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c/aircraft-mechanics•the_janathe_jana•22d ago

Shoutout to the old timer who taught me to stop fighting torque specs

When I first started at Great Lakes Aviation back in 2017, I used to crank every bolt on a Cessna 172 right up to the max spec. I thought tighter was better. Then a 30 year vet watched me torque a camshaft bolt on a Lycoming and said "son, you're gonna turn that case into scrap." He showed me how to feel the thread stretch and back off half a turn on certain bolts. Now I save like 20 minutes per engine and I haven't cracked a single case since. Anyone else get a reality check from an old hand?
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masondixon
masondixon22d ago
Torque specs exist for a reason, you're just bypassing engineering that keeps things from backing off at altitude. Half a turn too loose on the wrong bolt and that engine is coming apart over Lake Michigan.
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skyler_kim
skyler_kim21d ago
Wait, are we arguing about torque specs or about who's got the scarier "that one time" story? I've definitely torqued things to "that feels about right" on my own car and only had them rattle loose once, which I'm pretty sure doesn't count as a real failure. But hey, as long as we all agree Lake Michigan is a really bad place to test your backyard engineering, I'm with you.
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the_felix
the_felix21d agoProlific Poster
Used a similar trick on radial engines out at Arctic Air years ago. Old timer told me to torque the jug hold-downs to spec then back off an eighth turn so the studs don't snap in the cold.
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