Exhaust Stud Torque

Notatestpilot

Notatestpilot

Pre-takeoff checklist
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Aug 31, 2020
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Notatestpilot
If an O540 engine exhaust stud uses a 5/16-18 thread nut, what is the required torque?
What does the overhaul manual call out?
 
Notatestpilot said:
If an O540 engine exhaust stud uses a 5/16-18 thread nut, what is the required torque?
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Lycoming lists torques in the SSP-1776. TCM used to have a Service Bulletin with all the torques but I think they moved them into the M-0 Standard Practices manual which I can't get to link at the moment.
 
There is no specific torque value for exhaust flange nuts listed in the current Lycoming engine manuals I’ve read. That sends you to the standard torque table for 5/16” nuts, which is 17-19 pound feet of torque. Most mechanics I know disregard that and tighten to snug fearing warping of exhaust flanges. That’s why guys lose exhaust nuts. I tighten mine per the standard torque table and use Nord-Lock washers. Mine stay put.
 
Stewartb said:
There is no specific torque value for exhaust flange nuts listed in the current Lycoming engine manuals I’ve read. That sends you to the standard torque table for 5/16” nuts, which is 17-19 pound feet of torque. Most mechanics I know disregard that and tighten to snug fearing warping of exhaust flanges. That’s why guys lose exhaust nuts. I tighten mine per the standard torque table and use Nord-Lock washers. Mine stay put.
Click to expand...
Thank you sir. Didn't know about Nordlock. I shall check it out...
 
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