Lessons learned

[flyboy0681]

Just now, gitmo234 said:

To settle the debate, here’s a pic from the flight, about 2 hours after stopping to add oil.

I think we can all appreciate the mea culpa, which is a good thing.

After draining our oil and installing a new filter, my A&P refilled and ran up the engine briefly and reported no problems. This was his attempt to see if he could at least determine what the problem was (which he couldn't). However, the actual tear-down revealed the real damage.

 

[neilpilot]

Not likely relevant to the reported incident, but the oil changes done following the 3 annuals prior to your May purchase of N1300A (summers of 2014, 2015 and 2016) are curious.  They were all done by the same IA, and report a fill of only 5 qt of Aeroshell 100.  That seems about 2 quarts lower than what a normal IO360-A1A should receive.  

 

[carusoam]

Gitmo,

Thanks for posting the additional details...

I was wondering if there was a redline at the bottom of the yellow arc...

It is there.  It has a meaning. Your POH will write out what the meaning is in more detail.  Check the limitations section of the POH.

It probably notes that operating outside the redlines is bad.

Make sure the POH, and gauge all match.  Sometimes one gets replaced, but doesn't quite match the purpose.

I would be expecting a cylinder problem with the oil soaked plug.

Other things I would be looking for...

• Cutting open the filter for inspection
• oil sample sent to the lab
• Compression Testing on the cylinders
• Log book reading... how old/how many hrs on the cylinders and everything else....
• dental cam pictures down the cylinders... no hatch marks? Smooth bore? Scrapes?
• Filter the oil leaving the engine... See if any ring parts or anything else depart with the oil...

All this stuff would be on my data collection list to support my decision.  Any metal in the filter or in the oil analysis will make the decision much easier...

If the cylinders are ancient and run without an engine monitor, expect lots of wear indications...

Stuff that comes to the mind of a PP with ancient M20C w/o a JPI experience...

Best regards,

-a-

[gitmo234]

45 minutes ago, carusoam said:

Gitmo,

Thanks for posting the additional details...

I was wondering if there was a redline at the bottom of the yellow arc...

It is there.  It has a meaning. Your POH will write out what the meaning is in more detail.  Check the limitations section of the POH.

It probably notes that operating outside the redlines is bad.

Make sure the POH, and gauge all match.  Sometimes one gets replaced, but doesn't quite match the purpose.

I would be expecting a cylinder problem with the oil soaked plug.

Other things I would be looking for...

• Cutting open the filter for inspection
• oil sample sent to the lab
• Compression Testing on the cylinders
• Log book reading... how old/how many hrs on the cylinders and everything else....
• dental cam pictures down the cylinders... no hatch marks? Smooth bore? Scrapes?
• Filter the oil leaving the engine... See if any ring parts or anything else depart with the oil...

All this stuff would be on my data collection list to support my decision.  Any metal in the filter or in the oil analysis will make the decision much easier...

If the cylinders are ancient and run without an engine monitor, expect lots of wear indications...

Stuff that comes to the mind of a PP with ancient M20C w/o a JPI experience...

Best regards,

-a-

Thanks! Some of those have been answered. A borescope by the A&P revealed that the cylinders looked fine and a compression test read good as well, but there were other signs of things not being very good (a data point for the argument about validity for cylinder compressions).  Two cylinders have < 100 hours, 1 is a bit older, and 1 has all ~1100 hours on it. 

the POH is a bit generic being as old as it is. It says " Red line: minimum idling 25PSI" and "yellow arc idling range 25-60 PSI" and "operating range 60-90 PSI". So yes, bad. Oddly enough, I learned the answer to a previous question though, the electric fuel pump is not on the list of required operational equipment. Thats just something I noticed irrelevant to this conversation. 

I never caught (and neither did two A&Ps I had review the logs independent of any inspections and seller) the low entries on previous oil changes. So I suspect this has been a building problem that has finally just caught up to me. 

