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Thread: Another 320 lack of use case

  1. #1
    BlueFox's Avatar
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    Another 320 lack of use case

    My dads cub got a factory new engine about 300 hrs ago, but with his failing health - 20 some odd years went by with little flight time. It got fired up and ran for a 1/2 hour at annual. But no actual use. Dad ran the 15w-50 Aeroshell and believed adamantly that there was nothing corroded inside this engine. I deeply respected my Dads 50+ years of heavy diesel mechanic experience.

    I wanted to know if it was going to be safe to get it back in the air so we started with more or less a pre-buy inspection. Tinkered with several little items and surely lots left to do, the plane might look like a garbage truck from being literally out in the weather for 40 years, the aerothane is still shiney under the chalk. she needs a patch or two in the Poly fiber rag from bird damage and a few cold weather bullseye but pulled metal belly and the zinc chromate has done itís job on protecting the fuse all over pretty solid and air worthy aircraft. Compression was good in all 4 holes, but Luckily the mags wouldnít fire and we didnít get it running.
    Decided to pull a cylinder and get a borescope to look at the cam and lifters before we went any further.
    The lifters look trash to me. Betting the cam is worn because I think this corrosion was happening from the early 90ís on.
    Piston skirt looks trash as well.
    Less than 300hrs on this motor.
    Glad I didnít just run it and check the screen. I believe Itís easily repaired at this point vs run with metal pumping thru the whole engine as the lifters cut the cam lobes down to nubs.
    Going to tear it all down and start over!












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  2. #2

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    That sucks, I always wondered why I can leave a dozer parked for 15 years and go run it, and never have any corrosion issues at all, and I have opened stuff up thats been sitting 30+ years (diesels and old fords), and only have light rust up in the valve cover. But then you baby an aircraft engine and it corrodes the second you look away from it. Nature of the beast I guess!
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  3. #3
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    I agree, I have equipment that gets used seasonally and itís life expectancy is unlimited. He did baby the motor and changed oil a lot. I hated watching it set there and go to crap and now seeing what I see here I believe that taking specific precautions for ďstorageĒ of the engine must be done if you are not going to fly it regularly vs seasonally. Even then youíre taking big chances on it being preserved.


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    hotrod180's Avatar
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    It's pretty common for GA airplrane engines to go 20 or 30 years between overhauls.
    I wonder how many are "corroded" inside without the owner knowing,
    and last til TBO or beyond without making metal or otherwise failing?
    Cessna Skywagon-- accept no substitute!
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  5. #5
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    Quote Originally Posted by hotrod180 View Post
    It's pretty common for GA airplrane engines to go 20 or 30 years between overhauls.
    I wonder how many are "corroded" inside without the owner knowing,
    and last til TBO or beyond without making metal or otherwise failing?
    I have an O-360 with over 3,100 SMOH. I pulled cylinder 3 at about 2,800 hours for deteriorating compression. While it was off I checked the cam and lifters. I found no corrosion on the working faces or anywhere else. Working faces of the 3 visible cam lobes and their lifters were bright, shiny, and in perfect condition.

    This engine has run on Aeroshell 100W, with no additives, for at least the last 25 years. For the last 10 years it has seldom flown more than 50 hours per year. Sometimes it sits for up to 6 weeks without being run.

    Arizona is not often cold and damp like someplaces people keep aircraft.
    Last edited by frequent_flyer; 09-01-2023 at 11:32 AM.
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  6. #6

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    I’d bet that if you investigated other engines in normal use by typical private owners you’d find similar corrosion to that in the photos.
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  7. #7
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    The OP noted that his Dad had ground run the engine periodically. This is a habit that others used to be pretty common, but has been proven to be one of the worst things you can do to one of these engines if they're not being flown regularly. The key is to get the engine up to full operating temperatures for some period of time, to cook off the moisture that condenses in any engine after shut down.

    I attended the Lycoming Piston Engine Service School a number of years ago, and the instructors there discussed this extensively. Students asked about ground running and turning engines over by hand during periods of inactivity. The instructor stated DO NOT ground run an engine during periods of inactivity, and especially DO NOT turn a prop through prior to start or in lieu of running that engine.

