Oil leak on governor mounting stud

[Bubblehead]

We reinstalled the stud with Loctite 271 Wednesday night, and reinstalled the governor (with plate and gaskets!) last night and did a leak check.  I ran the engine for about 5 minutes with the prop at high-rpm and warmed up the oil to about 140F.  No leak.  Slowly brought the prop lever back to raise pressure to the prop and perhaps put more stress on the system.  Ran with about a 200 rpm drop for about 3 minutes and still no leak.  We shut everything down, put the cowling on and I'll test fly over the weekend to see if the leak returns.  At this point the results look promising.

[carusoam]

As part of your testing, see if you can measure the temperature around the stud.  It will be hard to ascertain, but helpful to know.

It probably can't get any higher than the oil that is coursing through it.

only PP ideas, not a mechanic.

Best regards,

-a-

[Guest]

5 hours ago, Bubblehead said:

We reinstalled the stud with Loctite 271 Wednesday night, and reinstalled the governor (with plate and gaskets!) last night and did a leak check.  I ran the engine for about 5 minutes with the prop at high-rpm and warmed up the oil to about 140F.  No leak.  Slowly brought the prop lever back to raise pressure to the prop and perhaps put more stress on the system.  Ran with about a 200 rpm drop for about 3 minutes and still no leak.  We shut everything down, put the cowling on and I'll test fly over the weekend to see if the leak returns.  At this point the results look promising.

What torque value did you use?  Mooney or Lycoming 

Clarence 

[carusoam]

That's probably an RV-8, doc.  Check the OP...

But, if the Mooney spec makes more sense...?

Best regards,

-a-

[Guest]

Yes, but links to both a Mooney and a Lycoming SI have been posted in this thread, these engines cross many lines.  In my experience, lack of correct torque and correct hardware has as much to do with the leaks as anything.

Clarence

[Piloto]

11 hours ago, Bubblehead said:

We reinstalled the stud with Loctite 271 Wednesday night, and reinstalled the governor (with plate and gaskets!) last night and did a leak check.  I ran the engine for about 5 minutes with the prop at high-rpm and warmed up the oil to about 140F.  No leak.  Slowly brought the prop lever back to raise pressure to the prop and perhaps put more stress on the system.  Ran with about a 200 rpm drop for about 3 minutes and still no leak.  We shut everything down, put the cowling on and I'll test fly over the weekend to see if the leak returns.  At this point the results look promising.

We are in sync. Did exactly the same thing today but ran the engine for 20 minutes at high and low rpm, no leaks. Will test fly tomorrow. Will keep you posted.

José

[Piloto]

Flight tested the engine today, NO LEAKS. The exhaust pipe joint were it would start dripping into showing the leak was bone dry. Bubblehead info was the key to the success, Thanks. It appears that the overhaul shop never installed the spacer and extra gasket when the governor was first installed. The reason it didn't leak for over 700hrs was because the screen gasket was installed with silicon sealant. As the sealant deteriorated leaks started showing up even after re torqueing the nuts. I first replaced the screen gasket with no sealant and it leaked like before. After putting the spacer and extra gasket no leak. Talking to a local mechanic he mention that this is not uncommon because when you pull the old gaskets and spacer together they look like a single gasket.

José

[Browncbr1]

15 hours ago, Piloto said:

Flight tested the engine today, NO LEAKS. The exhaust pipe joint were it would start dripping into showing the leak was bone dry. Bubblehead info was the key to the success, Thanks. It appears that the overhaul shop never installed the spacer and extra gasket when the governor was first installed. The reason it didn't leak for over 700hrs was because the screen gasket was installed with silicon sealant. As the sealant deteriorated leaks started showing up even after re torqueing the nuts. I first replaced the screen gasket with no sealant and it leaked like before. After putting the spacer and extra gasket no leak. Talking to a local mechanic he mention that this is not uncommon because when you pull the old gaskets and spacer together they look like a single gasket.

José

 

You used loctite 271 on the stud also?

[Bubblehead]

He did not have a leak at the stud.  His leak was caused by there not being the proper Lycoming-required .040 spacer plate installed.

[Piloto]

1 hour ago, Browncbr1 said:

 

You used loctite 271 on the stud also?

I never removed the studs but after viewing here the issues with the studs I applied a bit of PRC 1422 A at each stud threads next to the flange to seal them.

Its amazing the amount of knowledge you can quickly acquire through forums like this. Thanks to all.

José 

[Bubblehead]

Just got home from a 30 minute test flight and there is no sign of a leak anymore.  Rain prevented me from flying a second, longer flight but I feel very good about the Locktite 271 on the stud.  

My thanks to everyone who chimed in with information, opinions, references and even guesses.  I consider this to have been a collaborative effort and a group success.  I will update this thread in a couple of weeks if all continues satisfactorily and sooner if it doesn't. 

[Browncbr1]

I'm glad this conversation came up because I'm going to need to figure out why I keep getting oil on the inside of my right cheek and on my exhaust pipe.  I think it might be from my right mag case seal though.  

[carusoam]

Check mag bolts/nuts for tightness...

Some have been known to become loose just by somebody re-using the star lock washers.

On of the First signs would be oil dripping from it.  Next sign could be the mag coming loose.  So give it a tug....

Best regards,

-a-

[Browncbr1]

53 minutes ago, carusoam said:

Check mag bolts/nuts for tightness...

Some have been known to become loose just by somebody re-using the star lock washers.

