M20E Tailpipe Ball Joint + Clamp Torque

[TheAv8r]

We're installing a new tailpipe and a new Mooney clamp on my bird and I have been hunting all over trying to find the correct torque values. My A&P warned me that if it's too tight, the metal won't be able to expand as it heats and flex enough and could break, but it also doesn't need to be too loose otherwise it could leak or the tailpipe bang into the airframe. Which means we need to find the right torque to use vs. guessing. But it's not in the Mooney Service Manual, Lycoming Manual, or any other manual I can find, so asking the Mooney Braintrust here . 

There's a ball & socket joint with AN bolts and springs where it connects to the other parts of the exhaust, what torque do you apply to the bolts to give the springs enough springiness but not too much? Tailpipe is 630056-501 (OG) replaced with PMA A630119-501

The clamp hangar is P/N 630041-501 and it connects to the rubber shown in the diagram below with an AN3 bolt that we're not sure of what the torque needs to be either.

[A64Pilot]

No experience with a Mooney, but on other aircraft there is no torque, you tighten until it’s not rattle loose but loose enough until it can easily move, on those aircraft it snugs up right after starting from heat.

If nothing else this bumps the thread to the top.

[TheAv8r]

9 minutes ago, A64Pilot said:

No experience with a Mooney, but on other aircraft there is no torque, you tighten until it’s not rattle loose but loose enough until it can easily move, on those aircraft it snugs up right after starting from heat.

If nothing else this bumps the thread to the top.

Yeah, that's about where we have it and the same way we approached it... we figured as long as it can move on all planes in the ball joint it's good. The clamp's been a bit harder.

[A64Pilot]

I’ve seen some put anti-seize on it, I never did but don’t see how it would hurt.

[Fly Boomer]

1 hour ago, TheAv8r said:

so asking the Mooney Braintrust here

Not familiar with your ball clamp, but we used some of this on slip joints recently.  I'll know how well it works in about a year.
https://www.mcfarlaneaviation.com/products/category/dam-exhaust-lube/

[PT20J]

The ball joints are supposed to be fastened with AN3-16 bolts, washers, castle nuts, cotter pins and coil springs per the IPC. The springs hold the tension correctly. There is no torque since the bolt length is fixed and the nut is retained by the cotter pin. If the joint is too loose, it's because the springs have lost tension and should be replaced. The torque on the hanger isn't critical but if you really want to torque the bolts, just use the standard torque for each bolt size.

[47U]

4 hours ago, TheAv8r said:

There's a ball & socket joint with AN bolts and springs where it connects to the other parts of the exhaust, what torque do you apply to the bolts to give the springs enough springiness but not too much?

I plagiarized this pic from PowerFlow.  Therefore the specified dimension might not be the correct for your ball joint, but you can get the idea.  Don’t smoke the AN3 bolts down so far as to fully compress the springs, just enough that’s it’s secure, but still can adjust under vibration.  (Like Skip said.)

[TheAv8r]

Thanks gents, we did indeed use AN3-16 bolts + hardware and it was tightened until the hole in the thread lined up with the castle nut to put the cotter pin in, so it looks like everything is lined up like it's supposed to be. There is give in the springs so it can move. We will move forward as-is then!

[PT20J]

18 hours ago, 47U said:

I plagiarized this pic from PowerFlow.  Therefore the specified dimension might not be the correct for your ball joint, but you can get the idea.  Don’t smoke the AN3 bolts down so far as to fully compress the springs, just enough that’s it’s secure, but still can adjust under vibration.  (Like Skip said.)

The cotter pin is way too long.

[EricJ]

17 minutes ago, PT20J said:

The cotter pin is way too long.

Definitely not trimmed per AC 43.13. 

[N201MKTurbo]

Not an airworthiness issue, but it will try to let the blood out of the next guy who works on the engine.

[TheAv8r]

On 6/19/2024 at 9:12 AM, N201MKTurbo said:

Not an airworthiness issue, but it will try to let the blood out of the next guy who works on the engine.

After rigging the cowl flaps and putting the airbox bolts on it, I can assure you, trimmed cotter pins or not, blood will be had!