How many times can you overhaul an engine?

mandm

mandm

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Newbie student pilot here with some questions on the engines and overhauls.

When someone says overhaul, does that essentially mean take apart and rebuild the engine? But it is still the original engine, right?

So would an engine only be able to be overhauled once or twice and then need a brand new one? I think I saw for a brand new engine it was usually $5,000 more. (Let’s say for a 200hp single piston)

For airframe total time, is there a “limit” per say that an airframe can handle or would there be a lot more maintenance needed for a high time airframe?

Trying to get a better idea what to look for when searching for an airplane.

Thanks in advance!
 
An overhauled engine is taken apart, cleaned, all the parts inspected for cracks using various methods, measured to see that they're within tolerances, and some machining where necessary. In most cases an engine will get new valves, lifters and cam, and many will get entirely new cylinders and pistons. They get new bearings, gaskets and seals. if the OEM does it (Lycoming or Continental) the engine will get an awful lot of new stuff including magnetos and carburetor or fuel injection, and often a new crankshaft. The only "old" part in a lot of them is the crankcase.

Engines can be overhauled numerous times, as long as the components are still safe. They undergo a lot of inspection.

Few GA airplanes have an airframe time limit, but the Cessna 400/ttx/Corvalis has a 25,600 hour limit, IIRC. We'll see more airplanes get time limits at manufacture as time goes on, but basically, if the airplane is properly inspected and cared for it will last a long time. Airplanes don't get run over rough roads or salted runways or driven hard by reckless punks (usually). They don't usually get run until something fails and it crashes, though we see a lot of important components run to failure, like alternators, magnetos and vacuum pumps, which is entirely unnecessary. The manufacturers will often specify extra inspections as the airframe ages, but these aren't legally mandatory unless forced by an AD. They're still good to do, though, and sometimes I found stuff where the manufacturer told me to look.
 
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Great thank you for the explanation :)
 
Unfortunately the word overhaul has no definite meaning. Did they replace all old components with new except the case, cam and crank? Did they inspect and repair as necessary (also called IRAN) not replacing anything that is worn but still within limits. For argument sake a component that has a wear limit of 1 inch and has reached 0.9 iches does not need replacing. Should it have been replaced? Time will tell. Also, was it put back together properly? Might be worth wandering over here. See:

My point is that unless the word overhaul is defined it is meaningless.
 
Arnold said:
My point is that unless the word overhaul is defined it is meaningless.
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A smart owner demands all of the yellow tags and the like from whatever shop rebuilds the engine. That information tells the tale of the thoroughness of the overhaul. It also lets the owner show the next guy that (for instance) the crank hasn't been turned down to the minimum, so it probably won't need to be replaced at the next overhaul.
 
Arnold said:
Unfortunately the word overhaul has no definite meaning.
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FYI: overhaul is defined in Part 43.2 if you want to use that specific term in a maintenance logbook entry. Same if want to use the term rebuild/rebuilt in a logbook entry. From a maintenance stand point it's pretty straight forward what is considered IRAN, overhauled, or rebuilt and how it is signed off.
 
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Bell206 said:
FYI: overhaul is defined in Part 43.2 if you want to use that specific term in a maintenance logbook entry. Same if want to use the term rebuild/rebuilt in a logbook entry. From a maintenance stand point it's pretty straight forward what is considered IRAN, overhauled, or rebuilt and how it is signed off.
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Your knowledge is acknowledged I should have been more specific and said in aircraft advertising overhauled is an undefined term.
 
mandm said:
Great thank you for the explanation :)
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The engine is the data tag,, all parts can replaced except the data tag, no limit as long as you have a data tag.
 
Arnold said:
I should have been more specific and said in aircraft advertising overhauled is an undefined term.
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Not quite. Making any misleading or false statements concerning a part for a TC'd aircraft whether in advertising or other form is a regulatory violation per Part 3. So if you advertise an engine as OH'd it will need to meet the definition in Part 43.2 and have the appropriate record trail. This is the same FAR that pushed vendors to label various parts lacking Part 21 approvals as "experimental" even though it doesn't necessarily prevent the part from being installed on a TC'd aircraft. The devil's in the details.;)
 
mandm said:
Newbie student pilot here with some questions on the engines and overhauls.