On of the First signs would be oil dripping from it.  Next sign could be the mag coming loose.  So give it a tug....

Best regards,

-a-

Already gave it a good tug.  And I supervised the previous install using new washers.  It seems like there is a flange that sits between the mag and the case with a gasket in between the flange and the case.  I'm wondering if that is the culprit.  It drips on the #3 intake riser flange and bolt.  That's rather high up for it to be coming from the prop gov. 

[Guest]

3 minutes ago, Browncbr1 said:

Already gave it a good tug.  And I supervised the previous install using new washers.  It seems like there is a flange that sits between the mag and the case with a gasket in between the flange and the case.  I'm wondering if that is the culprit.  It drips on the #3 intake riser flange and bolt.  That's rather high up for it to be coming from the prop gov. 

It would be hard to see how a leaking magneto flange gasket would show up on the intake flange and bolt.  In the past I've seen incorrect gaskets used between the magneto spacer and the spacer and the magneto.  

The wrong gasket can lead to the magneto falling off. Check it carefully.

Clarence

 

 

[Browncbr1]

I don't know where else the oil could be coming from.  I'm going to have another look this afternoon though.   Engine has a little over 500 smoh.  I can see clearly that the mag is secured and not leaking.  If anything is leaking there, it is the gasket between the flange and case.  The only other thing I can think of leaking that high up is the oil bypass valve.  Thank you for the warning clearance.  I ordered an air hose degreaser gun to spray 100LL and get everything good and dry to have a better chance and finding the leak(s).  I'll report back

Edited November 7, 2016 by Browncbr1

[carusoam]

There are a couple of various threads on leak finding.... with products like UV dyes for the oil and dry powders that will make the oil leak more visible.

Use caution with spraying 100LL around, that doesn't sound like a good idea. There are other less combustible solvents that do this job. Sounds more like a tremendous flame thrower...  

That could put an end to your current issue...

Maybe I just missed something...  

Best regards,

-a-

[Browncbr1]

Flame thrower indeed if one were to spray on a hot engine or hot electrical circuits!  Anyhow, all the ferries around here do this and it cleans things up pretty well. .  This isn't a recommendation to anyone though.  

[Piloto]

On ‎11‎/‎6‎/‎2016 at 8:07 PM, Browncbr1 said:

Already gave it a good tug.  And I supervised the previous install using new washers.  It seems like there is a flange that sits between the mag and the case with a gasket in between the flange and the case.  I'm wondering if that is the culprit.  It drips on the #3 intake riser flange and bolt.  That's rather high up for it to be coming from the prop gov. 

Sounds like a leak from the push rod shroud tubes. I had a similar leak. Cleaned with MEK the shroud tubes at the cylinder top end and with a small brush coated the tubes with PRC 1422 A. No leaks after that.

José

[Guest]

On November 7, 2016 at 9:36 AM, Browncbr1 said:

I don't know where else the oil could be coming from.  I'm going to have another look this afternoon though.   Engine has a little over 500 smoh.  I can see clearly that the mag is secured and not leaking.  If anything is leaking there, it is the gasket between the flange and case.  The only other thing I can think of leaking that high up is the oil bypass valve.  Thank you for the warning clearance.  I ordered an air hose degreaser gun to spray 100LL and get everything good and dry to have a better chance and finding the leak(s).  I'll report back

100LL is a very good cleaner, it cuts oil very well.  I would not use it with an air sprayer, a simple plant sprayer works quite well.

It sounds like you may have a leaking shroud tube, a very simple fix, a few new seals, a shroud tube lock tab and a rocker cover gasket are all that is needed.

Clarence

[Piloto]

22 minutes ago, M20Doc said:

100LL is a very good cleaner, it cuts oil very well.  I would not use it with an air sprayer, a simple plant sprayer works quite well.

It sounds like you may have a leaking shroud tube, a very simple fix, a few new seals, a shroud tube lock tab and a rocker cover gasket are all that is needed.

Clarence

AVGAS will dissolve oil but leaves a film residue that inhibit sealant adhesion. I prefer to use MEK in a metal oil squitter to spray on a surface. MEK removes oil leaving no residues and evaporates quickly.

José

[Guest]

That may be true concerning 100LL residue.  But I'm talking about removing the oil then replacing the seals, not sealing with PRC.

Clarence

[mooniac15u]

12 hours ago, Browncbr1 said:

Flame thrower indeed if one were to spray on a hot engine or hot electrical circuits!  Anyhow, all the ferries around here do this and it cleans things up pretty well. .  This isn't a recommendation to anyone though.  

When spraying a liquid like gasoline you can build up a significant static charge.  You don't even need a hot engine or hot electric circuit, the static build up can cause the needed spark.  If possible you should ground your sprayer to the engine or airframe before spraying.

[Browncbr1]

Thanks for all the warnings guys.. I appreciate everyone looking out for each other's safety.

I pulled the cowl off yesterday and found some wetness around the oil pressure relief valve... I just gave it a little half-grunt torque.   All push rod housings are dry..

One way or another, I will need to clean all the oil off the engine before making any kind of determination as to where it is coming from.  I think it's just a little coming from a number of places.. 

 

Piloto, I think you are correct about LL film.  I also used MEK when I addressed my previous case leak.  I just prefer to use 100LL to get most of the oil off sense MEK eats plastic and rubber.

[N601RX]

Anywhere that sells lycoming parts has them.  If I remember correctly just add a P003 to the end of part number. Check with aircraft specialties or call aero in stock.