Exhaust Manifold Studs

[rotaxflyer]

I have a problem with a couple exhaust manifold studs unscrewing from the engine on their own. They seem to hold just fine when screwed back in so I am reluctant to go oversize. Should I try some Loctite 246 (medium strength/ high temp)? lock washers? Spring washers? Serrated?

[fearofpavement]

Re: Exhaust Manifold Studs

I wouldn't lose much sleep over the studs coming out. Screw them back in an be thankful one didn't break off flush with the cylinder. Loctite would probably work to retain them but if the next time you take your exhaust off they come out again you still don't have a problem.

Unless you are talking about them studs coming out on their own without your help, ie loose exhaust. If that is what you mean then yes you need to take measures to retain them as exhaust leaks are bad things. (first cousins of engine fires) Are you getting adequate torque on them during installation?

[rotaxflyer]

Re: Exhaust Manifold Studs

Oh it is happening in flight I'm going to try lockwashers first.

[Pearson]

Re: Exhaust Manifold Studs

rotax flier,

I don't know how you are putting the studs in, but if they go in easy, they will obviously come out easily. Are you screwing them in by hand?

If so, try jamming a couple of nuts together on the end that sticks out. Then use a socket or wrench on the outter nut to tighten the stud in. After you get it tight, use two wrenches to separate the nuts and throw them away.

If you use the blow proof gaskets you won't have to mess with these studs until the next overhaul. Those cheap thin gaskets are a joke.

[rotaxflyer]

Re: Exhaust Manifold Studs

Thanks, I'll try the double nut method.

Andy Sinnamon

[astjp2]

Re: Exhaust Manifold Studs

Locktite should work, just give it time to set up, I have done it dozens of times on lots of airplanes. I have even helicoiled the jug and installed new studs with locktite. Good luck Tim

[Forrest Barber]

Re: Exhaust Manifold Studs

studs can be obtained that are .001 , .003 oversize and I still use lock tite.