When someone says overhaul, does that essentially mean take apart and rebuild the engine? But it is still the original engine, right?

So would an engine only be able to be overhauled once or twice and then need a brand new one? I think I saw for a brand new engine it was usually $5,000 more. (Let’s say for a 200hp single piston)

For airframe total time, is there a “limit” per say that an airframe can handle or would there be a lot more maintenance needed for a high time airframe?

Trying to get a better idea what to look for when searching for an airplane.

Thanks in advance!
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Eleventy times. Or a buck 150.
 
remember the question? what did he ask?
 
Arnold said:
Your knowledge is acknowledged I should have been more specific and said in aircraft advertising overhauled is an undefined term.
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Claiming SNEW, SFRM or SMOH still has specific meanings, which can be verified through the engine logbook. STOH has a non-specific meaning, but still implies a "top" or cylinder replacement which can be verified.

If the logbook says it's something, but it isn't actually, that's a different issue.
 
Bell206 said:
Not quite. Making any misleading or false statements concerning a part for a TC'd aircraft whether in advertising or other form is a regulatory violation per Part 3. So if you advertise an engine as OH'd it will need to meet the definition in Part 43.2 and have the appropriate record trail. This is the same FAR that pushed vendors to label various parts lacking Part 21 approvals as "experimental" even though it doesn't necessarily prevent the part from being installed on a TC'd aircraft. The devil's in the details.;)
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Gosh I wish everyone was as honest as you uncle helicopter. Unfortunately -- they are not.
 
Arnold said:
Gosh I wish everyone was as honest as you uncle helicopter. Unfortunately -- they are not.
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Well... for the ones who aren't a simple phone call will take care of that for you. Then again birds of a feather....:rolleyes:
 
mandm said:
So would an engine only be able to be overhauled once or twice and then need a brand new one? I think I saw for a brand new engine it was usually $5,000 more. (Let’s say for a 200hp single piston)
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You missed a zero. A replacement with a new engine would typically be in the $50,000+ range for a 200HP IO-360. Plus installation. Here's a good example: http://www.airpowerinc.com/productcart/pc/TLEngineDetail.asp?catID=33&prodID=9801

An overhaul would typically be around half that.
 
Airframe- check the type certificate data sheet for life limits. Small GA may not have them. Bigger aircraft will.
Real world- 10k hours is a lot for trainer type ac. Yes you can find gems but everything wears out at some point.

Engines- in theory they can be overhauled indefinitely. In fact, overhauls are only a recommendation for non commercial ops.
Real world- after 2-3 overhauls may as well exchange for a 0 time already overhauled or rebuilt engine.
 
Geosync said:
Airframe- check the type certificate data sheet for life limits. Small GA may not have them.
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FYI: for applicable aircraft, most component life limits have been moved to an Airworthiness Limitations section in the OEM maintenance manual or ICA vs the TCDS.
 
Tom-D said:
The engine is the data tag,, all parts can replaced except the data tag, no limit as long as you have a data tag.
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That is also how so many "high mileage" HD motorcycles are still out there. So long as the VIN does not change, it is still the same bike... :p
 
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Some maintenance terms may have a generally "accepted" but not a regulatory meaning. "Top overhaul" is one such term. Most understand that a top overhaul suggests that the cylinders were either overhauled or replaced with new ones but the feds don't ever define what a top overhaul consists of so you really have no idea unless you get an exact listing of what, if anything, was done to all the cylinders. Major Overhaul is a term that does have meaning anchored in regulation. The manufacturer of an engine defines what needs to be done to call it a major overhaul. Even so, there is some latitude in how the manufacturer's overhaul instructions are complied with. Certain parts have to be replaced with new for a major overhaul but some parts can be reused with nothing but a visual inspection or a dimensional check. Some parts can be reworked so that they meet the manufacturer's requirement for reuse. Many parts subject to wear that are allowed to be reused are defined as within service limits or within new limits. Obviously a part meeting the dimensional limits for a new part could be expected to wear longer than a part barely meeting the service limit so not all Major Overhauls are created equal. The devil is in the details but at least a major overhaul entails everything getting looked at and meeting some minimum standard.
 
