I purchased a freshly overhauled O-145. It blew a head gasket in four hours. It pulled a stud out of the head. The mechanic helicoiled the head and replaced the gasket. Four hours later, the same head gasket is leaking. The mechanic tightens the nuts to 140 inch-pounds. This is the standard torque for 5/16 nuts that are 24 tpi. I have been unable to find any Lycoming specification for torque for the head. The mechanic is coming back next week to remove the head and replace the gasket and possibly replace the head.
What do others use for torque on these nuts, and were you successful?
What do others use for torque on these nuts, and were you successful?
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