Exhaust Crack

[FlyDave]

Wow Lance - that's scary!

I change my oil every 25 hours and each time pressurize the exhaust system and look for cracks with soapy water. I haven't found any cracks or leaks yet. I hope I would find one long before it get's that bad.

[Tony Armour]

Jig for letting your neighbor (that took a welding class in high school) weld up your exhaust :-)

 

 

 

 

[moxfox]

At every oil change , 25 hour I do the mouse milk thing and check for cracks with compressed air , shove a air nossle up the tail pipe with some rags around it spray soapy water around all of the welds to see if there are any cracks. This is. What my mechanic told me to do. This is the same as FlyDave dose!

Edited January 8, 2016 by moxfox
Added on

[carusoam]

Thanks for the reminder of how that is done, mox.

Good to know for the TC crowd.

Best regards,

-a-

[mike_elliott]

On ‎1‎/‎7‎/‎2016 at 9:12 PM, LANCECASPER said:

A crack was noticed on my exhaust pipe 

Number 7 on the diagram

 

The crack didn't look so bad on the tailpipe when it was on the engine. But it turns out after it was taken off that it was only being held together by about 30% of the weld.

 

Here's my shiny new tailpipe

I don't like to think about what would have happened if that had separated in flight.

This is an area that should be looked at every oil change on the Bravo. Yours is not the first one that has cracked right there.

[LANCECASPER]

1 hour ago, Hyett6420 said:

I was speaking to my a and P about tuned exhausts the other day as I think it would be great for my J. His view was don't change the exhaust until it cracks or needs a fix.  So my advice would be go and look at www.powerflowsystems.com.  Gives you more power, less fuel flow for nothing as it would pay for itself over time. 

Your exhaust is cracked, so why fix it, when you can get a new tuned one for the same ish money.

They don't make one for the M20M.

[ZamF16]

I have owned my Bravo for almost five years now, and have had a small crack in the exhaust near the turbo, every annual.  It has always been in a slightly different place and small, but there none the less.  I figured it was the age of the exhaust and the heat of the turbo.  Luckily, it had never been as bad as your pictures.

[carusoam]

On the high pressure side of the turbo, leaks are more dangerous.  The uncontained high pressure / high temperature exhaust stream can act like a cutting torch inside the cowl.  The photos above show a major failure of a weld seam.  Broken/reused Bravo exhaust clamps have caused some additional known failures.

I would want to know what An acceptable crack is before continuing to fly with an unknown challenge.

Zam, know what I'm getting on about? (If not, see Andy's post below...)

I'm not a mechanic, but I have read a lot of MS grief about exhaust systems....

Best regards,

-a-

[Awful_Charlie]

After the first couple of repairs (which didn't have the greatest longevity),every time I've found a crack (and I have a good peer about at the 25 hour oil change, typically finding them when they are less than 1/4", always on the welds) I get it repaired with a gusset rather than just getting the weld re-done. The Lycoming exhaust is certainly not great for robustness despite working a little mouse milk into the slipjoints at oil change. The last time round I got fed up with the frequent repairs, so got gussets added at all the points the welder thought looked fragile - it's held up for 2 years/200hours now without another intervention

[LANCECASPER]

1 hour ago, Awful_Charlie said:

After the first couple of repairs (which didn't have the greatest longevity),every time I've found a crack (and I have a good peer about at the 25 hour oil change, typically finding them when they are less than 1/4", always on the welds) I get it repaired with a gusset rather than just getting the weld re-done. The Lycoming exhaust is certainly not great for robustness despite working a little mouse milk into the slipjoints at oil change. The last time round I got fed up with the frequent repairs, so got gussets added at all the points the welder thought looked fragile - it's held up for 2 years/200hours now without another intervention

would be great to see a picture

[jlunseth]

I have been lucky with my 231, knock on wood.  When I first bought it my mechanic found two nicks in the exhaust.  There is a sheet metal heat shroud over the exhaust at a couple of locations and it had been allowed to just slowly migrate inward until it touched the collector and began to notch it.  They were tiny.  About the width of a fingernail.  He wouldn't let me fly without fixing it.  I didn't argue.  But that has been it.  

[Awful_Charlie]

8 hours ago, LANCECASPER said:

would be great to see a picture

I don't intend to drop the cowl just for the sake of some photos, so you'll have to wait until the next oil change - late May is when I'm expecting that to arrive

[AndyFromCB]

Nothing a little JBWeld won't fix ;-) I would strongly recommend a little tug on the exhaust pipe before each flight. If that turbo detaches itself in flight, say your prayers and just dive down. You'll be equally dead, but at least it won't be as painful as being burnt to a crisp.

Edited April 17, 2016 by AndyFromCB

[Awful_Charlie]

Pics as promised - it looks as though I spoke too soon, and the #2 repair is going to need a touch soon:

#1 #3 #5

#2 crossover

[jetdriven]

On April 17, 2016 at 1:45 PM, AndyFromCB said:

Nothing a little JBWeld won't fix ;-) I would strongly recommend a little tug on the exhaust pipe before each flight. If that turbo detaches itself in flight, say your prayers and just dive down. You'll be equally dead, but at least it won't be as painful as being burnt to a crisp.

Pull the mixture and you likely fix the emergency, only to be faced with another, equally serious one. But perhaps more survivable. 

[LANCECASPER]

10 hours ago, Awful_Charlie said:

Pics as promised - it looks as though I spoke too soon, and the #2 repair is going to need a touch soon:

#1 #3 #5

#2 crossover

Thanks!!

[tls pilot]

Recently had the flange w hole in it -going into the transition of turbo from #4 into transition 

used ACORN in CN to get the part and clamps

super fast service and fair prices. Also use Plane exhaust in FLL but found acorn to be very fast and knowledgable