    His recommendation for periods of storage was, at the very least, fly the plane, get the engine up to operating temps, shut down, change oil to Pickling Oil. There are other things, such as plugging all openings, that are also worth doing, but pickling oil was essential. He said then when you're ready to fly again, fly the first flight with the pickling oil, get engine up to temps, change the oil to your choice of approved oils, and fly it.

    Back in the day, these engines weren't that expensive to overhaul/repair. Nowadays, geeeeeez!

    MTV
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  8. #8

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    Lycoming says lots of things that pilots consider gospel and lots that pilots dismiss. There’s no rhyme or reason, but the practices persist.

    If a guy changes oil every 4 months regardless of hours per mfgr recommendation? I doubt ground running has any ill effects. If he doesn’t? Preservative oil is a good choice. The problem occurs when those two instructions are disregarded. Most of us have seen planes sit around with very infrequent use and they keep on running well. Many have seen airplanes ground run with the same results. Some of us have had healthy engines fail unexpectedly without warning and some fail very shortly after first start. I disassembled an 0-320 that was flown regularly and at 1200 hours was far, far worse than the OP’s photos. My observation is that rules are words and engines can’t read.
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  9. #9
    mvivion's Avatar
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    The key to longevity is to get the engine up to full operating temperatures regularly. This cooks off the moisture, as well as lubricating the engine internals.

    In winter, it can be difficult to get oil temps above 180 degrees, and keep them there for significant time, at least in cold climates. And that’s part of the problem: An engine may have been flown regularly, but did each of those flights result in engine internals reaching the recommended temperature and remaining there? If not, you didn’t meet the manufacturers recommendations. Doesn’t mean your engine will self destruct instantly. And, the next owner will likely have no knowledge of the prior history, at least in detail.

    Its not that mysterious, actually. Consider that flight schools offer some of the greatest abuse an aircraft can endure: huge power changes, over cooling during flight, etc, etc. Yet, those engines regularly go to or over TBO. They are regularly flown, with engine oil temps up to spec.

    MTV

    MTV
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  10. #10
    BC12D-4-85's Avatar
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    Use CamGuard and straight weight oil if flown infrequently? My choice.

    Gary
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  11. #11
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    Absolute hands down worst thing you can do is start a engine and not cook off the built up condensation. Second worse thing is leaving it outside without plugging the holes.
    Best bet is to crack the case and inspect everything. All the seals and gaskets will leak like a sumbich if you don't. I ran a 20 year pickled engine that was perfect but every seal and seam on it leaked including the case and through bolts. Save the drawn out hunt for leaks and just break it down. You with thank yourself in the end plus added peace of mind having put eyes on everything.
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  12. #12
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    Quote Originally Posted by stewartb View Post
    Iíd bet that if you investigated other engines in normal use by typical private owners youíd find similar corrosion to that in the photos.
    Iíve wondered if anybody had some comparable pics and how much time on the clock etc. In my circles Iíve witnessed a handful of these engines trashed from what appeared to begin as lifter spalling, eventually get metal in the screen and by then itís too late to save it. thatís why we pulled the jug.
    I think running the pickling oil could not hurt, and the more recent operating guidelines could really help avoid this. But really best to fly as much as possible.


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  13. #13
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    Quote Originally Posted by hotrod180 View Post
    It's pretty common for GA airplrane engines to go 20 or 30 years between overhauls.
    I wonder how many are "corroded" inside without the owner knowing,
    and last til TBO or beyond without making metal or otherwise failing?
    Now that I see these lifter faces and the appearance that they have been pitted and wiped off and pitted again several times, I been wondering the same thing. Iím 99% positive My dad would have fired it up and flown away as long as the screen was clear.
    In past decade or more I have too many known examples of post ďstorageĒ or lack of flight - cams going flat and metal in the screens after only a few hundred hours of time.


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  14. #14

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    The “trigger” to repair for most owners are sagging compression and making metal. In the absence of those conditions we keep on flying and totally ignore the Lycoming calendar life limit of 12 years without investigating like you did. Me? If compressions test well, it isn’t making metal, and it isn’t consuming excessive oil (a totally subjective value)? I’m flying it until it does.

