M20F Executive 21 Engine Mount Crack

[Noah Cohen]

My mechanic found a crack in my engine mount on my 1970 M20F Executive 21. Can anyone recommend who to send the mount to for repair? See attached photo. IMG_7207.heicIMG_7207.heic

[Shadrach]

7 hours ago, Noah Cohen said:

My mechanic found a crack in my engine mount on my 1970 M20F Executive 21. Can anyone recommend who to send the mount to for repair? See attached photo. IMG_7207.heicIMG_7207.heic

Hard to get perspective from the picture but it looks like a partially cracked weld joint (it may have been repaired poorly in the past). That can be fixed locally if you can find an A&P with welding experienced. 

[SheryLoewen]

LASAR Parts has done many,

[Noah Cohen]

On 10/30/2021 at 5:46 PM, SheryLoewen said:

LASAR Parts has done many,

Thank you! I will give them a call. From the research my mechanic has done, you have to have a certified repair station to repair the engine frame. 

On 10/30/2021 at 5:42 AM, Shadrach said:

Hard to get perspective from the picture but it looks like a partially cracked weld joint (it may have been repaired poorly in the past). That can be fixed locally if you can find an A&P with welding experienced. 

From what my mechanic says this takes someone that specializes in this because it is not regular steel.....

[thinwing]

isnt it chromemoly?

[Shadrach]

33 minutes ago, thinwing said:

isnt it chromemoly?

Yep, I’m almost positive it’s 4130 Chrome-moly. Nothing exotic. Requires a skilled tig welder. Certainly would be prudent to completey strip and thoroughly inspect the mount.  Having it overhauled by a repair station specializing in engine mounts puts the liability on a specialist. No upside to this kind of work in the eyes of most mechanics.  The actual repair won’t take a lot of time but the perceived liability makes it unattractive. Plus, most mechanics don’t do a lot of welding these days. 

[TTaylor]

LASAR, WagAero, Loree Air, Aerospace Welding Minneapolis, (AWI) are a few.

 

[carusoam]

+1 for sending it out to a shop that does engine mounts…

Do it once, get it done right, no repeats…

The Expense grows if the engine has to come off again…

Not too expensive to have it OH’d… it comes back looking brand new…

PP thoughts only, not a mechanic…

Best regards,

-a-

[EricJ]

On 10/30/2021 at 3:42 AM, Shadrach said:

Hard to get perspective from the picture but it looks like a partially cracked weld joint (it may have been repaired poorly in the past). That can be fixed locally if you can find an A&P with welding experienced. 

Doesn't need to be an A&P, but the work needs to be "supervised" by an A&P, which isn't tightly defined.   It is very common to send work out to general fabrication shops that are competent and install it as supervised work.

[A64Pilot]

6 hours ago, EricJ said:

Doesn't need to be an A&P, but the work needs to be "supervised" by an A&P, which isn't tightly defined.   It is very common to send work out to general fabrication shops that are competent and install it as supervised work.

Exactly, I’m a welder but most A&P’s aren’t, but even then as I do so little welding now I’d take it to a professional who welds every day and have them work under my supervision.

Having said that, many welders won’t weld on aircraft parts as they are afraid of the liability and legality etc. 

I’m 99% sure even Acetelene welding is allowed IAW 43.13,  but TIG is really the way to go.

‘I’m also pretty sure that Mooney has used MIg at times in the past as it’s faster and therefore cheaper than TIG, but TIG is a better weld

Edited November 2, 2021 by A64Pilot

[N201MKTurbo]

I would thoroughly clean And strip that area before pulling the engine. I would hate to do all that work because of a paint chip.

[A64Pilot]

Oh, and I forgot to add, usually only time a repair station is required is when there are bent tubes and or more than one tube needs replacing etc as they often have many jigs for different aircraft and of course the local welder won’t, 

But for welding up a crack you don’t need a Jig, depending on where it is, you may not even have to pull the engine.

‘Yes I’m aware of the possible consequences of welding on a airframe with engine and avionics installed, but I’ve never seen any damage, but it is possible I’m sure.

‘What I have seen is a part being magnetized which screws with the mag compass and the magnetized part has to be de-gaussed,which if you don’t have a great big electric horseshoe magnet can be a pain. But that can happen whether the part is installed or not.

[Shadrach]

18 hours ago, EricJ said:

Doesn't need to be an A&P, but the work needs to be "supervised" by an A&P, which isn't tightly defined.   It is very common to send work out to general fabrication shops that are competent and install it as supervised work.

Yes, I know but in my experience it’s getting harder and harder to find A&Ps that will do or sign off this kind of work.