Supply chain and Overhauls. Who is affected and how?

Eagle_ said:
some shops offer ready to go engines that have been overhauled, you receive a zero timed engine immediately, and you have to pay based on the condition of the core you bring in. It’s more expensive than an overhaul of your own engine off course, but if you want the least possible downtime, that’s the way to go, unless you have a spare engine of your own to swap out.
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Some shops? Only the factory (or AUTHORIZED shops, and AFAIK there are none) can Zero Time an engine?

0 Since Major Overhaul is NOT a 0 time engine. All the hours ever run on that engine continues in the log and continues to accumulate.

A Zero Time engine comes with a new logbook and a new serial number and truly starts again with 0 hours.
 
I agree^^^^^ doubt many shops can afford to have fresh engines in stock on the shelf?
Maybe if they specialize in one engine type?

2 years ago when I bought my engine from lycoming they had 3 options. Actually only 2 options for the motor I wanted.

New engines, some models with 0 time.
Overhauled engines with time on them.
And rebuilt like mine was with 0 time.
I think they used to call rebuilt "remanufactured"?

Here's what came with my rebuilt engine and a new log book.
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One counter point. Had a cylinder fail compression test Friday. New cylinder will be at shop Monday or Tuesday. Lycoming O360.
 
Did they do anything to see if they could get the compression up? Where was it leaking? Valves or rings?

Read Mike Busch. WAY to many times, the answer is pull they cylinder, when less invasive means would have fixed the issue.
 
mr_happyland said:
Where did you get your cylinder from?
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Not sure the source, they use Zephyrhills for rebuilds who quoted 7-10 days depending on part availability. I'll post next time I stop by the shop.
Pinecone said:
Did they do anything to see if they could get the compression up? Where was it leaking? Valves or rings?
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Rings - quite a bit of time trying to reseat them. Last try compression was around 45. Could hear oil gurgling in the crankcase and I've had a bit more oil on the belly the last few months. I watched the last test, not flying that plane without replacing the cylinder, and I've listened to Busch, though even at 2.5X replay speed, he takes way too long to make his point.
 
Hang 4 said:
Not sure the source, they use Zephyrhills for rebuilds who quoted 7-10 days depending on part availability. I'll post next time I stop by the shop.
Rings - quite a bit of time trying to reseat them. Last try compression was around 45. Could hear oil gurgling in the crankcase and I've had a bit more oil on the belly the last few months. I watched the last test, not flying that plane without replacing the cylinder, and I've listened to Busch, though even at 2.5X replay speed, he takes way too long to make his point.
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try playing it backwards with a lava lamp on…
 
Hang 4 said:
Rings - quite a bit of time trying to reseat them. Last try compression was around 45. Could hear oil gurgling in the crankcase and I've had a bit more oil on the belly the last few months. I watched the last test, not flying that plane without replacing the cylinder, and I've listened to Busch, though even at 2.5X replay speed, he takes way too long to make his point.
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Read his books.

Did they do a ring flush?
 
Pinecone said:
Read his books.

Did they do a ring flush?
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No - but have had symptoms for 6 months. Thought is was a sticking exhaust valve early on. Morning sickness symptoms as EGT's were slow to come up. Replaced upper sparkplugs on the last oil change which improved the morning sickness, but still had more oil on belly than usual. If it was some carbon stuck on the rings, it would have been gone by now. Rest of compressions are fine. This cylinder is toast.
Busch has some good ideas, but he's not God. Most of his ideas do not require a book to get the concept. All his stories of saving someone from a disaster annual have common theme of an owner that doesn't know how an engine works or a lazy/incompetent mechanic. I know engines (Rebuilt a 911 myself) and my A&P know's his stuff and I trust him. I'm not taking my family up with that cylinder.
 
No, he is not. But he has gathered a lot of information and presents it in an understandable manner.

It sounds like you would the perfect candidate to try a ring flush. No, the carbon does not leave the rings. When the rings stick, the lack of ring tension means more oil is added which causes more buildup and more sticking.

Your plane, do what makes you feel most comfortable. I would rather not have to pull a cylinder.
 
Pinecone said:
It sounds like you would the perfect candidate to try a ring flush. No, the carbon does not leave the rings. When the rings stick, the lack of ring tension means more oil is added which causes more buildup and more sticking.
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And 6 months at least of the piston slapping around in the cylinder. If it had just come up, I'd give it a whirl. I'm 99% sure the cylinder will be out of round.
 
Pinecone said:
Some shops? Only the factory (or AUTHORIZED shops, and AFAIK there are none) can Zero Time an engine?

0 Since Major Overhaul is NOT a 0 time engine. All the hours ever run on that engine continues in the log and continues to accumulate.

