Monster in my muffler?

[47U]

I was horrified by the monster… what did he do with my baffles?  Eat them?

A trip over to Knisley for a new PMA’d exhaust… 2.5 amu later, all good.

 

[David Lloyd]

A trick it happened, a treat you found it.

[Ragsf15e]

4 hours ago, 47U said:

I was horrified by the monster… what did he do with my baffles?  Eat them?

A trip over to Knisley for a new PMA’d exhaust… 2.5 amu later, all good.

 

i’ve never had to do this yet, but I’m curious why you went with a new one instead of having AWI or some other shop repair your old one? I thought there was a significant price difference?

[47U]

5 minutes ago, Ragsf15e said:

I’m curious why you went with a new one

My #3 riser was the only one that had any life left in it.  Knisley had made me a new #3 (maybe) 10 years ago when the flange cracked.  I discovered at that time that my muffler didn’t fit the template; Knisley had to custom fit the riser to make it work, at no extra charge.  They also rebuilt (reusing only the flange) a tailpipe a few years ago when the seam cracked.  But, the deciding factor was the muffler was no longer rebuildable.  Knisley is local to me and they do exceptional work.  

I might have gone Power Flow, but I’m still running a generator.  I would have had to do an alternator conversion to make it fit.   

[EricJ]

Mine has no firetube left at all.   My hangar neighbors say it sounds pretty cool.   

[bcg]

My #3 riser was the only one that had any life left in it.  Knisley had made me a new #3 (maybe) 10 years ago when the flange cracked.  I discovered at that time that my muffler didn’t fit the template; Knisley had to custom fit the riser to make it work, at no extra charge.  They also rebuilt (reusing only the flange) a tailpipe a few years ago when the seam cracked.  But, the deciding factor was the muffler was no longer rebuildable.  Knisley is local to me and they do exceptional work.  
I might have gone Power Flow, but I’m still running a generator.  I would have had to do an alternator conversion to make it fit.   

I would've gone ahead and used this as an excuse to do the alternator. I just finished the upgrade and can't express how nice it is to see 14.1V at idle.

Sent from my Pixel 6a using Tapatalk

[PT20J]

Here's what my flame tubes look like 400 hours after the muffler was rebuilt

[carusoam]

Great pics!   

Flame tubes that look wicked scary!

Happy Halloween…!

Keep in mind… flame tubes are supposed to keep flame temps from contacting the outer surface of the muffler…

When the tubes mis-direct the hot gasses… the muffler welds are at risk of failing… becoming a CO problem feeding the heater muff.

 

I have no idea what happens if the flame tubes are missing… I think they may have escaped my M20C’s muffler…. 
 

Best regards,

-a-

[Sixstring2k]

23 hours ago, PT20J said:

Here's what my flame tubes look like 400 hours after the muffler was rebuilt

Wait this is only after ONLY 400 Hours after rebuild???? I am sorry sir but what kind rebuild was that? I mean they are mostly gone!

 

[Jsno]

Is that 400 hours after the muffler was rebuilt?  

 

[PT20J]

2 hours ago, Jsno said:

Is that 400 hours after the muffler was rebuilt?  

 

Yes. My IA tells me that the flame tubes are mostly gone in most mufflers he sees. Guess they don’t last long. He’s never seen it cause a problem in Lycomings, but he’s seen it cause a loping idle in big bore Continentals maybe because of uneven back pressure.

[Ragsf15e]

2 hours ago, PT20J said:

Yes. My IA tells me that the flame tubes are mostly gone in most mufflers he sees. Guess they don’t last long. He’s never seen it cause a problem in Lycomings, but he’s seen it cause a loping idle in big bore Continentals maybe because of uneven back pressure.

Mine is much older and they are mostly gone.  My IA said something similar to yours, so I haven’t worried about it.

[EricJ]

My flame tubes as per my borescope a few years ago.    The inspection criteria is just that there aren't pieces of decaying flame tube blocking the exhaust exit.   This passes. 

[Jsno]

Cessna has a SB to remove them due to possibly breaking loose and clogging the muffler.  I pulled my exhaust during o/h and after 900 hours they are intact.  There are plenty of articles about why they are there so I won't go into that.  I would suggest having the muffler pressure checked for leaks.  I'm getting a whole new system from Knisely.