Turbo v clamp

[AeroEng]

Hey everybody, throwing a question out for the brain trust.

I’m planning to replace the right turbo on my 07 Acclaim (it’s at 900 hours and showing signs of breakdown). I was planning to also replace the v-band clamp (part 657198) leading to the exhaust. Everything I’ve read indicates that you can use it again, but I was going to be extra cautious and just get a brand new one.

After hunting for a while, I have been unable to find a single new clamp available online. Lead-times appear to be in the HUNDREDS of days…

Should I feel comfortable reusing the existing clamp already on the turbo (and just checking it at oil changes and replacing as soon as the new clamps become available)?  Or should I not replace the turbo for fear that retorquing the v-clamp will cause damage and potential total failure of the clamp?

Also - anyone know where I can get a darn clamp?!  Seems ridiculous that we can’t get these parts…

Thanks as always. Your help is greatly appreciated. 

Richard 

Edited February 15, 2022 by AeroEng

[Davidv]

2 hours ago, AeroEng said:

Hey everybody, throwing a question out for the brain trust.

I’m planning to replace the right turbo on my 07 Acclaim (it’s at 900 hours and showing signs of breakdown). I was planning to also replace the v-band clamp (part 657198) leading to the exhaust. Everything I’ve read indicates that you can use it again, but I was going to be extra cautious and just get a brand new one.

After hunting for a while, I have been unable to find a single new clamp available online. Lead-times appear to be in the HUNDREDS of days…

Should I feel comfortable reusing the existing clamp already on the turbo (and just checking it at oil changes and replacing as soon as the new clamps become available)?  Or should I not replace the turbo for fear that retorquing the v-clamp will cause damage and potential total failure of the clamp?

Also - anyone know where I can get a darn clamp?!  Seems ridiculous that we can’t get these parts…

Thanks as always. Your help is greatly appreciated. 

Richard 

I had a different engine, but when we replaced the turbo transition on my Bravo we reused the existing clamps.  My mechanic (who only works on Mooneys) inspected the clamps for any wear and put them back.  300 hours later and didn't have any issues.

[Guest]

General rule of thumb is replacement after the second removal.

Clarence

[LANCECASPER]

7 hours ago, Davidv said:

I had a different engine, but when we replaced the turbo transition on my Bravo we reused the existing clamps.  My mechanic (who only works on Mooneys) inspected the clamps for any wear and put them back.  300 hours later and didn't have any issues.

http://mooney.free.fr/Mooney SB SI/283a.pdf     The original V clamps were only spotwelded and should have been replaced within 10 hours of the service bulletin. On the riveted ones you were limited to two re-torques. Those original v-clamps giving out were responsible for at least a couple fires and deaths on Bravos.

 

On the Bravos regarding pricing for the clamps:

The exhaust V-Band clamp part number  is Lycoming 40D23255-340M which sells for over $1200 (http://www.aircraftspruce.com/catalog/eppages/lycomingcouplings.php) 

However the Mooney service bulletin (http://mooney.free.fr/Mooney SB SI/283a.pdf)  says that the equivalent Aeroquip part number NH1009399-10 can be used. Aeroquip makes the above part for Lycoming - they are the exact same part. Lycoming names them as their vendor on this part on this service instruction: https://www.lycoming.com/sites/default/files/Assembly and Torque Procedures for V-Band Couplings.pdf).

The Aeroquip part is a lot less at Aircraft Spruce (http://www.aircraftspruce.com/catalog/eppages/engineclamps.php). 

 

@AeroEng regarding the clamps for the Acclaim let's see if we can find out who makes it.

The service bulletin does say to replace it (https://www.mooney.com/wp-content/uploads/2020/12/SBM20-299A.pdf) but doesn't mention anything about how many re-torques are allowed.

[carusoam]

Richard be extra sure you get a solid answer for your situation…

A V-band failure at altitude can lead to a cutting torch operating under the cowling… without it saying anything….

Some people are unaware of the issues involved…

The cost of V-bands makes them easy to want to keep…

The sturdy look of the V-bands makes them easy to want to keep…

Having seen the affect of the cutting torch under the cowl makes them easy to toss out….  
 

Doc above has seen a few Acclaims…

Another reference might be found by calling Continental directly…

It would be nice if there were a way to check the health of the V-bands.  Camera, Visual inspection, CO monitoring…

PP thoughts only, not a mechanic…

Best regards,

-a-
 

 

 

[AeroEng]

Thanks very much for the thoughtful comments. My default would be to replace it, but they are nowhere to be found!

I will give Continental a call. Maybe they will share information about their source and provide an alternative part number.  If I come across that info, I will certainly share it here. 

-R
 

 

[LANCECASPER]

1 hour ago, AeroEng said:

Thanks very much for the thoughtful comments. My default would be to replace it, but they are nowhere to be found!

I will give Continental a call. Maybe they will share information about their source and provide an alternative part number.  If I come across that info, I will certainly share it here. 

-R
 

 

I would think if it hasn't been off before and it's safety-wired properly it shouldn't pose any risks. Every time it was re-torqued on the Bravo (maximum twice before replacement)  it was supposed to be noted in the logs. 

[haymak3r]

Holy crap. The prices of these things just blow my mind. They are just v-band clamps! Hell, I picked up some 3" ones for my turbo project rig years ago from a local truck stop of all places for like 20 bucks a piece! They routinely were subjected to very high heat and sometimes were "possibly" red with the turbine housing, downpipe... Never once did I ever think about needing to replace it, nor did they ever leak. Sometimes, I swear these companies just charge whatever the hell they want because AVIATION... Are they made from some exotic material? I know I am not providing anything here(and apologzie for that), but dang, those links just made my blood boil. 

