M20K 231 Turbo oil supply lines... sealant at the turbo?

[SkepticalJohn]

Is there a loctite type substance that's located on the threads where the oil supply T screws into the turbo of a 231?

There is a T that screws into the turbo and two lines that screw into that T (one is oil supply and the other goes to a pressure transducer). I'm wondering if there is some sort of loctite in there because I don't see any safety wires. That li'l turbo gets awful hot for loctite. I guess those lines are carrying oil so they can't be over a 300 hundred degrees or so... anyways, what holds it together?
 
John
 
 

[DanM20C]

They are tapered pipe threads, they seal by creating an interference fit as they are tightened.  The interference fit locks them in place pretty good and the hoses themselves would provide the "safety" as they would have to fail for the fitting to back out. 

Cheers,

Dan

[SkepticalJohn]

Pardon the awkward angle - I'm no photographer. On the left side of the photo, it looks like there's some smutz between the 90°fitting and the T. Could it be possible someone put something in there to assist the interference fitting? 

[DanM20C]

I’m not familiar with the approved aviation sealants, but yes.  Likely there is something on the threads.  With pipe threads this is usually a type of sealant, but not a locking agent like loctite.  I have been known to be wrong though. 

Cheers,

Dan

[kortopates]

Since it may not be obvious if you bought the aircraft this way,  you should be aware this is not a standard installation. Someone modified the installation; presumably perhaps to do some diagnostic testing. I assume yours is a unique mod. But you should be able to go to http://continentalmotors.aero/support/illustrated-parts-catalog.aspx and enter your engine (e.g., TSIO-360-LB etc) and navigate to the Turbo section and see the original configuration which just had an outlet and inlet hose going to the turbo. The actual pipe to hose fitting on the turbo may not be listed there if its part of the turbo itself, in which case you could inquire with Mainturbo.com and even buy a new fitting from them if desired. 

Also I'd check your logs to see if you have an entry for this modification. If not that should be motivation to go back to the original. This is certainly not part of Merlyn or Intercooler modification either. My guess is someone had a bad experience with a check valve clogging and cutting off oil to the turbo and decided this (perhaps unapproved) modification was the solution. I am skeptical and it looks like more trouble. The turbo gets its oil off an engine oil galley on the side of the engine and then goes through a one way check valve to the turbo. Changing your oil regularly should avoid any chance of the check valve clogging if that was the issue. (I can only speculate).

All approved sealants are listed in Continental's M-0 maintenance manual. You probably won't find that for free on the internet, but since M-0 replaced the majority of all the SB, SI's you could also search for a copy of SIL99-2C which you should find easily. Its the original SIL that list all the approved sealants, lubricants, adhesives; which is now superseded by M-0

Edited March 3, 2018 by kortopates

[SkepticalJohn]

Outstanding, thanks folks. I'm now thinking it could just be some sort of witness mark. I'll do a search and see what I find. 

[DanM20C]

My Rayjay 231 has the same T fitting.  I think this might be standard on the rayjay 231’s?  

@jlunseth maybe can shed some light?

Cheers, 

Dan

[kortopates]

32 minutes ago, DanM20C said:

My Rayjay 231 has the same T fitting.  I think this might be standard on the rayjay 231’s?  

@jlunseth maybe can shed some light?

Cheers, 

Dan

You're right, I stand corrected.  The Continental server seems to be down for me right now which is why I missed this earlier. But your comment inspired me to look it up in my paper copy of the IPC and indeed there is a AN917-1 tee fitting coming off the turbo and a continental 631310 elbow on the Tee. It doesn't show anything but the one check valve hose connected to the tee though - so I can't tell exactly what function it serves to be there permanently and I've never seen an oil pressure reading for the turbo provided in the cockpit of any 231. So maybe its normally capped off. But regardless I was in error to suggest its non-standard. You could try some Loctite 565 Adhesive Sealant on the pipe threads.

Edited March 3, 2018 by kortopates

[DanM20C]

1 hour ago, kortopates said:

You're right, I stand corrected.  The Continental server seems to be down for me right now which is why I missed this earlier. But your comment inspired me to look it up in my paper copy of the IPC and indeed there is a AN917-1 tee fitting coming off the turbo and a continental 631310 elbow on the Tee. It doesn't show anything but the one check valve hose connected to the tee though - so I can't tell exactly what function it serves to be there permanently and I've never seen an oil pressure reading for the turbo provided in the cockpit of any 231. So maybe its normally capped off. But regardless I was in error to suggest its non-standard. You could try some Loctite 565 Adhesive Sealant on the pipe threads.

Thanks Paul. I was worried I had another thing to fix. 

The T is there to supply an oil pressure transducer.  That is where the engine oil pressure is taken from.

Cheers,

Dan

[kortopates]

2 hours ago, DanM20C said:

Thanks Paul. I was worried I had another thing to fix. 

The T is there to supply an oil pressure transducer.  That is where the engine oil pressure is taken from.

Cheers,

Dan

Interesting as its unusual, most Continentals  have the transducer on the other end of the hose tee'd  off the oil galley, which would be the same oil galley supply oil to the turbo. Most lycoming's have it right after the oil pump and regulator where it reads the highest oil pressure and they do run with higher oil pressure accordingly compared to Continentals.  

[DanM20C]

47 minutes ago, kortopates said:

Interesting as its unusual, most Continentals  have the transducer on the other end of the hose tee'd  off the oil galley, which would be the same oil galley supply oil to the turbo. Most lycoming's have it right after the oil pump and regulator where it reads the highest oil pressure and they do run with higher oil pressure accordingly compared to Continentals.  

I thought it was a strange location too.  I figured it would make more sense to locate it on the other side of the hose near the supply oil gallery.  Apparently others figured the same.

Cheers,

Dan

 

[N231BN]

That is the standard location for a 231.