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Thread: Rebuilding a Lycoming IO-360

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    Rebuilding a Lycoming IO-360

    Is it realistic for a homebuilder to rebuild his own Lycoming IO-360? I am building a Cozy aircraft and I am thinking about engine issues. New engines are expensive. The run out engines look pretty cheap. I really like engines and engine work, but I have never worked on an aircraft engine. I have rebuilt a few motorcycle engines. In my experience rebuilding an engine is just about following the instructions step by step. Do many builder do their own rebuilds?

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    Registered User Robby's Avatar
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    Re: Rebuilding a Lycoming IO-360

    I don't think you can do that legally.

    You have to have some ( lots of ) training, (lots of ) tests and some pieces of paper that say you know what you are doing before you can just rebuild a certified ( and it IS 'certified', not 'certificated' - I don't know where that word came from - always sounded like something made up by someone once who was trying to sound knowledgeable - and now we're STUCK with it ! ) aircraft engine.
    They are about the simplest engines around but you can't just pull the jugs, crack the case, replace, hone, polish and put it back together and go flying.
    Wish you could, at least for one's self, but that is not the case.

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    Registered User djschwartz's Avatar
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    Re: Rebuilding a Lycoming IO-360

    Quote Originally Posted by Robby View Post
    I don't think you can do that legally.
    Yes you can. As long as the engine is going in an experimental amateur built aircraft you can do whatever you want with it. You can rebuild it, you can modify it, you can operate it outside the manufacturer's original ratings, anything. The only difference it will make is that the FAA may require a longer test period for the aircraft if it is decided that the engine is non standard. But even that is up to the designee who issues the airworthiness certificate.

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    Registered User Dan Thomas's Avatar
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    Re: Rebuilding a Lycoming IO-360

    If the engine in question has been flown infrequently or for many short flights or has been run on the ground without flying too often, or has been operated in cold climates, or if it's been many years since the last overhaul, internal corrosion can be a serious issue. Lycoming's crankshafts have hollow front ends (most of them) and if a fixed-pitch prop is fitted, that area collects sludge and moisture (the prop wicks the heat out of that end of the crank and causes condensation of exhaust gases) that causes pitting of the inside wall. If it's had a constant-speed prop on it the governor oil circulation will keep the crud from accumulating to a serious degree. Any pitting causes stress risers that weaken the crank and can cause cracks, and according to an AD on the subject, if the pitting can't be removed by honing .010" off the wall, it's junk. There were a very few failures due to this pitting, just enough to scare everyone into an AD that applies to 160 hp and up engines.

    Aside from that, engines as described above will have pitted cylinders and pistons and camshafts and all, and could cost a lot to rebuilt to a safe level. On the other hand, an engine from a flight school that runs them fairly hard and replaces them every two or three years is going to be pretty clean inside. Ours are still showing compressions in the high '70s and no metal in the filters when we take them off at 2000 hours. They'd be fine as they are, but the $13,000 core charge means that they go back to Lycoming.

    Dan

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    Re: Rebuilding a Lycoming IO-360

    Sorry Robby, the word IS certificated. Here's some examples to show the difference:

    I am a certificated Single Engine Land Pilot. Meaning that I hold that specific certificate.

    The use of "certified" looks like this:

    I am certified to fly an airplane. Meaning I have been approved by the FAA to fly airplanes... barely different, I know, but still different. I could make the same claim if my dad tested me on my ability to fly and told my mother, "I certify that he is capable of flying an airplane"... It wouldn't be legal since him certifying that I can fly certainly does not mean that I have a certificate.

    SO, when we talk about a "certificated engine", we are talking about an engine that holds a certificate presumably of airworthiness.... Which begs the question:

    If a homebuilder rebuilds his/her own "certificated" engine, it probably shouldn't be called "certificated" anymore... BUT if the FAA approves it for flight in a homebuilt, does it become "certified" for flight in that aircraft? Does an experimental engine in a homebuilt receive its own certificate? If so, it becomes certificated again, but only in that plane? makes my brain hurt a little thinking about it.

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    Registered User Dan Thomas's Avatar
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    Re: Rebuilding a Lycoming IO-360

    Quote Originally Posted by shafferpilot View Post

    SO, when we talk about a "certificated engine", we are talking about an engine that holds a certificate presumably of airworthiness....
    Certificated means that the FAA (or whatever relevant foreign governing body) has issued a Type Certificate for that model of engine (or airplane or propeller). The Certificate of Airworthiness is applied to the entire assembled aircraft and is in force unless there is some known defect anywhere in the aircraft that has more than a negligible effect on airworthiness.

    Type Certificate Data for the IO-360 is found here:
    http://www.airweb.faa.gov/Regulatory...$FILE/1E10.pdf

    Dan

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    Re: Rebuilding a Lycoming IO-360

    thanks for that clarification Dan

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    Re: Rebuilding a Lycoming IO-360

    Both words are mutually exchangeable. "Certificated" though sounds like "government-official-speak-to-obscure-what-they-mean" ;-)

    “Certified” and “Certificated”



    As for the engine, I recall you're allowed to work "under supervision" of a mechanic, even on an engine. Might be a way to do it yourself (mostly) at a lower cost if you want to keep it certified.

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    Re: Rebuilding a Lycoming IO-360

    I did the teardown and rebuild on my O-320 Lycoming for my Pitts. I just bought a parts catalogue and maintenance manual and followed the pictures and words. Since my airplane is licensed in the USA as Experimental, Amateur Built, I can do this legally.

