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Posted

TJ,

Treating as a link improves things a bit.  Are there any more FF spikes in the 3.5 hrs of data?  Looking to see if the problem has cleared itself by going downstream and away vs. moved out of the way temporarily to show up again later.

Reminds me of a blocked artery.  Makes you want to be sure it is really clear before going back with the usual level of exercise.

i'm neither a doctor nor a mechanic, but this is an idea that comes to mind.

Best regards,

-a-

Posted
On 11/10/2015, 10:59:43, frcabot said:

Just have the bottom entry log for now. It's cryptic and I've asked the shop (One Stop Aviation in CA) to send me the work order. Basically, it sounds like the bottom was torn open and repaired as necessary, but not overhauled to new limits.  Parts that didn't need to be replaced or overhauled, such as the camshaft for example, weren't.

"Disassemble engine & inspect for prop strike. Magnaflux crankshaft & all steel parts. Zyglo case. Check for hidden damage. Counter weights worn. Replace rod nuts & bolts. Replace main & rod bearings. Replace seals, gaskets & c.w parts. Magneto inspection. See listed parts. All current AD's complied with. Reassemble engine, ready for installation."

I'll ask the mechanic for the top entry.

What you describe there......isn't that exactly the same as many overhauls that don't use a new cam ? BUT, the cam was checked, magnafluxed and visually checked. Sounds like it was a complete bottom overhaul. NOW, the cam has been visually checked and I assumed passed where many surprise overhauls start with a simple cylinder replacement it sounds like you are ok.

With all of that, if the filter and screen did their job there shouldn't be trash floating around (no hole in the piston). It would have been nice to have taken an oil sample. With what I consider a low time bottom, I would consider redoing all the cylinders....personally I would do (I did) the nickel coating process with new parts: guides, valves, pistons, pins, rings, recondition the rods and for good measure I would replace the rod bearings again unless yours were pristine. All you are betting on is metal didn't get in the main bearings and cam areas, journals/lobes. I would imagine that most damage/loose parts were larger and it wasn't just grinding metal into powder.

I feel like most mechanics would lean waaay toward saying overhaul given the option.

Unless the $$ for a new/fresh engine is worth it for a warm and fuzzy feeling to you. :-)

Posted
1 hour ago, carusoam said:

TJ,

Treating as a link improves things a bit.  Are there any more FF spikes in the 3.5 hrs of data?  Looking to see if the problem has cleared itself by going downstream and away vs. moved out of the way temporarily to show up again later.

Reminds me of a blocked artery.  Makes you want to be sure it is really clear before going back with the usual level of exercise.

i'm neither a doctor nor a mechanic, but this is an idea that comes to mind.

Best regards,

-a-

No further large FF spikes, checking next couple of flights were ok, then it went in for an annual, just goes to show that without a engine monitor, would have never known.  BTW, I never realized this because no CHT limit was reached, it wasn't till I reviewed my flights.  

Be careful out there.

Posted
19 hours ago, Hank said:

So why is it bad when Lycoming does this, but good when Garmin won't let their GPS communicate with your ipad?  :blink:

The reasons always come down to money. These are companies, not animals, they need money to survive and adapt accordingly.

Garmin has an almost identical business model to Apple.

You may wonder, why doesn't my _____ (phone, car, thermostat, etc.) do ______ (fill in some feature)? It is most likely because there is a patent and a royalty that someone does not want to pay.

Posted
3 hours ago, Tony Armour said:

What you describe there......isn't that exactly the same as many overhauls that don't use a new cam ? BUT, the cam was checked, magnafluxed and visually checked. Sounds like it was a complete bottom overhaul. NOW, the cam has been visually checked and I assumed passed where many surprise overhauls start with a simple cylinder replacement it sounds like you are ok.

