Potential buying candidate: Wing spar corrosion and engine status

[Martin S.]

Dear everybody,

 

I‘m into the purchase of a m20j. I had an initial look at the bird, and found two points making me nervous.

There is some starting corrosion in the wheel well (see fotos). Is there any chance of better analysing whether this is already serious or not? I inspected the wings with a cam, the rest looked pretty ok to me.

 

The bird was sitting for a while. I borescoped one cylinder. Any alarming signs that come to your mind, when looking at the cylinder and piston?

 

Thanks for your help - Martin

Edited May 11, 2020 by Martin Stolle
typo

[carusoam]

Welcome aboard Martin...

Where is this Mooney currently?

There are three types or places corrosion needs to be found prior to being purchased...

1) Structural... if the part is a thick aluminum bar... and has corrosion on it... this means look further into getting It fixed before purchase...

2) Intergranular corrosion vs. surface corrosion...

3) The wheel wells are where the main spar is... lots of exposure possible for big expensive parts...

4) Cylinder walls... if you can see the nice cross hatching in the surface... this is a good sign the walls are in nice condition... not worn... if they are polished shiny or pitted... these are signs of many hours of wear and prior corrosion...

5) Finding every inch of the main spar has some challenges... it is two sided... and really long... and hides under some tank sealant in some places...

6) the other place is the surfaces between the cam lobes and the cam followers...

7) When taking pics down the spark plug holes... it is important to have some good focus... and the pic is best when it includes the valves..!

It really helps to have a Mooney owning mechanic when doing a PPI...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Martin S.]

Thanks for the quick reply. She is in Germany. You‘re right, looking round the corner to check the valves makes complete sense. How about the peeling paint at the wing spar - does it male sense to run away already now - or would you peel off a little of the paint to see how the metal state below?

 

Martin

[Guest]

From your picture of the spar it doesn’t look like anything more than some missing paint at this point.  Some cleaning with a Scotch Bright pad to remove any loose paint followed by inspection will tell you the condition.

Clarence

[Martin S.]

Thanks Clarence, that makes complete sense to me. I‘ll try to convince the owner of letting me do this.

 

Martin

[Guest]

6 hours ago, Martin Stolle said:

Thanks Clarence, that makes complete sense to me. I‘ll try to convince the owner of letting me do this.

 

Martin

If you can secure some epoxy primer and some white paint to touch it up with how can he be unhappy?

Clarence

[Martin S.]

Me again guys,

 

could you comment on this? Lookd like oxidation - I don‘t like it. Hard to tell though whether it is serious or not!

 

Martin

[Guest]

I’ve seen issues with failed rivets in the rear spar caused by exfoliation of the angle sections of the spar.  Careful further inspection is called for.

Clarence

[bradp]

Clarence can you orient me in that picture. Where are we looking?