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FAA ACS on Turbo V-Band couplings


DVA

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3 hours ago, thinwing said:

These clamps are the reason I do every oil change at 25/30 hrs ..it's a mini annual every time and every slip joint gets painted with mouse milk including these turbo vclamps.Also the wastegate pivot shaft gets it and checked for freedom of movement.All exaust risers/stubs get checked for blowby than every flight its check that aft exaust connection ....

A writeup with pictures would be great for M20M owners and might just save someone's life.

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  • 1 year later...
On ‎1‎/‎8‎/‎2017 at 4:26 AM, N201MKTurbo said:

I just looked on line and clamps for RaJay turbos are available from the racing world for $23. They look identical... Oh well....

We've used some of those exact clamps in a drag racing application on a twin turbo small blocks that made over 1500hp running over 40lbs of boost.  Installed and removed those same clamps literally dozens of times and never a failure. Granted our runs were 4-6 seconds plus engine warmup/cool down thermal cycles for every pass but I cant imagine they're THAT much different than our blessed $350 aviation versions. 

I'm doing an annual with some upgrades in March and I will definitely be checking my K model clamps now. Thank you for the heads up !

 

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  • 2 months later...
18 hours ago, slowflyin said:

Can anyone verify the part # for the gasket?   My service manual indicates 78084 but it doesn't look like the one pictured in the SB.

Found it- 75845, 78084

So you're the one that bought N64HK. Congratulations! What all are you doing to it?

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Thanks!   The usual new to me AC path.   Working through a small squawk list.     Evaluating the engine health-More bore scoping, regular oil analysis......  That's the reason for the part number questions.  I can't determine from the logs how old, or how many times these v band clamps have been torqued.    Replacing all three for safety's  sake.  Only substantial, immediate upgrade will be a JPI 900.  It goes in next month.  

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On 4/12/2018 at 10:53 AM, slowflyin said:

Thanks!   The usual new to me AC path.   Working through a small squawk list.     Evaluating the engine health-More bore scoping, regular oil analysis......  That's the reason for the part number questions.  I can't determine from the logs how old, or how many times these v band clamps have been torqued.    Replacing all three for safety's  sake.  Only substantial, immediate upgrade will be a JPI 900.  It goes in next month.  

There needs to be one place on this forum that is devoted saving each other money. 

The exhaust V-Band clamp part number  is Lycoming 40D23255-340M which sells for $1060 (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 (see picture below). 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 $539 at Aircraft Spruce (http://www.aircraftspruce.com/catalog/eppages/engineclamps.php). LASAR has it for $544 (https://lasar.com/product/turbo-v-band-clamp-nh1009399-10/)

 

5a851cc9855f9_Vbandturboclamp.jpg.13d3a021831d6577aaf27a763bb29215.jpg

Some shops are buying the Aeroquip clamp and selling it for the Lycoming price. 

$500 here and $500 there adds up.

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My parts manual does not elaborate. Is there a gasket between the tailpipe and turbo exhaust that the above referenced clamp secures?   The above mentioned SB clearly states the gasket always needs replacing.    Any help will be greatly appreciated.

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I have the TCM TSIO-360-SB and last month my exhaust gasket blew resulting in a loss of MAP. Resolved that issue and in that realized my VBand clamp was not safety wired and found a slip joint leaking so my plane is at DMaxwell’s getting exhaust IRAN’d at this moment. I am sure I will have a new clamp as part of the IRAN but am interested (and scared- $$$) to see the parts list but I will feel safer knowing the exhaust will be less likely to kill me.

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  • 3 years later...

Great discussion from the archives.  
 

Does anyone know the expected life of M20K turbo clamps?  I purchased N57055 Jan 2021 and it is currently in annual.  The torbo clamps were discolored and micro cracks observed. $400 bucks each.

B542E0AB-49B5-4432-B25E-81315C3F5D38.jpeg

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1 hour ago, shoyt said:

Great discussion from the archives.  
 

Does anyone know the expected life of M20K turbo clamps?  I purchased N57055 Jan 2021 and it is currently in annual.  The torbo clamps were discolored and micro cracks observed. $400 bucks each.

B542E0AB-49B5-4432-B25E-81315C3F5D38.jpeg

Where are the cracks?

I have those on my plane. But it is not a 231. They will always be discolored, they operate at TIT temperatures.

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I believe...

Those are called V-band clamps.

They are expensive.

They can have single use limitations to them.

Be extra careful about their limitations.... (please look them up, don’t guess)

Re-used V-bands in some applications have failed to maintain clamping force... then allow exhaust leaks...

Unfortunately, exhaust leaks between the exhaust valve and the turbo are extra serious... high pressure, high temperature, random blow torch affect....

Kind of a public service announcement... by a PP, not a mechanic...

Now back to the previously scheduled program... :)

Best regards,

-a-

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  • 1 month later...

Turbo flyers: do yourself a favor and replace the V band clamps rather than reuse. My turbo was overhauled not long ago. The genius that reinstalled it used the 40 year old v band clamps that had been re-torqued countless times. Right on schedule, one v band clamp failed at the spot weld soon afterward. Had it not been for safety wire, I’d be a crispy critter.

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On 1/28/2018 at 1:21 PM, TargetDriver said:

We've used some of those exact clamps in a drag racing application on a twin turbo small blocks that made over 1500hp running over 40lbs of boost.  Installed and removed those same clamps literally dozens of times and never a failure. Granted our runs were 4-6 seconds plus engine warmup/cool down thermal cycles for every pass but I cant imagine they're THAT much different than our blessed $350 aviation versions. 

I'm doing an annual with some upgrades in March and I will definitely be checking my K model clamps now. Thank you for the heads up !

 

The drag racing version only has to last 6 seconds. The aviation version is expected to go 2000 hours....

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