Engine failure

[Shadrach]

10 hours 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. 

VR

Loogie

Who cares what the FAA defines as an overhaul? As far as the FAA is concerned an engine can be reassembled to service limits and be called an overhaul. The information that we originally received suggested that both top and bottom had been apart in the not so distant past and that the oldest of the components had about 1000hrs in service. Your contention was then as it is now that the engine was beyond TBO by FAA definition.  The truth about this engine is that there was a great deal more do the story (all negative, the devil is in the details). The recent bottom turned out to be a 25yr old IRAN that's only flown a few 400hrs. The cylinders were more or less IRAN'd as well, not topped as originally stated.

I would not have even brought it up, but since you're quoting your own advice, I will restate that I think that your original advice was based on poor logic. It was your opinion that an engine that was thought to have 1000 hour cylinders and a 400hr bottom end needed to be overhauled because it was a 2100 hr engine due to the fact that everything had not been done together and thereby was not defined by the FAA as an overhaul. 

If someone puts $10,000 in fresh cylinders on an 1500 hr engine and the case cracks at 1800hrs would you recommend a complete overhaul? If they elected to do the bottom, the FAA would consider an engine with 0TT on the bottom and 300TT on the cyl an 1800hr engine. By the logic you've used, that engine is near timed out... Thankfully, engines don't perform on what people think (FAA or otherwise).

The engine in question is certainly a candidate for overhaul, but not at all for the reasons you originally and restated.

[jetdriven]

5 hours ago, Shadrach said:

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

For me, given how many engines just past 2000 hours have swallowed a valve, yes. For the hollow valve stem sodium-filled valves, I would.   I would pull all 4 jugs, swap exhaust valves.  Lap or reground valve seats as needed, new rings, light hone and put back together. To me it's like the magnetos, 500 hours isn't regulatory but it's compelling because you can't predict failure and a failure is too serious.  

[Loogie]

4 hours ago, Shadrach said:

Who cares what the FAA defines as an overhaul? As far as the FAA is concerned an engine can be reassembled to service limits and be called an overhaul. The information that we originally received suggested that both top and bottom had been apart in the not so distant past and that the oldest of the components had about 1000hrs in service. Your contention was then as it is now that the engine was beyond TBO by FAA definition.  The truth about this engine is that there was a great deal more do the story (all negative, the devil is in the details). The recent bottom turned out to be a 25yr old IRAN that's only flown a few 400hrs. The cylinders were more or less IRAN'd as well, not topped as originally stated.

I would not have even brought it up, but since you're quoting your own advice, I will restate that I think that your original advice was based on poor logic. It was your opinion that an engine that was thought to have 1000 hour cylinders and a 400hr bottom end needed to be overhauled because it was a 2100 hr engine due to the fact that everything had not been done together and thereby was not defined by the FAA as an overhaul. 

If someone puts $10,000 in fresh cylinders on an 1500 hr engine and the case cracks at 1800hrs would you recommend a complete overhaul? If they elected to do the bottom, the FAA would consider an engine with 0TT on the bottom and 300TT on the cyl an 1800hr engine. By the logic you've used, that engine is near timed out... Thankfully, engines don't perform on what people think (FAA or otherwise).

The engine in question is certainly a candidate for overhaul, but not at all for the reasons you originally and restated.

You make my point, anyone can call it a top or bottom, but in reality it can mean many different things, that is why the FAA defines a major overhaul, yes it matters.

Your argument has traction, but I certainly wouldn't be comfortable repairing this engine, I would overhaul it.  But that's just me an opinion, you are more comfortable with your knowledge etc, I have no problem with your advice but if was me I would overhaul it.  Fact that you don't like my reasoning is irrelevant, I feel it's important to hear both opinions, after all that is all it is, an opinion...

cheers

Loogie

[Shadrach]

10 minutes ago, Loogie said:

You make my point, anyone can call it a top or bottom, but in reality it can mean many different things, that is why the FAA defines a major overhaul, yes it matters.

Your argument has traction, but I certainly wouldn't be comfortable repairing this engine, I would overhaul it.  But that's just me an opinion, you are more comfortable with your knowledge etc, I have no problem with your advice but if was me I would overhaul it.  Fact that you don't like my reasoning is irrelevant, I feel it's important to hear both opinions, after all that is all it is, an opinion...

cheers

Loogie

What is in the engine log is what matters (provided it reflects what's in the engine). If all of the work performed is equal to that of an overhaul but the the components are installed 100hours apart, the fact that it does not fit the FAA definition of overhaul is symantics and nothing more; it is completely irrelevant when talking about engine condition.

It's not personal and it's not about what I like or don't like. It's about what's inside the case.

[Loogie]

Yes you are correct, but the problem is the logbook entry needs to be very detailed, and the reader has to be well versed in the details of the logbook description.  I think we would all agree that there are lots of entries made that are sloppy and misleading at best.  If the entries are clear, concise and accurate, sure, your argument makes perfect sense.  

In my case I would have to consult w a qualified mechanic that could make that assessment, since i am not qualified to determine if a repair met overhaul criteria.

 

 

[Shadrach]

1 hour ago, Loogie said:

Yes you are correct, but the problem is the logbook entry needs to be very detailed, and the reader has to be well versed in the details of the logbook description.  I think we would all agree that there are lots of entries made that are sloppy and misleading at best.  If the entries are clear, concise and accurate, sure, your argument makes perfect sense.  

In my case I would have to consult w a qualified mechanic that could make that assessment, since i am not qualified to determine if a repair met overhaul criteria.

Agreed. This hits home for me because a fellow member of this board who was plane shopping had a broker tell try to scare him away from a competing aircraft. The competing aircraft appeared to be a meticulously maintained and well equipped vintage Mooney but the top and bottom were done a few hundred hours apart. The broker insinuated he plane was unsafe because it had not had a "major overhaul" and said he would not allow his family in such a plane. I'm assuming the broker was just trying to deter his prospect from purchasing an alternate aircraft, but it's possible that he truly believed what he was shoveling.

[frcabot]

Resurrecting this thread from the dead. I did end up going with Corona. I think the work they did was OK but it took way longer than they estimated, plane was out of commission for over 3 months. 

I forget if I went with new or overhauled cylinders, need to check. 

The overhaul, plus the labor from the mechanic in Bakersfield, plus the tax, made for quite a bill. I hope the engine goes for another 2000 hours because if not, it will have been a really shitty experience.