Cracked Cylinder?

[josh019]

Hey guys need some assistance here. I am in the process of a prebuy on a 1970 M20C. During the prebuy the cylinder was borescoped and I was told there was a crack (see attached pics). I went to get a second opinion and 2 other A&P's say this isn't a crack and wouldn't worry about it. These are 2 pictures of the cylinder. He said he took the picture (attachment 1) and then cleaned inside and took the next picture (attachment 2) and can still see a mark. The compressions were in the 70's and there are no other signs/symptoms of a bad cylinder. 

So the question is - is this something that needs to be addressed or does anyone here have any experience with this? Should I move on with the purchase or is this a no go? 

 

Thanks everyone! 

[EricJ]

May not be a crack, but a dye penetrant inspection could tell for certain.   You'd have to pull the cylinder to do that, though, unless the crack were also evident somewhere externally.

You can always use that to negotiate the price down.   A crack isn't the end of the world, since cylinders are neither difficult nor prohibitively expensive to replace.

 

[carusoam]

+1 on Eric’s response...

Really important cracks are the ones in the engine’s case...  not very common, but something you may hear rumors about...

If you are in the middle of a pre-buy... why is your knowledgable mechanic not giving you the option to use a penetrating dye?

For a few cents of materials and a quick clean up.... he can tell you if you have a crack or you don’t...

Is your PPI just a precursory check of everything... or something that ends up as a full annual inspection..?

Best regards,

-a-

[josh019]

Thanks for the info. That’s a good call and I will ask him to perform that. 

He would have to pull the cylinder for that? Or would he be able to do it while still attached to the motor?

It was supposed to start as just a PPI and maybe turn into an annual but he is finding a lot of things and that he would call “unairworthy” in his opinion that other A&P and general common sense would say otherwise. 
 

That’s why I decided to ask I was starting to get the feeling I was maybe getting taken for a ride or something...

 

thanks!

Edited April 23, 2020 by josh019
Missing question

[Ragsf15e]

Remember, it’s not your airplane yet... you really want your prebuy mechanic to be anal and thorough!

If the deal is structured properly, the seller should be paying for airworthiness issues, not you.  If your mechanic does a half ass job and your next annual costs $13,249, then you’ll wish you had a more thorough prebuy!

A cylinder wouldn’t be the end of the world for me either, but would definitely cause me to get the price reduced accordingly.

[Paul_Havelka]

I can echo what's been said above.  Get your mechanic to make you a list of things that 1. NEED to be addressed NOW, 2. SHOULD be addressed now, 3. Can be deferred.  For a prebuy I would consider groups 1& 2 as items to negotiate with with group 1 that the seller will have to fix before you move forward, or at least negotiate the sale price to get them repaired before you take possession.  Group 2 is where your negotiating skills may come in to play.  These I would not consider to be airworthiness items YET but if not addressed very soon then they would be or they may be big ticket items to repair/replace/etc.  Group 3 would be the nit picky things that don't really effect anything but may drive a perfectionist crazy but this is an old beer can that flies, you can't want it and be a perfectionist at the same time.  Kind of our own oxymoronic situation. 

 

As far as the cylinder I know there are some owners that will not let potential buyers remove anything more than spark plugs, oil, and filter from an engine.  If the owner is willing to let you take the cylinder off to have it checked then by all means do so if you are still interested in the aircraft.  Maybe you can start the negotiating already with whatever airworthiness items that your mechanic has said he's found and see if it's even worth yours or your mechanics time to continue moving forward.

[Guest]

7 hours ago, josh019 said:

Thanks for the info. That’s a good call and I will ask him to perform that. 

He would have to pull the cylinder for that? Or would he be able to do it while still attached to the motor?

It was supposed to start as just a PPI and maybe turn into an annual but he is finding a lot of things and that he would call “unairworthy” in his opinion that other A&P and general common sense would say otherwise. 
 

That’s why I decided to ask I was starting to get the feeling I was maybe getting taken for a ride or something...

 

thanks!

As there are no standards for conducting a PPI, be thankful you’ve hired a fussy A&P.  Let him do the inspection, produce the list and review it with you.  I’d hate see you here posting about the crappy plane you just bought and the lousy A&P who missed serious items.  Mooneys have gone to the scrap heap at the first annual after purchase, don’t be one of those.

Clarence

[takair]

Looks like that “crack” is near the plug.  I once learned a poor mans dye penetrant trick that often works in similar situations.  The borescope improves on it.  While watching the scope, spray a little brake cleaner on the OUtside  of the jug and see if it wicks to the crack.  If it does, it is almost definitely a crack.  You can spray inside too, if it takes longer to evaporate from the location. it MAY be a crack.  These are crude, but easy checks without the need to pull the jug.  We used to catch cracks this way around exhaust ports where the lead residue would act like the powder of dye pen.  I would NOT declare airworthiness this way....for situational awareness only.

[Shadrach]

On 4/22/2020 at 10:54 PM, josh019 said:

Thanks for the info. That’s a good call and I will ask him to perform that. 

He would have to pull the cylinder for that? Or would he be able to do it while still attached to the motor?

It was supposed to start as just a PPI and maybe turn into an annual but he is finding a lot of things and that he would call “unairworthy” in his opinion that other A&P and general common sense would say otherwise. 
 

That’s why I decided to ask I was starting to get the feeling I was maybe getting taken for a ride or something...

 

thanks!

It’s a good excuse to pull the jug and get a look at the cam while you’re in there.  If you’re paying someone to do a PPI, you want them to be thorough and find every airworthiness item. I’m sure that you’re excited to get your new to you plane but a poor purchase decision will turn that short term excitement into months (sometimes years) of misery.

Edited April 25, 2020 by Shadrach

[josh019]

Thanks everyone for all the input. You all are very helpful for someone just stepping into the ownership aspect of aviation. 
 

 

[takair]

1 hour ago, josh019 said:

Thanks everyone for all the input. You all are very helpful for someone just stepping into the ownership aspect of aviation. 
 

 

 

1 hour ago, josh019 said:

Thanks everyone for all the input. You all are very helpful for someone just stepping into the ownership aspect of aviation. 
 

 

Josh...tell us a little more about yourself or add to your avitar.  Where are you located? 

[Guest]

3 hours ago, josh019 said:

Thanks everyone for all the input. You all are very helpful for someone just stepping into the ownership aspect of aviation. 
 

 

There is a PPI list in the downloads section under safety and techniques that you might find helpful

Clarence

[josh019]

On 4/23/2020 at 7:12 AM, takair said:

 

Josh...tell us a little more about yourself or add to your avitar.  Where are you located? 

I’m located at F70. Newish private pilot no other ratings yet. 

[gsxrpilot]

6 minutes ago, josh019 said:

I’m located at F70. Newish private pilot no other ratings yet. 

If I were you, I'd walk away from that C and give Bob a call.

 

[chriscalandro]

I’m not saying it’s not a great airplane, but it might also be the most expensive E in the world too. 
 

I vote not a crack, and if it is, might be a good opportunity for a new cylinder on someone else’s dime.

 

Edited April 24, 2020 by chriscalandro

[gsxrpilot]

11 minutes ago, chriscalandro said:

I’m not saying it’s not a great airplane, but it might also be the most expensive E in the world too. 

There was an E that sold last year in the $160K range. But in my opinion, this one is a better airplane for a number of reasons.