[Elarson]

One of the big aerospace OEM's that I do work for, has a super slippery proprietary thread lube that takes half the torque as engine oil to get the proper stretch. Torque is highly dependent on the thread lube, surface finish, steady turning method, etc. Stretch is independent of all those variables.

Eric

[mgarblik]

To add to what Eric posted. IMO, it is critical to follow the connecting rod manufacturers recommendations for what lube to use. Even though many connecting rod companies use ARP rod bolts, many do NOT use ARP Ultra Torque lube when designing their tightening specs. Many specify CMD Extreme Pressure lube #3. That is a popular one. Some specify engine oil only. Some do use Ultra Torque lube. As Eric mentioned, the torque value can vary wildly based on the lube used. One of the super nice features of the modern electronic torque wrenches with angle is the ability to see what the final torque reading is once a set angle has been reached. I tested several sets of Molnar rods which specify torque angle for tightening. I measured the stretch, angle and final torque. Angle and stretch matched really close. Final torque was not nearly as accurate. +-15% on average. That doesn't mean your connecting rods are going to fail, but definitely not as accurate.