    A friend has a Cub that saw infrequent use prior to his buying it a couple of years ago. It runs great but has started to make a little metal. His (very respected) mechanic suggests repairing it rather than overhauling. He asked my opinion. I told him it depends on what he finds at disassembly. If the crank and rod bearings look good and meet specs, and cylinders appear good? Going with what he knows is probably a good plan. He’s favoring an overhaul because he assumes that would be better. Better for what? That’s an interesting question.

    Good luck.
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  15. #15
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    Quote Originally Posted by stewartb View Post
    The ďtriggerĒ to repair for most owners are sagging compression and making metal. In the absence of those conditions we keep on flying and totally ignore the Lycoming calendar life limit of 12 years without investigating like you did. Me? If compressions test well, it isnít making metal, and it isnít consuming excessive oil (a totally subjective value)? Iím flying it until it does.

    A friend has a Cub that saw infrequent use prior to his buying it a couple of years ago. It runs great but has started to make a little metal. His (very respected) mechanic suggests repairing it rather than overhauling. He asked my opinion. I told him it depends on what he finds at disassembly. If the crank and rod bearings look good and meet specs, and cylinders appear good? Going with what he knows is probably a good plan. Heís favoring an overhaul because he assumes that would be better. Better for what? Thatís an interesting question.

    Good luck.
    I totally get the logic there and it really makes sense from a users perspective. Thereís not much common sense rebuilding a perfectly useable engine. Iíve heard some argument over the years that the cavities in the lifter face will just trap oil but I tend to believe it will cause wiping of the oil / disturbance + removal of any oil wedge that would get trapped between the lobe ramp and tappet face. While Iím new to this aircraft stuff I happen to be a 30+ year engine machinist and racing engine builder so Iím probably over sensitive to things being aceeptable for use. Talking with the AI the duration of time on the ramp with no real storage precautions taken. For myself, the fear of running a few hundred hours from here forward and becoming a soup to nuts lunchbox felt like too much of a preventable scenario. Iím not sure what we will find on teardown but Iím guessing it will get a full overhaul.
    Thanks for sharing your inputs and experience. I really appreciate it.


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  16. #16
    Steve Pierce's Avatar
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    I was doing a prebuy on a Carbon Cub SS with an O-340 with 138 hrs. Oil analysis showed it had been having high iron content. Most recent sample said normal.
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    Found this after cleaning the oil filter element in solvent.
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    Dumped the engine data and found many 30 minute flights where the oil temp did not get above 140 degrees. Removed the engine and split the case.
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    Cam looked like new which coincides with what I have always been told, that the lifters go first. I installed a new cam and DLC lifters and last I heard all was good for the new owner.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers
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  17. #17
    Steve Pierce's Avatar
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    On another note, I have found engines with way more metal in the screens/filter. Torn them down and found a cam lobe or two worn down very badly and no metal contamination in the engine. The screen/filter did it's job.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers
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    BC12D-4-85's Avatar
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    I've wanted a magnetic oil dipstick for times like this. Had it happen twice. Once from non-use, the other from valve sticking. Gets expensive. Edit: The first non-use engine I'd pull the prop through periodically out of ignorance. Wiped the oil off most likely.

    Gary

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    Quote Originally Posted by BlueFox View Post
    I totally get the logic there and it really makes sense from a users perspective. There’s not much common sense rebuilding a perfectly useable engine. I’ve heard some argument over the years that the cavities in the lifter face will just trap oil but I tend to believe it will cause wiping of the oil / disturbance + removal of any oil wedge that would get trapped between the lobe ramp and tappet face. While I’m new to this aircraft stuff I happen to be a 30+ year engine machinist and racing engine builder so I’m probably over sensitive to things being aceeptable for use. Talking with the AI the duration of time on the ramp with no real storage precautions taken. For myself, the fear of running a few hundred hours from here forward and becoming a soup to nuts lunchbox felt like too much of a preventable scenario. I’m not sure what we will find on teardown but I’m guessing it will get a full overhaul.
    Thanks for sharing your inputs and experience. I really appreciate it.


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    I just loaded my engine hoist into my friend’s truck. He pulled a cylinder yesterday and found cam and follower damage as expected. His plan is to replace cam and followers and reassemble. That plan may change if crank bearings exhibit any damage, which isn’t expected. I’m looking forward to how his mechanic chooses to disassemble. Leave pistons in cylinders? Remove rods? I like this stuff, especially seeing how others work.
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    BC12D-4-85's Avatar
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    Make sure the exhaust valves are free and not sticking. That can lead to cam and lifter wear.

