AlexLev Posted March 15, 2019 Report Posted March 15, 2019 Well --- ladies and gentleman, I just had a frustrating day at the shop: most recently I noticed a slight PPM of carbon monoxide in the cabin with the heater on. In cruise flight, it would stay under 10PPM with the heat on. I made a thread about it here: I was in the shop and decided to leak test the muffler. We found a very small crack: It was about 2pm at this point and I asked my mechanic this could be fixed easily and he said he could probably weld it and took the exhaust off. Well, a few minutes into the welding, holes started to form. We tried to fix them and ended up spending 3 hours chasing ever larger leaks. We almost gave up, but decided to try one more hail mary: Here is where we gave up after about 3 hours of welding and testing, repeating, taking the metal off, putting new on, etc: Well now, my muffler is definitely unairworthy and I need a new one. The rest of the stacks look good, but where the hell can I get a muffler. Apparently it's not that easy...any leads/advice? I called Knisley but they can only sell me their system, Acorn welding wanted $1600 to potentially weld the exhaust. I'm not sure if anyone else has any suggestions? Bummer, I was planning to fly the Mooney to Providence tomorrow too. Not sure what the lesson here is (don't try to chase a small crack? or maybe this is a blessing in disguise), but either way, next time your mechanic wants to weld your muffler: SAY NO! Quote
David_H Posted March 15, 2019 Report Posted March 15, 2019 (edited) Is it possible to take the muffler to someone that's good with a TIG welder? I could be wrong, but judging from the pictures, that repair didn't look like it was ever going to come out very well with that patch and lack of surface prep. Edited March 15, 2019 by David_H Quote
RLCarter Posted March 15, 2019 Report Posted March 15, 2019 Heli-Arc (TIG) is where it's at when it comes to thin material. I thought exhaust were a SS alloy, it still might be repairable but it would have been easier before the 1st attemp Quote
lamont337 Posted March 15, 2019 Report Posted March 15, 2019 https://awi-ami.com/ These guys did mine last annual. If I remember correctly we also had to send the 4 stacks so they cloud line everything up on the jig properly. Not sure about the tail pipe though. 1 Quote
Guest Posted March 16, 2019 Report Posted March 16, 2019 Count yourself lucky that the Sensorcon alerted you to the problem. AWI would be a good recommendation for a repair. Or the Kinsey system. Clarence Quote
Prior owner Posted March 16, 2019 Report Posted March 16, 2019 (edited) It is widely recommended to never attempt exhaust system repairs at the shop, and this is also taught in A&P school. Not very cool that they attempted and now it may no longer be repairable... Yes, send it to a repair station that specializes in exhaust repair... if they say not repairable, maybe Alan (Grim Reaper) can help with a replacement? Edited March 16, 2019 by PilotCoyote 1 Quote
tangogawd Posted March 16, 2019 Report Posted March 16, 2019 AWI worked well for me. they will need the risers as well. My shop will weld exhaust routinely, but at a certain point the wall is so thin it will blow through next to the weld. which was happening to mine. I was doing a weld repair every oil change....... finally I got tired of that! $2k and AWI made new everything. And It fell right into place. Quote
cctsurf Posted March 16, 2019 Report Posted March 16, 2019 (edited) Don't despair of having it repaired. My understanding is that they can "repair" almost anything for exhaust (talk to the aftermarket turbo guys on that one). As long as they use one part of the original system it is considered a "rebuilt" system. WAY cheaper than a new one. But then again, there's always the powerflow... <Cracks open can of worms, steps back to watch> Edited March 16, 2019 by cctsurf 1 Quote
Bob_Belville Posted March 16, 2019 Report Posted March 16, 2019 18 minutes ago, cctsurf said: But then again, there's always the powerflow... <Cracks open can of worms, steps back to watch> Now you're talking! 1 Quote
AlexLev Posted March 16, 2019 Author Report Posted March 16, 2019 (edited) Approx how much was the AWI repair? I wonder if buying this on eBay is a bad idea: https://www.ebay.com/itm/Mooney-M20-Muffler-Slip-Rib-Assy-630105-501-Ball-Joint-Style-1218-253/143082553385?hash=item2150628029:g:FB4AAOSwJaxcHAf7 - looks to be what I need. Edited March 16, 2019 by AlexLev Quote
MIm20c Posted March 16, 2019 Report Posted March 16, 2019 (edited) 17 minutes ago, AlexLev said: Approx how much was the AWI repair? 2 hours ago, tangogawd said: ..... finally I got tired of that! $2k and AWI made new everything. And It fell right into place. For just the muffler I’d guess 700-850 especially when you add shipping both ways. From what I see in the pictures it looks more like a complete rebuild of the muffler vs a patch job. However, also understand there is a chance if you send the complete system other parts might be really thin in areas... Edited March 16, 2019 by MIm20c 1 Quote
Guest Posted March 16, 2019 Report Posted March 16, 2019 2 hours ago, cctsurf said: Don't despair of having it repaired. My understanding is that they can "repair" almost anything for exhaust (talk to the aftermarket turbo guys on that one). As long as they use one part of the original system it is considered a "rebuilt" system. WAY cheaper than a new one. But then again, there's always the powerflow... <Cracks open can of worms, steps back to watch> AWI told me to send them a tailpipe flange and they can “repair” the rest from that one part. Clarence Quote
