Stripped exhaust stud thread

[coxcub]

I've just changed the muffler on the O320 in my SC and when tightening the outboard flange nut on the #3 cylinder stack the stud pulled out bringing the thread from the cylinder with it!

Anybody had this problem? and if so does anybody know of an approved scheme to insert a coil? maybe with a small jig so that the hole can be accurately drilled and tapped without removing the cylinder - It's probably the easiest one on the engine to do in situ.

Thanks in advance for any advice and info

 

[behindpropellers]

Heli-Coil is your best option.

www.mcmaster.com has nice kits with everything you need.

Tim

 

[Fortysix12]

I like to change the hardware (nuts and shake proof washers) at every inspection(that is if I'm removing the exhaust). Chances are it wont happen again. Sometimes a frozen nut on a bolt gets used in this configuration which most likely caused this failure. If you have any nut and studs that are fused together throw them away and replace with all new hardware. New Lycoming exhaust studs. They are special. Are you familiar with using a jam nut system to install the studs?

 

[cubscout]

Good responses from Tim and from 46-12.

Another thought: Consider dripping some "Mousemilk" solvent on the moving parts (q.v., a recent image posting in another context) a few hours before you plan to remove exhaust nuts. Then put on some more, and some more.

This seems to loosen things up better than most other solvents.

And then use new hardware.

Let us all know how your repair goes, eh? These things can be a pain.

Thanks. cubscout

 

[Jacques]

Speanaur Page :C214
E-Z LOK 1/2'' X 5/16'' the best job, and very easy installation for tie job.
Jacques[/url]

 

[bushmaster]

Hey Jacques you been out caribou hunting yet. How is the snow up your way

 

[coxcub]

Thanks to all - Helicoil did the trick.