Exhaust repair shops, post Hartzell?

[Immelman]

Does anyone have a shop that will repair one of our mufflers?

66 M20E with the (original) exhaust system that joins the pieces together with bolts and springs. At annual we discovered one of the 3 bolt holes on one of the muffler flanges has broken.

Previously we used Knisley Welding in CA who did great work for a reasonable cost. My IA told me that they were acquired by Hartzell..... as have been a number of shops, and that they apparently no longer do Mooney work, I have not yet confirmed this personally. Hartzell had previously acquired several other aviation welders... consolidation.

The word I received was that under this Hartzell umbrella, the Mooney work was to be done by "Acorn" in Canada. Calls to Acorn to arrange for shipping the muffler go un-answered...

I have thought about the power flow, and don't think a whole new system is worth the money.

Any ideas of how to get this repaired? Or rebuilt?

 

[47U]

14 hours ago, Immelman said:

Previously we used Knisley Welding in CA who did great work for a reasonable cost. My IA told me that they were acquired by Hartzell.

Your IA might have incorrect information.  I called Knisley a few weeks ago to inquire about a modification to my muffler shroud.  A person who works for AWI in Minneapolis answered the phone.  He was attentive to my questions.  If you call the old Knisley phone number, your call should be forwarded to AWI.  I can PM you an email address to the AWI rep I talked to, if you wish.  

Knisley - (800) 522-6990

AWI - (800) 597-4315

Edit:  Sooooooo… AWI is a subsidiary of Hartzell.  Learn something new everyday (I hope).  Thanks Rich! 

Edited March 26, 2024 by 47U
Clarification

[TheAv8r]

I just used AWI for my exhaust overhaul and though we haven't installed it yet, the work seems quality. They have a good reputation and were great at communicating.

[N201MKTurbo]

[Immelman]

Thank you!

I’ve got a call into AWI hoping they can provide a reasonable repair quote. Or OH if needed.

[Immelman]

An update: AWI in Minnesota quoted a reasonable repair estimate, and a reasonable cost for total overhaul, in case the muffler was not repairable. We are sending the system to them today.

Part of my confusion here was that the person at my FBO doing the annual who made contact with AWI seemed like they got a confusing set of directions about whether AWI in Minnesota would repair it, or it had to be sent to Acorn in Canada....

[Igor_U]

AWI did a great work on my exhaust couple years ago when I put the "new" engine on my plane. I actually sent the exhaust to Dawley that I used in the past but Hartzell parent Co. acquired it and closed the duplicated facility. Dawley phone # was still working so I suspect the same is happening with Knisley Welding.

As for pricing: it was definitely somewhat higher then I used to pay at Dawley but not excessive at the time. But with disappearance of smaller shops I can see pricing getting higher due to lack of competition.

 

 

[tim417]

On 3/28/2024 at 9:05 AM, Immelman said:

An update: AWI in Minnesota quoted a reasonable repair estimate, and a reasonable cost for total overhaul, in case the muffler was not repairable. We are sending the system to them today.

Part of my confusion here was that the person at my FBO doing the annual who made contact with AWI seemed like they got a confusing set of directions about whether AWI in Minnesota would repair it, or it had to be sent to Acorn in Canada....

It looks like I may be in need of a muffler repair or OH for my 63 M20C. It’s only 8 years old but the flame tubes are already deformed. Did AWI give an ETA for the repair time?

 

Tim

[Immelman]

15 hours ago, tim417 said:

It looks like I may be in need of a muffler repair or OH for my 63 M20C. It’s only 8 years old but the flame tubes are already deformed. Did AWI give an ETA for the repair time?

 

Tim

3-5 days. For the repair, can’t speak to an overhaul time. Can’t complain about that! We’ll see how it goes, system is still en route to them.

[tim417]

1 minute ago, Immelman said:

3-5 days. For the repair, can’t speak to an overhaul time. Can’t complain about that! We’ll see how it goes, system is still en route to them.