With all of that, if the filter and screen did their job there shouldn't be trash floating around (no hole in the piston). It would have been nice to have taken an oil sample. With what I consider a low time bottom, I would consider redoing all the cylinders....personally I would do (I did) the nickel coating process with new parts: guides, valves, pistons, pins, rings, recondition the rods and for good measure I would replace the rod bearings again unless yours were pristine. All you are betting on is metal didn't get in the main bearings and cam areas, journals/lobes. I would imagine that most damage/loose parts were larger and it wasn't just grinding metal into powder.

I feel like most mechanics would lean waaay toward saying overhaul given the option.

Unless the $$ for a new/fresh engine is worth it for a warm and fuzzy feeling to you. :-)

It would be pretty close internally to a complete overhaul if the cam and crank were sent out and yellow tagged. In this case, Zyglo is a form of non destructive testing used to identify crack, corrosion and imperfections, but the crank was not measured. There is more to an overhaul than Zyglo and visual inspection

Posted

frcabot, you are a hero. Handled very well and put everyone back on the ground safely. An inspiring story and a lesson for us all. thank you for sharing.

The one thing I am curious about is how much power the engine continued to produce? Was it enough to sustain altitude or extend glide? Thanks.

Posted
On 11/13/2015, 10:26:52, 201er said:

frcabot, you are a hero. Handled very well and put everyone back on the ground safely. An inspiring story and a lesson for us all. thank you for sharing.

The one thing I am curious about is how much power the engine continued to produce? Was it enough to sustain altitude or extend glide? Thanks.

Thank you for your kind words. I don't think I'm a hero, but I think I did my job as I as I was trained to do it. So props to my flight instructors.  Our training really does work.  If anything, I actually feel a little safer in the air now.  I've always told myself that an engine failure is survivable, but now I've lived through it and proven to myself it's true.  I think I will be much more cautious about flying at night or in low IFR, though.

The engine continued to produce partial power, but not enough to sustain altitude.  It was enough to extend glide, and the engine failed a few miles short of the airport.  I was at 11K feet though at 160KTS TAS when the engine problems began, so even though I was 25 miles away from Bakersfield airport, I have quite a bit of speed to bleed off to get to best glide.  Mooneys, fortunately, are very aerodynamic and so I was able to get a lot closer while remaining at 11K feet or thereabout.  If I had been slower or lower, it would have been a tougher call, and I would have considered a field landing.

Posted

FYI I got the logbook entry for the top as well. ~1040 tach hours ago:

"Removed all cylinders and performed top overhaul.  New pistons and rings installed. Valves and seats reconditioned.  New gaskets and hardware used as needed."  Other stuff too like spark plugs services, oil change, new fuel hose, cleaned fuel nozzles, etc.

The Bakersfield mechanic said it wasn't a "top overhaul" because the valves were merely "reconditioned" instead of replaced. Seems like a pretty small distinction to me, but since there are valve problems and all...

Posted
2 hours ago, jetdriven said:

There is no legal definition of "top overhaul" but Lycoming says replace exhaust valves and that was not done. 

I'm curious, do you have a link to this?

Posted

I can't imagine somebody would call something they did an "overhaul", legal definition or not,  and not replace the exhaust valves. But I guess it happens.

Posted
Just now, frcabot said:

Thanks. I note this service bulletin is from 2012, whereas the top was done in 1990(!!!). I wonder if the standards have changed.

No, and replacement of exhaust valves is required for a major overhaul on a Lycoming along with a lot of other things.  As Jetdriven points out there is no such thing as a "top overhaul" it is just vernacular used when the cylinders are redone together at same time but the case is not done.

Posted
2 hours ago, M20F said:

No, and replacement of exhaust valves is required for a major overhaul on a Lycoming along with a lot of other things.  As Jetdriven points out there is no such thing as a "top overhaul" it is just vernacular used when the cylinders are redone together at same time but the case is not done.

Thanks. I learn so much from you (plural). What a terrific resource -- wonder how we survived before the internet.

Posted
12 hours ago, jetdriven said:

Is a Mandatory SB like a company AD issued by the head of sales vs an AD from the FAA?