    Gary
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  21. #21
    frequent_flyer's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    I was doing a prebuy on a Carbon Cub SS with an O-340 with 138 hrs.
    Another example of low time not being a good indicator of engine condition. Thanks.

    Every oil change on my new FX-3 I do oil analysis, open the filter and flush the element, filter the solvent, weigh the filter papers after they dry, log the mass of contaminants, and inspect contaminants under an X10 microscope.

    Obsessive? Maybe, but I wanted to find any problems before the Lycoming warranty expired.

    I still don't trust the FX-3 engine as much as I trust my 3,100 SMOH O-360. We have not been acquainted for as long.
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  22. #22
    Steve Pierce's Avatar
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    Quote Originally Posted by frequent_flyer View Post

    I still don't trust the FX-3 engine as much as I trust my 3,100 SMOH O-360. We have not been acquainted for as long.
    My brother had a C90 throw a rod on him and he ended up in a field upside down to stay out of some trees. We were coming off the cap rock from Lubbock headed east in a new to us PA16 when he asked me what my theory of the thrown rod was. I had been looking at the landscape and telling myself I could put this airplane in here or there what he said that. I had that uneasy felling of a new to me airplane. I told him I didn't know why it threw a rod and I didn't want to talk about it right now. There was a long, long silence.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers
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  23. #23
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    Quote Originally Posted by stewartb View Post
    I just loaded my engine hoist into my friendís truck. He pulled a cylinder yesterday and found cam and follower damage as expected. His plan is to replace cam and followers and reassemble. That plan may change if crank bearings exhibit any damage, which isnít expected. Iím looking forward to how his mechanic chooses to disassemble. Leave pistons in cylinders? Remove rods? I like this stuff, especially seeing how others work.
    Thatís kind of where Iím at, Iím not sure but think I want to put 160hp pistons in and just freshen up the whole motor. I canít believe how scuffed up the pistons are with only 223.5 hours. I see the cam issue yeah but the pistons skirts?

    So after some long nights thinking too much it takes me back to when that motor swap happened and was brand new (took off a 2000ttsn (timed out) narrow deck 150) it seems like it was winter time and the skis got put on and break in period for the new motor was in cold weather. Tied off to a bollard at the hangar and ran for a bit - then went up in the sky and buzzed around. But that was in the late 80ís! Low time doesnít matter - This motor / AC sat outside in the weather its whole life. Also brings me back to how this wide deck motor never ran as good as that narrow deck. The new motor was a dog. A pooch. Felt sick instead of snappy. Wish I still had that original 150 ! Dad sold it to a local guy with a pacer.

    I work out of town on the slope so I had to peel out and leave Pauly to crate up the pieces and push her outside. Iím headed back south soon and get to dig out my spare O-320 and pull a jug and see if that motor has spalling or needs anything. Hopefully I can put it on the Mount and go back together.


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  24. #24
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    Quote Originally Posted by Steve Pierce View Post
    My brother had a C90 throw a rod on him and he ended up in a field upside down to stay out of some trees. We were coming off the cap rock from Lubbock headed east in a new to us PA16 when he asked me what my theory of the thrown rod was. I had been looking at the landscape and telling myself I could put this airplane in here or there what he said that. I had that uneasy felling of a new to me airplane. I told him I didn't know why it threw a rod and I didn't want to talk about it right now. There was a long, long silence.
    Personally - I highly favor field proven equipmentÖ maybe thatís just survival instincts?
    Iíve blown up my share of motors at high speeds on the Terra firmaÖ. Throwing a rod in-flight AC does not sound like fun.


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    I had an airplane break a rod in-flight. I wasn’t flying it but the next few months were quite an adventure. I had sold the plane but the money hadn’t changed hands yet so I owned the problem. There wasn’t anything left worth overhauling in that engine. Big holes in the case, metal in every oil gallery. No damage to the airplane, though. By total chance I discovered that engine had a poorly administrated AD for the rods. With a little help from my lawyer Continental played fair with the replacement engine.
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  26. #26

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    Curious, how your dad's airplane was stored? Inside, outside, humid environment, what?

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