Oh that isnt bad at all. Keep us posted!

[bcg]

AWI did my exhaust in September when I did my annual. Flame cones were gone, it ended up being $2700 for everything, including shipping, and took right at 3 weeks. I only had an IRAN done but essentially got back an overhauled exhaust because it needed almost everything.

Sent from my Pixel 6a using Tapatalk
 

[tim417]

10 minutes ago, bcg said:

AWI did my exhaust in September when I did my annual. Flame.cones we're gone, it ended up being $2700 for everything, including shipping, and took right at 3 weeks. I only had an IRAN done but essentially got back an overhauled exhaust because it needed almost everything.

Sent from my Pixel 6a using Tapatalk
 

Was that for just the muffler or the entire system? Aviation costs are getting ridiculous….

[bcg]

Just now, tim417 said:

Was that for just the muffler or the entire system? Aviation costs are getting ridiculous….

It was everything.  Muffler, the shroud, down pipes, the whole shebang.  The shroud has a hole in it and they had to do some work on the pipes as well, I can't remember what all.  I was adding a JPI also so, we had them weld up the old EGT probe hole while they had it.

[tim417]

My pipes and shroud look to be in good shape. The whole system is only 8 years old and made by Knisley. Just the flame tubes are AFU. Trying to find an expedient and economically sane fix. 

[bcg]

1 minute ago, tim417 said:

My pipes and shroud look to be in good shape. The whole system is only 8 years old and made by Knisley. Just the flame tubes are AFU. Trying to find an expedient and economically sane fix. 

I don't know that there are really any options other than AWI now.  They told us we had to send them everything so they could inspect it all, I'm not sure if they'll let you send just the muffler if you push back on that.  I had to send the shroud and we needed the EGT probe hole welded anyway, so it wasn't really a big deal to me.  This was an expensive annual but, its over with now and the plane flies great.  It's only money, I can make more...I hope.

[N201MKTurbo]

Any A&P who knows how to weld can do it. It is in 43.13-1B. I’ve done it. You can make a jig from your existing system by just laying the system upside down on a piece of plywood. Mark the position of the flanges and drill mounting holes for the risers. Bolt the system to the plywood. Assemble the new parts on the jig and tack them together, then take them off and run the welds.

I have found it easy around here to find race shops that can make the bends and slip joints. For little money.

I will admit I don’t do the welding. I know guys that are artists with a TIG torch. I get them to run the welds.

[tim417]

2 hours ago, bcg said:

I don't know that there are really any options other than AWI now.  They told us we had to send them everything so they could inspect it all, I'm not sure if they'll let you send just the muffler if you push back on that.  I had to send the shroud and we needed the EGT probe hole welded anyway, so it wasn't really a big deal to me.  This was an expensive annual but, its over with now and the plane flies great.  It's only money, I can make more...I hope.

There are a couple shops that work on aircraft exhausts besides AWI. I will be reaching out on Monday to see what my options are. 

[PT20J]

On 3/29/2024 at 8:45 PM, tim417 said:

It looks like I may be in need of a muffler repair or OH for my 63 M20C. It’s only 8 years old but the flame tubes are already deformed. Did AWI give an ETA for the repair time?

 

Tim

If the only issue is the flame tubes, I would discuss it with your IA before spending a lot to have the muffler repaired. Mine were pretty much gone about 400 hours after a rebuild. My very experienced IA says that he sees that all the time and doesn't consider it an airworthiness issue unless they fail in such a way that blocks the exhaust. Usually small pieces break off and go out the exhaust. Any larger loose pieces that remain inside the muffler should be removed. 

[EricJ]

7 minutes ago, PT20J said:

If the only issue is the flame tubes, I would discuss it with your IA before spending a lot to have the muffler repaired. Mine were pretty much gone about 400 hours after a rebuild. My very experienced IA says that he sees that all the time and doesn't consider it an airworthiness issue unless they fail in such a way that blocks the exhaust. Usually small pieces break off and go out the exhaust. Any larger loose pieces that remain inside the muffler should be removed. 

