts on modern engines where the tension of the bolt being uniformly distributed and not to exceed some number (for example LS cylinder heads) is important, the factory provides one-time use bolts which stretch a predictable length after some torque is exceeded (yield style bolts) to help us make fewer mistakes.

The more' performance' based the engine and especially with forced induction, the more some or less specifications supplied by the factory will matter for some bolts, less for others, as the issue isn't always tightness, sometimes being super tight doesn't prevent a gasket from blowing out, an issue may relate with gasket flatness or surface preparation and bolt torque may be less important than tightening procedure itself.

 

Built many car and engines over the past 40 years. What the hell is a Torque wrench????