[gitmo234]

Also... I reviewed blackstone history on the oil, there were elevated metals but not to the point of concern. In fact it says something along the lines of "these are probably due to cylinders having <100 hours" and something along the lines of "keep running it"...

Actually, I found it and its attached. This is turning more and more into an episode of NCIS EDIT to reference my previous comment. More and more dots that by themselves are sort of meaningless. 

 

Edited November 26, 2017 by gitmo234

[carusoam]

Did you get to see the bore scope pictures/video...?

They are really interesting. Lots of surface detail...

Valve health is the other thing of value. Valves that have gone wonky usually have visual cues that go with that.

Oil usually has two methods of escape...

One, escape out the exhaust pipe... which means leak into at least one cylinder first.  Expect a broken oil ring to go with that...

Two, get blown out the case vent... which means exhaust is leaking into the case, pressurizing it, and pushing the foaming oil out the vent. The other rings are suspicious in this case...

Did you see any really dark, foaming oil? Exhaust blowing into the case can turn the oil really dark quickly...

PP thoughts only not a mechanic.

Best regards,

-a-

[gitmo234]

I didnt get to see the borescope. My memory is starting to blur a bit on it so I may be off, but he said there was oil puddled in two cylinders, but they looked okay and he suspected tapered cylinders, or maybe an intake leak. He said it could be as simple as some gaskets but there were other small clues that said it could be something bigger. There's a small plate and rod that attach between two cylinders and one of those had come off, which he said was extremely odd because normally you cant get them off when you want them off. The rubbery piece in between the individual rows on the cylinders had broken a bit, which he said was extremely odd too, and he pointed out some areas where it looked like someone had chased an oil leak and tried to seal it, and not make it obvious. There was some oil puddled on the top of the engine as well. Toward the back. 

[MIm20c]

I would send the engine to a trusted shop for an IRAN.  The reason is the low oil pressure and quantity might have caused some internal damage that could cause a problem down the road.  The shop will send out the crank and case to be inspected and catch any corrosion issues that might be starting.  Jewel has some fantastic pricing and I’m sure the IRAN cost will be considerably cheaper. 

[gitmo234]

Verdict 1 is in. The engine is and has been making metal for awhile. magnetic and non-magnetic

[bradp]

@gitmo234 you also have Aero Engines of Winchester less than an hour away from you.  They are another value shop by reputation.  I think @Shadrach has used them for a crank case repair.  They apparently do good work...

 

Please let us know where the metal is coming from.... cylinders, crank case journal bearings, cam... it's good for the rest of us to learn.

[gitmo234]

Unfortunately she's out in central Missouri. It really looks like I'm getting a major overhaul. He doesn't know the specifics of it yet, but there was enough metal in it that it was clear this was a building problem, and now it's at its limit. He's willing to ship it to jewell aviation but basically said that by the time he pulls it, ships it, overhauls the accessories that aren't included, and reinstalls it, its going to be the same price to just do it there, and I'll also get regular phone calls/updates, pictures, etc. 

He's quoting me about $20k out the door

[KLRDMD]

29 minutes ago, gitmo234 said:

He's willing to ship it to jewell aviation but basically said that by the time he pulls it, ships it, overhauls the accessories that aren't included, and reinstalls it, its going to be the same price to just do it there, and I'll also get regular phone calls/updates, pictures, etc. 

Assuming you plan to sell the airplane in the next 2,000 hours, a Jewell overhaul will mean more to a buyer than a "Joe Blow"overhaul. If you plan to keep it until the next overhaul, then the issue becomes less divided. You may also have a better warranty and/or ease of getting any issues worked out with a bigger shop than a one man place. Things to think about.

[Browncbr1]

put it back together, install an AOA and fly it to Jewell...      just kidding.

[gitmo234]

1 hour ago, Browncbr1 said:

put it back together, install an AOA and fly it to Jewell...      just kidding.

I've got an AOA so I'm halfway there

[Danb]

31 minutes ago, gitmo234 said:

I've got an AOA so I'm halfway there

And off you go, good luck