+1 on that ^^^

I think my exhaust is the original from 1977, and the flame tube has eroded awary entirely.   There's essentially nothing left.    The only inspection criteria for it is that there isn't a chunk blocking the outlet.   Otherwise the only required inspection criteria for the muffler is that it doesn't leak.

My hangar neighbors say my airplane sounds cool, so that's a plus. 

[tim417]

35 minutes ago, PT20J said:

If the only issue is the flame tubes, I would discuss it with your IA before spending a lot to have the muffler repaired. Mine were pretty much gone about 400 hours after a rebuild. My very experienced IA says that he sees that all the time and doesn't consider it an airworthiness issue unless they fail in such a way that blocks the exhaust. Usually small pieces break off and go out the exhaust. Any larger loose pieces that remain inside the muffler should be removed. 

I wouldnt mind if it the tubes were just eroded, but I am concerned about pieces breaking off to block the exhaust. My IA is happy to sign off as airworthy, but Savvy recommends repair or OH of the muffler. How does one tell if it will fail in such a way that it will block the exhaust vs if it will just come out in small pieces?

I am all for saving cash as this has been an expensive annual. But I prefer not to wait until a big piece breaks off and blocks my exhaust while I am in the air  

[PT20J]

If you are worried about it, then it might be worth the money to repair since it will help you sleep better.

I would take the opinion of the local IA because he can see it and the Savvy IAs are only able to look at a photo. Sometimes things look different from different perspectives.

The outlet of the muffler through the ball joint and tail pipe is a pretty large opening -- I can get my hand through it (barely). It's hard to imagine any part of a flame tube being large enough to lodge there. 

[EricJ]

If you have a flexible borescope or a cheapie endoscope, you can run the camera up the exhaust pipe like an airplane proctologist and inspect the muffler outlet and flame tube.   This is how I initially determined that mine was essentially gone.   If you're worried about blockages or the condition of the flame tube or whether it is disintegrating sensibly or there's a big chunk rattling around in there, that's a fairly easy, non-intrusive way to get an idea of what's going on.

Cases of a big chunk blocking the muffler outlet are very rare, but do seem to have happened in the past.

[tim417]

 

2 hours ago, PT20J said:

If you are worried about it, then it might be worth the money to repair since it will help you sleep better.

I would take the opinion of the local IA because he can see it and the Savvy IAs are only able to look at a photo. Sometimes things look different from different perspectives.

The outlet of the muffler through the ball joint and tail pipe is a pretty large opening -- I can get my hand through it (barely). It's hard to imagine any part of a flame tube being large enough to lodge there. 

 

1 hour ago, EricJ said:

If you have a flexible borescope or a cheapie endoscope, you can run the camera up the exhaust pipe like an airplane proctologist and inspect the muffler outlet and flame tube.   This is how I initially determined that mine was essentially gone.   If you're worried about blockages or the condition of the flame tube or whether it is disintegrating sensibly or there's a big chunk rattling around in there, that's a fairly easy, non-intrusive way to get an idea of what's going on.

Cases of a big chunk blocking the muffler outlet are very rare, but do seem to have happened in the past.

These are both good advice. I’ll stick my borescope up the back end and see what’s going on. I will also call around and see exactly what cost and downtime will be as well. 

Tim

[PT20J]

I did a little research. Apparently older Pipers had a muffler design where flame tubes could dislodge and block the exhaust. There is an AD68-05-01. It’s a different design than the M20J though. 

[47U]

17 minutes ago, PT20J said:

It’s a different design than the M20J though. 

I had one of those.  There’s a wire ‘bale’ welded inside the end of the exhaust pipe that goes into the muffler.

 Photo credit to Wag-Aero.