 

Is it just because of how fast they can potentially get cooled down?

[LANCECASPER]

31 minutes ago, haymak3r said:

Holy crap. The prices of these things just blow my mind. They are just v-band clamps! Hell, I picked up some 3" ones for my turbo project rig years ago from a local truck stop of all places for like 20 bucks a piece! They routinely were subjected to very high heat and sometimes were "possibly" red with the turbine housing, downpipe... Never once did I ever think about needing to replace it, nor did they ever leak. Sometimes, I swear these companies just charge whatever the hell they want because AVIATION... Are they made from some exotic material? I know I am not providing anything here(and apologzie for that), but dang, those links just made my blood boil. 

 

Is it just because of how fast they can potentially get cooled down?

The original ones on the TLS (later Bravo) were just spotwelded together. Combine that with people running their TIT to 1750 degrees and you have a recipe for disaster. When airplanes burned and people died I'm sure the company that made the clamp got sued big time. I'm actually surprised that any company (Aeroquip) is willing to make these at any price knowing that they are going on an airplane and knowing the history of Bravos and Mirages (and probably others) that have caught fire. The new ones are heavier gauge and are riveted and I'm not aware of any failures, but one failure wipes out all the profit you made and a lot more. Mooney designed a heat shield that was to be installed on all M20M's at the same time that the clamp was to be replaced with the better design. With exhaust gasses pointed right at the firewall and the pilot I don't think the heat shield gave you a lot more protection but every second counts.

[haymak3r]

ugh. It just blows my mind. I get it that they have to try and recuperate their costs because somehow they are at fault.. It just sucks to see things so outrageous. 

[thinwing]

i replaced mine at 3rd removal when replacng waste gate...mechanic thought it was unnecessary but i insisted ,,and he had the riveted clamps in stock at his shop because he maintains a lot of turbo charged aircraft...mine are also double safetied in place with really stout stainless safety wire and i check those clamps and all exaust slip joints every 25 hrs at oil changes.The stainless heat shield was mandated by AD to address heat damage to nearby brake lines I believe...its very thin material and I dont think it would standup to a 1600 degree blow torch.

[Guest]

It might be worth checking with Tornado Alley Turbo or Ram Aircraft to see what they have.  Ram makes loads of PMA parts.

Clarence

[AeroEng]

I agree with @haymak3r  the prices are insane. You’d think they were made out of diamond. 
 

I called continental and was told there is only a 9 day lead time. That’s different than the 250 days I was given by Air Power. I placed an order. Here’s hoping it will ship closer to 9 days from now…

I suspect the clamp would be just fine without replacement, but given the catastrophic nature of the potential failure, I figure I might as well replace with new.  
 

Thanks to everyone for the helpful comments. Great group of people on here!

-R

[Richie the C]

My V band clamp broke at the spot weld the very next flight after turbo R&R.  Had it not been safety-wired, I wouldn’t be writing this. These things are not to be trifled with. Note: I went back to naturally aspirated shortly after that.

[carusoam]

Nice vband pirep Richie!

Thanks for sharing your experience.

Best regards,

-a-

[AeroEng]

Scary experience for sure. I will be checking mine religiously until the new one comes in…. Glad the safety wire did it’s job. 

R

[AeroEng]

Just a quick update to let everyone know that my new v-band clamp shipped today. About a two week wait—not too bad. Sharing so people know these parts are available. Don’t listen to the downstream supplier when they give you a 200 day lead time. Continental cranks then out regularly. 
 

Thanks again for all the help. Safe flying everybody. 

[LANCECASPER]

21 hours ago, AeroEng said:

Just a quick update to let everyone know that my new v-band clamp shipped today. About a two week wait—not too bad. Sharing so people know these parts are available. Don’t listen to the downstream supplier when they give you a 200 day lead time. Continental cranks then out regularly. 
 

Thanks again for all the help. Safe flying everybody. 

Would you mind sharing the price?

[carusoam]

Great follow-up R!

It is a too important piece of hardware to be a long lead time device….

Best regards,

-a-

[smwash02]

Looks like there's an AD in the works for these failing. Here is the FAA article on it.

[N201MKTurbo]

24 minutes ago, smwash02 said:

Looks like there's an AD in the works for these failing. Here is the FAA article on it.

I just read that. It looks like I will be buying a new clamp sometime soon.

Did you notice in the cost estimate, it didn't include the price of the clamp!

[N201MKTurbo]

My friend with the twin Comanche is screwed, He has to buy two!

Fun Fact:

There are only 24 airworthy turbo Comanches in the world. 4 of them live at KCHD.

[smwash02]

2 minutes ago, N201MKTurbo said:

I just read that. It looks like I will be buying a new clamp sometime soon.

Did you notice in the cost estimate, it didn't include the price of the clamp!

Yeah, I'm going to also try to get ahead of the curve and pick up one.

I also noticed it left out the price -- perhaps because they're making a blanket statement 'all turbos'? The price will likely be different across the various models of clamps for the various manufacturers.

[kortopates]

yep, the AD will require following the FAA Best practices guide for turbo exhaust components. Which generally calls for replacing after 500 hrs in service or on condition earlier following annual inspection criteria. There are many
more details i am not including.
But highly recommend reviewing all the photos of failed v-bands. The crazy thing is the photos showed failed clamps showing signs of corrosion and likely exhaust leak damage; i.e. signs begging for them to not only be replaced but probably also addressing exhaust component issues too. No surprise they failed. My take away: Keep up on exhaust component maintenance and you probably won’t get any surprises with failing v-band clamps.


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[carusoam]

Just got the email…

it is a request for input first…

So…

if you have any input… now would be the time…

looks like they are leaning towards 500hr replacement…

how many hours are we getting before being replaced for other reasons?

-a-