Oil leak on governor mounting stud

[Bubblehead]

Thanks for the info on the oversized stud. I did not go that route. I think putting an oversized stud in aluminum risks cracking the aluminum accessory case. 

I now have over 6 hours of flight time since installing the stud with Locktite 271 and there is not a hint of oil on the belly of the plane. I hereby declare success on solving the oil leak. 

My thanks to everyone who offered suggestions and information.  I have learned a lot from this.

[Bubblehead]

My how time flies. I came across my link to this forum and thread and thought I'd post "the rest of the story." This oil leak problem occurred in 2016 and never re-appeared, so with the help of the posters we solved the problem. 

In fact, I flew this plane about 100 hours a year until early 2020 when I sold it. In 2019 I took the plane from Texas to Alaska and back on a month long vacation. The problem never appeared again. 

My thanks again to all who helped me troubleshoot it, come up with correction options and gave moral support. 

Edited March 3, 2021 by Bubblehead

[carusoam]

Fantastic follow-up @Bubblehead!

it’s never too late to add more detail around here.

Best regards,

-a-

[Josuev]

On 10/29/2016 at 9:36 AM, Bubblehead said:

I have an O-360-A1F6D engine on my RV-8.  I know that is not a Mooney but I have learned a lot from reading this forum, and this engine is used on Mooneys so I hope I am not violating any rules.

In early summer the engine developed an oil leak. We finally narrowed the source down to the prop governor area and changed gaskets a couple of times but the leak continued.  We do have the Lycoming required spacer plate and correct gaskets.  This week I had the governor bench tested at Byam Propeller Service in Fort Worth, TX but the governor itself was not leaking.  BTW the people at Byam are fantastic.

 

My mechanic decided that maybe we had a leak along a stud and upon inspection found the lower outboard stud was a little loose, and when he removed the stud he found that the stud was not in a blind hole but was partly exposed to the oil in the accessory case and maybe in the flow of the oil return line!

 

We pulled the stud out and it was clean with no sealant of any kind.  Normally I would expect a stud to be put in with at least Loctite. Perhaps the sealant got carried away after all these years.  BTW the engine has 1000 hours SMOH but the prop governor has never, to my knowledge, been overhauled. 

 

1) Should the stud be open to the return flow and oil in the accessory case?  If not then I have an accessory case problem.

2) What sealant/thread lock should we install the stud with?

3) Have others had this problem, and if so, how did you eliminate the oil leak?

 

Remember this is a dual mag engine and the governor mounting pad is integral with the accessory case.  Non-dual mag engines have a separate adapter.  Attached is a picture of the governor mount.  The lower right hand stud is the one that seems to be leaking.

 

Thanks for the help.

How did you get it resolved.?