Drain tube in cylinder assembly

[shawnd]

While my cowling motor is away getting overhauled and the cowling is off, I am taking the opportunity to familiarize myself with the TSIO360MB6B engine. And while browsing, I found the drain tube from cylinder #5 disconnected - not sure how. Is this concerning? Based on the service manual from TCM, an A&P should be able to put in a new compression seal (#45) and tighten and torque the nut to the male connector (#19)? The head of the drain tube looks intact as far as I can see.

 

 

 

 

 

 

 

 

 

[carusoam]

Shawn,

I’m not familiar with your engine.... but,

That appears to be the drain tube for excess 100LL...

Note the bluish color that has leaked out of it?

It would be good to have all the drain tubes properly installed....

Disconnected drain tubes allow air to come in as well as fuel drops to get out...

See if it goes to something called a ‘sniffle valve’ at the bottom of it...

Check all the tubing and nuts and bolts while you have unfettered access...
 

Nice catch!

PP thoughts only, not a mechanic...

 

Best regards,

-a-

[kortopates]

That's an induction leak and yes you want to repair that asap. The drain fitting (# 19) that the tubing connects too was probably very recently replaced for the TCM service bulletin to remove the primer diverter valve for a newer style. That may have something to do with facilitating that - or not.

 

 

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[shawnd]

I am going to go back tomorrow and disconnect the nut and inspect it to see if the tube sheared and if there's a piece left in there. If so, need to create a new lip. Anyone know what tool I might need? I would need to check with the A&P if he has one, if not, probably have to buy one.

[EricJ]

1 hour ago, shawnd said:

I am going to go back tomorrow and disconnect the nut and inspect it to see if the tube sheared and if there's a piece left in there. If so, need to create a new lip. Anyone know what tool I might need? I would need to check with the A&P if he has one, if not, probably have to buy one.

A pipe flaring tool, but there is a difference in the flare angle between aviation and automotive, so you need to get the aviation-compatible flaring tool.

 

[carusoam]

Aluminum flaring isn’t usually very difficult...  to mess up, or to do correctly... 

If it takes too much practice, you may need a new tube...

The pic is a bit low res... but, it doesn’t look cleaved off.  And.. it does look like the drawing....
 

Odd that it escaped with the retaining nut still in place...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Guest]

11 hours ago, shawnd said:

I am going to go back tomorrow and disconnect the nut and inspect it to see if the tube sheared and if there's a piece left in there. If so, need to create a new lip. Anyone know what tool I might need? I would need to check with the A&P if he has one, if not, probably have to buy one.

The small bead on the end of the tube look correct to me, they aren’t a typical tube flair.  I’d buy 6 new seals plus a few spare and replace them all.

Clarence

[shawnd]

Finally got to the hangar and took the nut off. I didn't find any aluminum sheared inside between the nut lip and the compression seal. However, the nut slides around the flair which doesn't seem like was the intended design. I imagine the flair at the tip of the aluminum drain tube should prevent the nut from sliding off the drain tube assembly - correct? Curious if there is a way to get this back into service without redoing the flair at the end of the tube end or replacing the whole drain tube assembly.

Got high resolution and well lit pictures this time around.

 

 

 

[Guest]

The nut should slip back on the tube over the flair/bead.  Slip the new seal onto the tube, push the tube into the fitting in the head, run the nut onto the fitting, this will compress the rubber seal onto the tube holding in in place.

The seal in your picture is old and rotten causing it to loosen its grip on the tube.

Clarence

[carusoam]

Expect to want to change out all six of the rubber pieces...

That one looks terrible... The other five are probably the same age...

Great pics!

There probably is a good torque for tightening the nut back on... it will compress the rubber and tighten the nut at the same time...

The decayed rubber bits looks like an interesting means of delivering bits back into the air intake... probably not a significant issue...

PP thoughts only, not a mechanic...

Best regards,

-a-

[shawnd]

7 hours ago, M20Doc said:

The nut should slip back on the tube over the flair/bead.  Slip the new seal onto the tube, push the tube into the fitting in the head, run the nut onto the fitting, this will compress the rubber seal onto the tube holding in in place.

My 6 new compression seals are coming in tomorrow. @M20Doc Thanks for clarifying. I think what you are saying makes sense now. With "Slip the new seal onto the tube", the flair end of the tube is pushed/pressed into the seal which is then locked in place when the nut is tightened to the male connector and compresses the seal. It's the seal's width that prevents the tube from falling through the nut.

I have never seen something like this and thought it was like the rest of the flair style pipe fittings. With the new seal in hand, I am hoping it will make more sense.

 

[shawnd]

Thank you folks! It was exactly as you described @M20Doc. The seal sits below the flair and you push the flair end up into the head with the seal behind it. Tighten the nut up and everything stays firmly in place. @carusoam got all 6 replaced and nuts torqued to spec.

While mucking with the cyl #1 drain, discovered my EGT1 clamp was loose and looks like I am missing the stainless steel clamp thimble piece; so a call to JPI is next. From their picture, you can see the washer and thimble (?) so should be easy to acquire.

 

My A&P reviewed all of this btw.

[shawnd]

Purchased new thimbles and washers for the EGT probe and its secured to the exhaust. Not sure how it got to the state it was in prior but glad its fixed!

[carusoam]

There isn’t anything in a more harsh environment than the pipes between the exhaust valve and the TIT sensor...
 

Evidence of their age and wear is important to monitor...

The pipes actually thin over time...

The EGT sensor is in the depth of the harsh environment...

The TIT sees that depth X 6....

Sort of an explanation of why TIT sensors need replacement every now and then...

PP thoughts only, not a mechanic...

Best regards,

-a-

[shawnd]

Good points! The whole exhaust and turbo system was inspected during purchase and was given the green light. Though probably going to keep an eye on it every annual given the age. The turbo transition, where the different exhausts combine and where the TIT probe sits, is likely the most critical of the whole system.  It can thin out and swell from chatting with Frank @ Chandler Aviation.

Thanks again @M20Doc and @carusoam for the help.

[Guest]

2 hours ago, shawnd said:

Good points! The whole exhaust and turbo system was inspected during purchase and was given the green light. Though probably going to keep an eye on it every annual given the age. The turbo transition, where the different exhausts combine and where the TIT probe sits, is likely the most critical of the whole system.  It can thin out and swell from chatting with Frank @ Chandler Aviation.

Thanks again @M20Doc and @carusoam for the help.

Buy a shop vacuum, fashion a plastic plug that will fit in snugly into the tail pipe, bore a hole in the centre of it that will fit the vacuum hose snugly, plug the hose into the blow or discharge side of the vacuum cleaner.  When the cowl is off for an oil change pressurize the exhaust system then spray all of the joints and welds with soap and water to find cracks and leaks.

Soak all of the slip joints and wastegate with mouse milk.

Clarence