A Zero Time engine comes with a new logbook and a new serial number and truly starts again with 0 hours.
Click to expand...

I meant 0 SMOH, it’s a reset of the timer. You don’t need a true 0 timed engine anyway, otherwise there’s no point in overhauling your own engine? I really don’t get what you are trying to say here?
 
Gary Ward said:
I agree^^^^^ doubt many shops can afford to have fresh engines in stock on the shelf?
Maybe if they specialize in one engine type?

2 years ago when I bought my engine from lycoming they had 3 options. Actually only 2 options for the motor I wanted.

New engines, some models with 0 time.
Overhauled engines with time on them.
And rebuilt like mine was with 0 time.
I think they used to call rebuilt "remanufactured"?

Here's what came with my rebuilt engine and a new log book.
(edited)_(edited)_IMG_8286.JPG
Click to expand...

Some shops actually do have factory new engines on the self, but only some of the most common ones. They are sold as factory new too. A factory rebuild is still being offered as a factory rebuild. You can also get a factory overhauled engine these days, but that’s only an option if your engine is maximum 36 years old.
 
MIFlyer said:
how far in advance can one buy a reman before you have to send back the core. with prices going up, if you thought you needed it in the next two years, you could put the crate in your dry garage with dessicant plugs and then do the swap in a couple of winters when your current one dies. It's also almost worth having a cylinder on hand (either new or O/H) to avoid a long downtime over a 2,000 part
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Lycoming SL 250A says you have 120 days from the invoice date of the replacement engine before they need your core back.
 
Eagle_ said:
You can also get a factory overhauled engine these days, but that’s only an option if your engine is maximum 36 years old.
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Is the 36 years a EASA limit? I'm unfamilar of a similar limit for US engines and believe there are a few flying that well exceed 36 years of time.
 
Bell206 said:
Is the 36 years a EASA limit? I'm unfamilar of a similar limit for US engines and believe there are a few flying that well exceed 36 years of time.
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No, it’s a Lycoming limit, if your engine is over 36 years you have to get a rebuild, new or field overhaul. You cannot get a factory overhaul. It doesn’t mean you have a bad engine, just an old one.
 
I have to make a correction though. Those 36 years is since it last left the factory, in a rebuild, new or overhauled state. So if you had factory overhauls performed in the past, it’s still accepted. But generally if you’ve had it overhauled in shops, it’s not.
 
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Eagle_ said:
Sure, check Service Letter 250A
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Okay. Its a engine core policy not part of an engine overhaul schedule. Minor detail but big difference on the other side. Learn something every day. Thanks.
 
I am curious though, what do you mean by schedule, something like the 12 year tbo?
 
Eagle_ said:
I meant 0 SMOH, it’s a reset of the timer. You don’t need a true 0 timed engine anyway, otherwise there’s no point in overhauling your own engine? I really don’t get what you are trying to say here?
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You stated after an overhaul that it was a Zero time engine. It is NOT.

These are specific terms in the regulations. An overhaul has specific requirements to be an overhaul, otherwise it is an IRAN. Zero time has legal meaning.

If you ever sell a plane with an newly overhauled engine and advertise it is Zero time, get ready for some push back from buyers.

Yes, in most cases an overhaul is all you need. But even then, all overhauls are not the same. See the thread about Jewell Aviation that was just posted.
 
Hang 4 said:
No - but have had symptoms for 6 months. Thought is was a sticking exhaust valve early on. Morning sickness symptoms as EGT's were slow to come up. Replaced upper sparkplugs on the last oil change which improved the morning sickness, but still had more oil on belly than usual. If it was some carbon stuck on the rings, it would have been gone by now. Rest of compressions are fine. This cylinder is toast.
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Just to close the loop on this sub-thread, looked at the removed cylinder today. Broken ring, and scored cylinder wall from the edge of the ring. Not even rebuildable. New Superior cylinder that was on the shelf at Zepherhills installed and waiting for VFR weather for a shakedown, break-in flight.
 
@Hang 4

Looks like you made a good call. Curious, you said six months to get to this point.
Can you cover what you did to debug/test to make the decision?

