Quote:
Originally Posted by JFP in PA
That has been an internet argument for years. Running my own business, as well as building race cars and engines for various racing venues over several decades, I am super critical about two things when it comes to torque specs: accuracy and reproducability. From everything I have read, and what I have learned myself, sometimes at considerable expense, a lubricated fastener will both attain the correct clamping force, and that clamping force can be accurately be repeated as necessary. Now that thread lubrication can come in many forms: thread locker, anti seize, or simple lubricant; all will provide some level of lubrication during assembly, and not all will provide the same degree of lubrication, but all provide some level, which is the improtant point. In their white paper, ARP discussed at length about finding both erradic and lower clamping pressure than desired when threads were assembled dry and torqued to a given spec, and higher and vastly more consistent clamping pressure when the treads were lubricated and torqued to the same value.
Yes, I have read, and often laughed at, internet stories about people having their wheels fall off because they use anti seize on the lug threads. Anti seize on the lugs both prevent thread galling over time, and incorrectly torqueing the fasteners. I litterally have no idea how many cars we have running around with anti seize on the wheel lugs, but I can tell you that none ever came back because either the wheel fell off or was damaged by excessive torque. Same can be said about engines we either worked on or built for customers. I can tell you that I have seen brand new and very expensive engine cases that demonstrated unequal drag when simply threading in new bolts or studs with my fingers. This one of many reasons why we always "chase" every threaded opening in an engine case before assembly, and use a small dab of ARP thread lubricant when assembling. Consistency matters.
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This is what I love about forums (forii?) like this where people can share their experiences, albeit some more extensive than others. I can't speak for anti-seize on lug nuts, because I never used it and never will. And I may not have much experience on porsches, but I have some experience on Subarus. And on the only two occasions where I used assembly Lube on head bolt threads I had to redo each of them within a year. One was a personal vehicle and the other one was a friend's vehicle, and both times the head bolts came off extremely easily. Was it a coincidence? I don't think so. They either came loose or I over torqued them beyond their limit. They are torque to yield bolts where you turn them of total of 180° Beyond a specified torque. Whatever happened, I'm never going to use assembly Lube on the threads again. Chase them, of course, if they feel like they're binding, and make sure the threads are clean, but no more assembly Lube for me..
Threaded Mode