Posted

No, from a regulatory standpoint the sb is not mandatory but the engine overhaul manual probably says so too, which is. 

Regardless, the sodium filled exhaust valves are different from others, and I wouldn't run one past 2000 hours.  

Posted
On November 9, 2015 at 2:53:50 PM, Loogie said:

Here is another perspective on the Q whether to overhaul or just replace cylinder.  

You have to have confidence that whatever repair you choose will give you peace of mind and confidence that you have a safe engine. 

The engine is past TBO, regardless of any repairs done in the past, bottom or top, they still don't count as an overhaul.  You can rationalize it as such but that engine has reached TBO w/out an overhaul.  And now it failed...

Ask yourself this, what will it take for you to feel safe and your passengers safe.

This is just my opinion for what it's worth...I would not do anything short of an overhaul on that engine assuming it was a good candidate for it, if it's not then I would get a new or an overhauled engine.  

But that is just one opinion...other folks are more comfortable w different angles, I am not.  I am am victim of my background and experience, single engine is a different state of mind, specially when you don't have the chute or the ejection seat option

again just a thought, hope it helps.

 

vr

Loogie

Like I mentioned on 9 Nov, there is no legal definition of a "top" or "bottom" overhaul.  Basically it is just a repair in the eyes of the FAA.   You basically have a past TBO engine. Any repairs done to it in between do not meet a Major Overhaul criteria, they are what the mechanic put in the logbook.   A lot of folks talk about top or bottom like it's an official term; not so, a top or bottom can mean many different things to many folks.  

 

If you repair this engine you will have a repaired engine after an engine failure, the time is cumulative from zero.  In terms of confidence it would be hard to have confidence in a repaired engine past TBO that has been repaired.  Off course you have to make that choice and feel comfortable with it. 

VR

Loogie

Posted
51 minutes ago, Loogie said:

Like I mentioned on 9 Nov, there is no legal definition of a "top" or "bottom" overhaul.  Basically it is just a repair in the eyes of the FAA.   You basically have a past TBO engine. Any repairs done to it in between do not meet a Major Overhaul criteria, they are what the mechanic put in the logbook.   A lot of folks talk about top or bottom like it's an official term; not so, a top or bottom can mean many different things to many folks.  

If you repair this engine you will have a repaired engine after an engine failure, the time is cumulative from zero.  In terms of confidence it would be hard to have confidence in a repaired engine past TBO that has been repaired.  Off course you have to make that choice and feel comfortable with it. 

One thing that is for certain is that whatever is done to the engine must be logged.

What we have here is two things:

  1. The personal comfort of the owner/pax flying with the engine after repair, and
  2. The perception of a future buyer WRT the state of the engine at purchase.

As you point out, forget what you call it and ask:

  1. Do I want to fly with a repaired or rebuilt engine post in-flight failure.
  2. Will anyone really be interested in a less than major repair after an in-flight failure.

Selling an object without full disclosure could attract litigation. Frankly, I think this is a no-brainer.

Posted
4 hours ago, jetdriven said:

No, from a regulatory standpoint the sb is not mandatory but the engine overhaul manual probably says so too, which is. 

Regardless, the sodium filled exhaust valves are different from others, and I wouldn't run one past 2000 hours.  

Does that mean that you'd pull cylinders on a perfectly running engine at 2000hrs?

Posted

The engine overhaul manual says that it recommends following SB240, but does not say that it is required.  Lycoming releases a new version of 240 every couple of years with each version longer than the one before. Its very possible that valves were not included in 1990.

Posted

Incidentally this discussion gives rise to an important question.

If an engine suffers sudden stoppage say from a prop strike the insurance will cover the tear down inspection. SB240W calls for "Mandatory Parts Replacement at Overhaul and During Repair or Maintenance."

I read this to say that anytime the case is split need to replace certain items "regardless of condition."

Does insurance typically cover replacing everything the SB calls for or do they argue it's not mandatory?!

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