Thanks,

Tim
 
Pretty much covered where I quoted myself. Compression was fine at last annual. Noticed EGT slow to come up on that cylinder about 6 months or so ago. Suspected sticking valve (Morning Sickness). A bit later, checked spark plugs during an oil change and decided they were too worn to bother to re-gap. Installed new top plugs, bottom are fine wire and no issue, and sleepy start up seemed to go away and EGT came up normally. Figured that cured it. Went on a long trip a couple weeks before annual and noticed a bit of vibration that was a bit out of the ordinary. Annual started about 3 weeks ago and compression was very low, 45#'s. Thought it might be a stuck ring and A&P did a few things to try and free it up. None worked, so made decision to replace. Supply chain issues made rebuild timing questionable, so that was why I went with new on the shelf.
In hindsight, a few clues that I might have taken more seriously and would have acted on sooner if it was longer from annual. CHT's were running a bit higher than normal. I think that the rest of the cylinders were working harder to make up for the weak one. More oil than normal on the belly was another, though consumption was not that much different than normal. This was from blow-by through the broken ring and the rest of the rings getting coked up from all that blow by. Lastly, the increased vibration on the last trip. My wife noticed it right away. If I hadn't been going into annual anyways, I would have had it checked before flying again.
 
Additional details helps. So trend analysis was the primary thing which lead to investigations.
With my computer orientation (I work in IT for a living); and a few other threads I have read in the past year, would speak to the practice of downloading data for analysis; ideally it would include engine and avionics information (attitude, altitude, OAT...), This would likely allow for a much smarter and better analysis. I know Savvy has something, but I never did get around to using it. I have sort of wondered how good this field is.

Tim
 
I download my engine data to Savvy. It helps, but there's not a way to do much in the way of trend analysis. You only look at one flight at a time. What I could see very clearly is the bad cylinder's EGT's taking a long time to come up to where the rest were, which was explained by the crappy compression. There are so many variables, it's hard to do much in the way of trend analysis anyways, unless you have some pretty high horsepower analytics tools. CHT's can be influenced by fuel flow, intake leaks, ambient temp, power setting etc. You can also have multi variant issues or something transitory like a baffle seal that doesn't fold down the right way.
 
I would have to go look at logbooks for exact time frames, but I rebuilt engines in both my planes in 2021 and I think each one took about three months. These were field overhauls and I personally chased the parts and machine work for both. The holdups were the machine shops because they were backed up with so much work. Getting the replacement parts was really no delay, except maybe my fainting when told the prices and having to be treated with smelling salts before reviving to write the checks. IIRC, cases and crankshafts were about 8 week wait times. I live not far from Tulsa so I was able to get stuff pretty quickly once they finished. I got good work quality from the shops though.

One item that was difficult to source was the DLC lifters for the Lycoming. These are Diamond Like Coating that help solve the Lycoming lifter spalling problem. The young parts man at Aircraft Specialties got them for me just in the nick of time before reassembly. He is very focused at sourcing parts and helping customers. He is a great resource. IIRC his name was David.
 
Eagle_ said:
some shops offer ready to go engines that have been overhauled, you receive a zero timed engine immediately, and you have to pay based on the condition of the core you bring in. It’s more expensive than an overhaul of your own engine off course, but if you want the least possible downtime, that’s the way to go, unless you have a spare engine of your own to swap out.
Click to expand...

Depending on the specific engine make and model this is not a very common situation the days. Many engines are just flat not available on the engine rebuilders racks any longer.
 
Pinecone said:
You stated after an overhaul that it was a Zero time engine. It is NOT.

These are specific terms in the regulations. An overhaul has specific requirements to be an overhaul, otherwise it is an IRAN. Zero time has legal meaning.

If you ever sell a plane with an newly overhauled engine and advertise it is Zero time, get ready for some push back from buyers.

Yes, in most cases an overhaul is all you need. But even then, all overhauls are not the same. See the thread about Jewell Aviation that was just posted.
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Do you happen to know what the exact requirements are for an overhaul? Seems like everyone has an opinion rather than a link to a spec. The faa 43.2 an and b doesn’t spell everything out. Maybe it’s only done at AP school or something and I’m looking in the wrong places. TIA
 
Randomskylane said:
The faa 43.2 an and b doesn’t spell everything out.
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It does as bolded below. So unless you want to get a different set of standards and data FAA approved, the TC holder Overhaul Manual is the reference used when performing and signing off an overhaul per Part 43. And Part 43.13(a) provides further guidance to use the OEMs manuals. Some CRSs have gone beyond and had in-house overhaul procedures approved but outside that most shops and mechanics use the OEM manuals which details everything.

43.2 Records of overhaul and rebuilding.​

(a) No person may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being overhauled unless-

(1) Using methods, techniques, and practices acceptable to the Administrator, it has been disassembled, cleaned, inspected, repaired as necessary, and reassembled; and

(2) It has been tested in accordance with approved standards and technical data, or in accordance with current standards and technical data acceptable to the Administrator, which have been developed and documented by the holder of the type certificate, supplemental type certificate, or a material, part, process, or appliance approval under part 21 of this chapter.
 
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