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Lyc 390 case bolt torque

IO-390 Case Bolts and Studs

Don,
The basic values are:
1/2" thru-studs: 600 in.-lbs
3/8" nuts: 300 in.-lbs
1/4" nuts and capscrews: 96-108 in.-lbs
1/4" shear nuts: 55-60 in.-lbs

There's a specific sequence for torquing case bolts and studs in Section 8 of the IO-390 Lycoming Operation Reference Manual; this is a small ring binder that is sent with with engine.

Send me an email and I will scan the pages for you.

Best,
Mike
 
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