Engine Rebuild... need some schooling

Ventucky Red

Ventucky Red

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I have a “newb” question regarding types of overhauls done on engines... As a note one of the planes I am looking at has a Lycoming 0-320 with about 2400 hours on it..

What are the different overhauls.. I am hearing the terms, field or general overhaul, a rebuild, and a factory re-manufacture? The third is somewhat clear and would this give me a zero time engine… And what about the other two?
 
The exact definition of an "overhaul" is somewhat convoluted. But with that said, One can perform a "field overhaul" with all factory new parts except the data plate, and it is still an overhaul, the time on the engine remains the same, except you get to say "x hours since major overhaul". Or you can replace only the parts required at overhaul, as well as the ones that don't meet service limits, The total time on the engine remains the same, and still be able to say "x hours since overhaul" Only the factory (or it's subsidiary) can "zero time" an engine. even though they only replace the mandatory replacement parts, and those which did not meet service spec.
 
Ventucky Red said:
I have a “newb” question regarding types of overhauls done on engines... As a note one of the planes I am looking at has a Lycoming 0-320 with about 2400 hours on it..

What are the different overhauls.. I am hearing the terms, field or general overhaul, a rebuild, and a factory re-manufacture? The third is somewhat clear and would this give me a zero time engine… And what about the other two?
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This is a very good question and one that many do not understand has many different meanings.

Only a Manufacturer can set an engine back to zero time. They have a name for each of these rebuilds.

Google EAA Webinars and listen to all webinars made by a man of the name of Mike Busch, I believe that is his name, others please correct me if I am wrong on Mikes Last name.

But listen or watch TBO and beyound and you will learn alot about when to overhaul and when not to overhaul.

I have learned a lot from these webinars.

If you have a problem finding these webinars I will post a link for you.

H.A.S.
 
The most important thing is to get a detailed list of exactly what the overhauler is going to do, then compare the lists and prices. There's too much slop in what can be called an "overhaul" to do otherwise. Look hard at what accessories are included, too.
 
Do you seem to think that your engine happens to need an overhaul? Here ya go if you haven't read this:
FAR 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 accepteble 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 applicance approval under §21.305 of this chapter.
(b) No person may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being rebuilt unless it has been disassembled, cleaned, inspected, repaired as necessary, reassembled, and tested to the same tolerances and limits as a new item, using either new parts or used parts that either conform to new part tolerances and limits or to approved oversized or undersized dimensions.
[Amdt. 43–23, 47 FR 41084, Sept. 16, 1982]
 
bluerooster said:
The exact definition of an "overhaul" is somewhat convoluted. But with that said, One can perform a "field overhaul" with all factory new parts except the data plate, and it is still an overhaul, the time on the engine remains the same, except you get to say "x hours since major overhaul". Or you can replace only the parts required at overhaul, as well as the ones that don't meet service limits, The total time on the engine remains the same, and still be able to say "x hours since overhaul" Only the factory (or it's subsidiary) can "zero time" an engine. even though they only replace the mandatory replacement parts, and those which did not meet service spec.
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Nicely done! :yes:
 
Ron Levy said:
The most important thing is to get a detailed list of exactly what the overhauler is going to do, then compare the lists and prices. There's too much slop in what can be called an "overhaul" to do otherwise. Look hard at what accessories are included, too.
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While your point is spot on, to describe it as "slop" may be a little excessive. The overhaul manual is rather specific about what you have to do.

However what you have to do really ain't much, for a direct drive Lyc:
NDT pretty much everything
Dimensional inspection of everything that slides or turns
Replace the rings
Replace the exhaust valves and keepers
Replace the gaskets
Operational checks specified in the manual

That list is just off the top of my head so it is likely a little short but its the gist of it. So long as everything meets service limits then we have a 0 TSMOH engine retaining all the prev TT.

No matter what I, or anyone besides the factory or it's approved shop do we can never ditch the TT, even if the only used part is the data tag. Lycoming can call an engine 0 time if they wish.
 