Dan Thomas said:
Both Lycoming and Continental have Service Letters, periodically updated, that lay out the TBOs.
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Curious. Has Continental or Lycoming started to convert any older CAR 13 engine models over to Part 33 certification requirements that include a specific MM and an approved Airworthiness Limitation Section? I know around 2010 some of the new Lycoming model variants came out certified under Part 33 which had several required ALS inspections and caught a few unsuspecting APIAs off-guard come Annual time.
 
Bell206 said:
Curious. Has Continental or Lycoming started to convert any older CAR 13 engine models over to Part 33 certification requirements that include a specific MM and an approved Airworthiness Limitation Section? I know around 2010 some of the new Lycoming model variants came out certified under Part 33 which had several required ALS inspections and caught a few unsuspecting APIAs off-guard come Annual time.
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I don't know. I retired a couple of years ago and have been losing track of stuff, since I'm not consulting it constantly and getting notifications from the manufacturers. Pretty much all my work was with older designs anyway, the newest stuff being the engines in the Cirrus and Corvalis, and those airplanes were already getting "old."
 
Dan Thomas said:
I retired a couple of years ago and have been losing track of stuff,
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Same here. The only time I look for anything now is when someone calls and asks an off the wall question like the one I referred to above. But I wonder how many older APIAs will get burned on missing the required ALS inspections found on some of the new Lycoming engines models like the 500hr mag inspection.
 
NordicDave said:
I thought 500hr mag inspection were standard or common practice for Mags.
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It usually is, but it is still an optional requirement on most engines. To my surprise, Lycoming, and probably Continental, are using Part 33 to certify some of their newer model variants. Part 33 is set up differently than CAR 13, which most engines are certified under, and provides separate manual requirements to include the use of an approved Airworthiness Limitations Sections. And Lycoming conveniently listed several inspection requirements to include the 500 hr mag inspection. That means the 500 inspection is no longer optional but mandatory per 43.16 and 91.403 on those specific model engines. And since ALS requirements are found in 91 and 43 even the owner can be busted for flying over the 500 hr limit. Looks like the Lycoming legal dept is getting more involved in aircraft certification again.
 
43.16 Airworthiness limitations.
Each person performing an inspection or other maintenance specified in an Airworthiness Limitations section of a manufacturer's maintenance manual or Instructions for Continued Airworthiness shall perform the inspection or other maintenance in accordance with that section, or in accordance with operations specifications approved by the Administrator under part 121 or 135, or an inspection program approved under §91.409(e).


Unless there is an AD, this is not required.
 
Tom-D said:
Unless there is an AD, this is not required.
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Really. So you are saying... if a Lycoming engine has a signed, approved Airworthiness Limitation Section that requires a 500 hour magneto inspection, or whatever inspection, you believe it still requires an AD to be issued to comply with that inspection?
 
Bell206 said:
Really. So you are saying... if a Lycoming engine has a signed, approved Airworthiness Limitation Section that requires a 500 hour magneto inspection, or whatever inspection, you believe it still requires an AD to be issued to comply with that inspection?
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yes. most don't
 
Tom-D said:
yes. most don't
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Tom-D said:
yes.
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I really hope you're just playing your normal troll BS on this....

So how does your customer get around the requirement below if you state an approved Airworthiness Limitation inspection is not required unless an AD is issued?

91.403 General.
(c) No person may operate an aircraft for which a manufacturer's maintenance manual or instructions for continued airworthiness has been issued that contains an airworthiness limitations section unless the mandatory replacement times, inspection intervals, and related procedures specified in the section or ...have been complied with.
 

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show me a Cessna 172 airworthiness limitations on a 1956 172.

(c) No person may operate an aircraft for which a manufacturer's maintenance manual or instructions for continued airworthiness has been issued that contains an airworthiness limitations section unless the mandatory replacement times, inspection intervals, and related procedures specified in that section or alternative inspection intervals and related procedures set forth in an operations specification approved by the Administrator under part 121 or 135 of this chapter or in accordance with an inspection program approved under §91.409(e) have been complied with.


most has no airworthiness limitations section.
 
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if over the span of 10 years every part on the engine is systemically replaced, then 10 years later is it still the same engine it was 10 years prior?
 
Tantalum said:
Off topic.. where do you guys see the post numbers?

]
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I believe if you are viewing on a mobile device you won't see them. On my laptop the post numbers appear on the lower right, just right of the *Like *Quote and *Reply buttons.
 
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