AlexLev Posted March 16, 2019 Author Report Posted March 16, 2019 (edited) Anyone know part # for this muffler? The parts manual for the M20G says 630060-001: However, this site below says M20G is 630105-501 (which is also what that eBay listing above says), so I am not entirely sure: https://www.aviall.com/medias/0464.pdf?context=bWFzdGVyfHBkZnwxMDEwMzg5fGFwcGxpY2F0aW9uL3BkZnxwZGYvaDZiL2gzYi84ODE0MDgzNDQwNjcwLnBkZnwyYWM2MzQ3NGMyOTA0YWNhY2E5NmU4YTk5Mjc0M2U0NzViZGQxMjgyMzhiNmU2N2MwMDFhNTE1MmIzNTcwNzBl&attachment=true (ah, at a closer look it looks like serial #'s 69000 and above for the M20G might be -501, while mine is still in the 68000s, so I am probably -001). I wonder if AMI may have it in stock: https://awi-ami.com/mooney-180-ball-rib-muffler-630060-001.html - will try to call them on Monday. Edited March 16, 2019 by AlexLev Quote
carusoam Posted March 16, 2019 Report Posted March 16, 2019 See if the doc is around... @M20Doc to clear up the part number /muffler detail... Best regards, -a- Quote
Guest Posted March 16, 2019 Report Posted March 16, 2019 (edited) This might help. Note 2 drives you to the -501 muffler. Edited March 16, 2019 by M20Doc Quote
AlexLev Posted March 16, 2019 Author Report Posted March 16, 2019 3 hours ago, M20Doc said: This might help. Note 2 drives you to the -501 muffler. Thanks, I think mine would still be the -001 since if I'm interpreting note 2 correctly, it's saying aircraft after serial # 69000 get the -005 replacement. Quote
Yetti Posted March 16, 2019 Report Posted March 16, 2019 I can't weld, but whoever was trying to weld yours, can't weld either. Looks like too much heat and wrong size rod/wire 1 Quote
AlexLev Posted March 16, 2019 Author Report Posted March 16, 2019 5 minutes ago, Yetti said: I can't weld, but whoever was trying to weld yours, can't weld either. Looks like too much heat and wrong size rod/wire Yeah, at first he was using a thin piece of metal and that large piece of sheetmetal was more of a hail mary after 3-4 attempts of welding/testing for leaks, etc, but he burned a few holes claiming the exhaust was already really thin and in bad shape, but he could have just been using too much heat. Honestly, the initial crack was so tiny and I had such a small leak a little bit of JB Weld might have done the trick at least for a little while. Quote
lamont337 Posted March 16, 2019 Report Posted March 16, 2019 11 hours ago, MIm20c said: However, also understand there is a chance if you send the complete system other parts might be really thin in areas... All the more reason to have it looked at. Quote
N6018Q Posted March 16, 2019 Report Posted March 16, 2019 16 hours ago, RLCarter said: Heli-Arc (TIG) is where it's at when it comes to thin material. I thought exhaust were a SS alloy, it still might be repairable but it would have been easier before the 1st attemp 16 hours ago, David_H said: Is it possible to take the muffler to someone that's good with a TIG welder? I could be wrong, but judging from the pictures, that repair didn't look like it was ever going to come out very well with that patch and lack of surface prep. 8 minutes ago, Yetti said: I can't weld, but whoever was trying to weld yours, can't weld either. Looks like too much heat and wrong size rod/wire I've worked in the metal trade around welders my entire adult life and not even the best of them would recommend repairing that thin metal without TIG or MIG. Yes, there are shops/welders out there that would be able to repair, even in its current state. 1 Quote
Guest Posted March 16, 2019 Report Posted March 16, 2019 1 hour ago, AlexLev said: Thanks, I think mine would still be the -001 since if I'm interpreting note 2 correctly, it's saying aircraft after serial # 69000 get the -005 replacement. I would interpret it as used on the serial numbers per note 2 and as replacement for earlier serial numbers. Clarence Quote
carusoam Posted March 16, 2019 Report Posted March 16, 2019 Welding or gluing.... Exhaust system metal might be made from some high end metals... like Inconel.... probably adds to the challenge of welding properly... Either way, in the past... small cracks have turned into long tears in a single flight... small amounts of CO, turned into too much CO... Often, CO is not detectable by the person being poisoned... So... even if JB weld could block the hole, it won’t be able to stop a crack from propagating... it doesn’t have the strength or adhesion to do so... Compare the costs... a proper fix. broken plane, still needing a proper muffler fix. Either way, the cost seems to have been incurred already. Next steps seem to be getting the muffler OH’d at the lowest cost... typical muffler OHs are done by a couple of exhaust welding shops... the procedure is two step... replace the front half parts... then... replace the back half parts... It looks totally brand new when they are done. Working with ancient sheet metal that is in a hot environment can have a lot of wear...over 50years... flame tubes typically break down first, and the hottest spots move to places that aren’t built to be that heat resistant... If you can’t find the flame tubes, they may have departed the plane already... If able... or when able... get a new muffler, or a muffler OH... At the point you have measured an increase of CO related to the heater... it has become time to enact plan B... stop playing with Fire, er CO.... This is sample logic that can be used to free up the necessary funds to improve the safety level of one’s Mooney... PP thoughts only, not a mechanic... Best regards, -a- 2 1 Quote
Brian_tii Posted March 17, 2019 Report Posted March 17, 2019 Could also try Dawley Avaition. They rebuilt our exhaust last year including some material upgrades (inconnel flame cones) to hopefully make it last longer. Price was reasonable. 1 Quote
MinneMooney Posted March 17, 2019 Report Posted March 17, 2019 Dailey Aviation rebuilt the system on my ‘65C before I purchased it. It looks like new. Quote
AlexLev Posted March 18, 2019 Author Report Posted March 18, 2019 After calling both Dawley and AWI-AMI, I went with AWI-AMI for them to overhaul the muffler. I also looked into www.wagaero.com, they had the best price but they don't remanufacture them it seems, just repair. 1 Quote
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