So, in the opinion of those responding; Is there any advantage to a Mfg rebuild over a Named shop rebuild over a Field overhaul, other than a zero time engine and log book?

What I am reading is that when the grey or gold folks get it you the owner have little control over what is replaced vs inspected and put back in place, but with a field overhaul you at least have some control over these decisions. Is that a fair assessment?
 
tmyers said:
So, in the opinion of those responding; Is there any advantage to a Mfg rebuild over a Named shop rebuild over a Field overhaul, other than a zero time engine and log book?
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Warranty and possible resale value, worthy considerations.
 
Duncan,

Are you confidant that an engine you rebuild will have an equal chance to make it to TBO as a Lycoming rebuild does?

Could it cost the aircraft owner less $$ for a local rebuild over a factory one?
 
Skylane81E said:
Warranty and possible resale value, worthy considerations.
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But that might be an education issue if in reality the factory may have left the old crank in since it met specs. Sounds like an attentive local mechanic may actually do a better job on a rebuild than the factory.
 
That's what my brain was wrapping around Jonsey. Knowing what you have bought and that the case you sent to the factory is the case you got back.
 
tmyers said:
Duncan,

Are you confidant that an engine you rebuild will have an equal chance to make it to TBO as a Lycoming rebuild does?

Could it cost the aircraft owner less $$ for a local rebuild over a factory one?
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Yes on both counts, but I do not have the pockets to offer a warranty. I'll keep you posted as my basic overhaul gains time, it is coming up on 10% TBO
 
tmyers said:
That's what my brain was wrapping around Jonsey. Knowing what you have bought and that the case you sent to the factory is the case you got back.
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My engine is a first run, I'll be damed before I send it to TCM and risk getting a 10,000 hr case back.

However I get free labor and am not concerned with resale so I doubt the engine will be "overhauled" any time soon. I expect that all work will be IRAN for the foreseeable future.
 
LDJones said:
But that might be an education issue if in reality the factory may have left the old crank in since it met specs. Sounds like an attentive local mechanic may actually do a better job on a rebuild than the factory.
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I could, no doubt. IF (big if) I was to take on an overhaul job for a customer the level of work would be up to the customer.

Want an IRAN? You got it!

Want everything to new limits? Sure thing!
 
Skylane81E said:
My engine is a first run, I'll be damed before I send it to TCM and risk getting a 10,000 hr case back.

QUOTE]


My thoughts as well. The original IO-360 in my Arrow started making metal at about 700 hours. According to the logbook a new engine was installed to replace it. This engine now has around 1350 hrs on it. Is there anyway to tell if it was a factory New engine or a Factory Zero time engine?
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tmyers said:
Duncan,

Are you confidant that an engine you rebuild will have an equal chance to make it to TBO as a Lycoming rebuild does?

Could it cost the aircraft owner less $$ for a local rebuild over a factory one?
Click to expand...

I just watched a friend, who is considered one of the leading Duke gurus, overhaul one of his Duke engines. I watched him spend hours balancing the rod assemblies within a half gram of each other. His attention to detail was amazing. When I first ran that engine I couldn't believe how smooth it was. I will take his field overhaul over a factory reman any day.
 
LDJones said:
I just watched a friend, who is considered one of the leading Duke gurus, overhaul one of his Duke engines. I watched him spend hours balancing the rod assemblies within a half gram of each other. His attention to detail was amazing. When I first ran that engine I couldn't believe how smooth it was. I will take his field overhaul over a factory reman any day.
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Exactly, it just depends. This isn't difficult work, but it is detail oriented and time consuming.

Honestly the biggest factor in making TBO will always be the use of the engine. I've seen engines become issues at 200hrs if not flown frequently and seen "cheap" overhauls go to nearly 3000hrs on flight school aircraft.
 
Skylane81E said:
Exactly, it just depends. This isn't difficult work, but it is detail oriented and time consuming.

Honestly the biggest factor in making TBO will always be the use of the engine. I've seen engines become issues at 200hrs if not flown frequently and seen "cheap" overhauls go to nearly 3000hrs on flight school aircraft.
Click to expand...

This.
 
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