Manifold Torque

[Cape Codder]

As to the use of torque wrenches spending 34 years working on military jets we used torque wrenches 1/4" drive up to 1" drive. Each wrench was turned back to zero (to take pressure off internal spring, so we were told) after each use and also calibrated every 180 days. I do have a 3/8" drive torque wrench of my own and always turn it back to zero after each use but don't know anywhere to have it calibrated. Point I'm trying to make is even if a torque wrench is used, with out the calibration as the Air Force did, do we still get the correct torque?

 

[TerryNJ]

My 3/8 drive torque wrench is the kind that you can't back off. My 1/2 drive gets backed off with each usage for the reasons you give. The difference in torque varies from bolt to bolt. It depends on the the fit and or the condition of the threads. Obviously, the tighter the fit of the threads, the more torque it will require to turn the nut and the less will be applied to the parts being tightened. It is possible to get similar torque readings on each nut, but the actual downward pressure on the nut may vary all over.
Terry

As to the use of torque wrenches spending 34 years working on military jets we used torque wrenches 1/4" drive up to 1" drive. Each wrench was turned back to zero (to take pressure off internal spring, so we were told) after each use and also calibrated every 180 days. I do have a 3/8" drive torque wrench of my own and always turn it back to zero after each use but don't know anywhere to have it calibrated. Point I'm trying to make is even if a torque wrench is used, with out the calibration as the Air Force did, do we still get the correct torque?

 

[JD 1931]

I just finished installing manifolds on my A and torqued them to 30 lbs in stages starting at 20 lbs. then start and let cool, I torqued the center ones first then the outside ones, after last torque let it cool down I checked them again. I used the 2 piece new copper set gaskets along with the new glands and every thing lined up.Thanks for the help I got here when I posted questions about manifold install...
J.D.