    I have worked on and around various car and motorcycle engines since the 1960s. The Lycosaurus is just another engine, not hard to take apart or assemble. Designed to some of the 1950's finest technology.

    The Lycoming manuals are plenty good enough to do the work and have a useable engine. I have been over the 2700 redline a "few" times and it hasn't blown yet.

    Normally what you would do is take it apart, send the parts out for inspection and repair and/or purchase any additional serviceable used or new parts you need. Then you put the engine together again.

    There are companys who specailize in inspection, overhaul and repair of aircraft engine parts - the stuff you can't do at home, like machining the case. For example I sent the case to Divco and they worked their magic on it for about $900. I had the crank inspected by (aircraft specialties??) and found it was cracked. I bought a used serviceable one instead of a new one. The cylinders had been already reworked with new pistons and a valve job done 25 years ago but the engine was never finished or run.

    The engine uses hydraulic cam lifters which are a close copy of what GM used in their 1950s Buicks. The electric motor for the starter is also similar to a Buick starter of that vintage. The rocker arms are not adjustable for clearance so there are 4 or 5 different lengths of pushrods. You set the clearance dry - no oil in the lifter by swapping around, and maybe buying a few, the various length pushrods and then you are done. No further adjustment until the next overhaul.

    I don't know the rules in Canada, but here, if it is experimental, no problem doing it yourself.
    Wally
    Last edited by wally; September 28th, 2010 at 08:18 AM.

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    Re: Rebuilding a Lycoming IO-360

    Once an engine is hung on a homebuilt, it is not certified any more in the FAAs eyes. If you can find them, Lycoming and Continental have service letters saying they want the data plate of the engine back if it is on a homebuilt. Do we do it? No. Why? because we want our value out if something happens to the plane. If a homebuilder rebuilds it is not certified any more. It takes an IA signature on a 337 to assy. the engine if the case halves have been split on a certified engine to keep it certified, and a regular A&P at minimum has to finish the rebuild. Most people have friends that can do the paperwork trail. A certified engine may get less time on the fly off it is up to the DAR. The guy next door built an RV8 and had a non certified 360 in his 8 built by some well known RV engine builder; plane had a short fly off. His just finished RV7 has a certified new Lycoming 360; 40 hour fly off. Same DAR; its the DARs whim on how much he wants you to fly. He has suggested guidelines, and they dont tend to stick their necks out much. If you pull off the engine on your homebuilt, you are going to want an A&P to write in the logbook that it is back to certified standards; the person who hangs it on a Cessna without that is an idiot because they are liable; getting an A&P to sign it as good will cost.

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    Re: Rebuilding a Lycoming IO-360

    Another thing that affects the fly-off time is the engine-prop combination. If you are using a certificated type engine with a certificated type propeller that were originally certified to be used together on a production airplane, then typically they will usually assign 25 hours for the test time. But again, it is up to the inspector.

    For sure, if the engine says Chevy or Buick or something other than Cont or Lyc on it, you are gonna be flying in your test area a lot longer than 25 hours.

    I had an O-320D2A engine and a 74DM prop, which are together listed on the type certificate of a Piper Cherokee so he gave me 25 hours.

    Wally

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    Re: Rebuilding a Lycoming IO-360

    A 337 signed by an IA is not required for an engine overhaul of these engines, an A&P is all that's needed.
    Also a cirtificated engine can be used on an experimental airplane, and if so is required to retain the data plate and IS SUBJECT TO AD NOTES.
    Bill B

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    Re: Rebuilding a Lycoming IO-360

    Quote Originally Posted by wbecker View Post
    A 337 signed by an IA is not required for an engine overhaul of these engines, an A&P is all that's needed.
    Also a cirtificated engine can be used on an experimental airplane, and if so is required to retain the data plate and IS SUBJECT TO AD NOTES.
    Bill B
    Actually not. With an aircraft in experimental amateur built category any major repair or alteration requires the airworthiness to be re-issued with a new set of operating limitations. Anyone can do the work. But only a designee can return the aircraft to service. It cannot be done by either an IA or an A&P, or even the original builder with his EAB repairman's certificate unless they are also a designee. The only difference it might make with regards to who did the work is what the designee will require for a test period following the issuance of the new certificate. Note that this is often ignored for EABs, largely because there is no official way to know what the original configuration was for that specific EAB aircraft.

    ADs are a gray area. Neither the aircraft nor its components are required to meet the requirements for standard category operation and that includes maintenance procedures. However, the aircraft must be inspected annually to ensure there are no "unsafe" issues. While it is not clearly stated anywhere in the FAR's it is generally agreed that the issuance of an AD constitutes an "unsafe" situation. One area I've never seen tested but which should be legal for a EAB aircraft would be to devise one's own method of taking corrective action to address the safety issue for the EAB aircraft. With proper analysis and an associated flight test period that should be legal.

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    Re: Rebuilding a Lycoming IO-360

    This statement was lifted from a random AD for a Lycoming engine.

    This AD applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD.
    For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

    The FAA will stick to "if it is or was once a certified part, ADs apply"; if your modification interferes with the AD, you have to get a ruling; like someone would win that. The FAA gives that warning at all the IA renewals I have been to aimed at homebuilders. In the US ADs are mandatory.

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