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Thread: IO-520A pre-buy advice?

  1. #1

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    IO-520A pre-buy advice?

    Hope this is not too far off topic, i am looking at a Navion to purchase that has been modified with an IO-520A engine. It is a run-out so I'm assuming we'll be changing out for a rebuilt in the near future. My question is, is there anything I need to be especially aware of in regards to this particular model engine? I am looking at couple different planes with different engines,(io-520BA, io-470H) but his one has most of the options etc I want. Just want to know what the reputation of this model engine is.
    Thanks
    Dave

  2. #2
    EAA Staff / Moderator Hal Bryan's Avatar
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    Dave - just FYI, I moved your post from the other thread to start this one as I thought it was distinct enough to merit its own discussion.

    Cheers -

    Hal

    Hal Bryan
    EAA #638979
    Online Community Manager
    EAA—The Spirit of Aviation

  3. #3
    FlyingRon's Avatar
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    Can't say I know any problems with the -A in Navions off the top of my head. You might try on yahoo groups in navion_aircraft_mail.

    One thing to investigate (since it is run out) if this model is eligible for one of the "rebuild into an IO-550" mods.
    Under what authority was it installed? I am only aware of authorizations for =B, -BA, and -BB.
    What model Navion is it in?

  4. #4

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    IO-520A pre buy advice?

    I am looking at that option as well. This particular airplane has a one-time STC for the install. It is an "A" model that has the "beef-up kit" installed to allow for engines over 250 hp. It's just that if we go the upgrade to IO-550B route, the engine cost about 10K more, then its new tubular mount, fiberglass nosebowl and basket, new induction, exhaust, plus the STC, plus a lot of little things that add up to big$$$. So it would be much cheaper to stay with the same model. That's why I was hoping for input as to any particular weaknesses to the engine that would not be addressed in a "new" rebuilt IO-520A from Continental.
    Any help is appreciated.

  5. #5

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    I had a T-34 A with a Cont O-470, leaked some oil, but ran and ran, not much maintenance. Not a lot of power, ok down low, hard to get much climb over 12,000 or so.
    I now have Beech with a TSIO 520. Lot's of maintenance, often trouble with exhaust valves, overheating cylinders in climb. IO -550 seems some of the same, maybe a litttle less trouble. More power down low, still runs out of power if you need to go high.That is where the TSIO shines, I have been to about 19,000 with some more left.

  6. #6
    FlyingRon's Avatar
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    The other problem is that the Russel Druett mount/cowl/STC kits are currently unavailable. Russell (Sr.) was killed in a car crash last year. His son hasn't quite figured out what to do with the business last I heard.

    I've had an IO-550-B (on the Druett mount...which I have the world's record in turn around time getting delivered I believe). I've not had any problem with the engine other than the idiot starter drive adapter (finger pointing between Continental and Niagra).

  7. #7

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    I recently heard that Ryan Douthitt of Chino may have the STC or something very similar soon. Let's hope so.

  8. #8

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    IO-520 is a good engine. Take a good look for case cracking in the pre-buy as that will add about $10 grand to an overhaul if the case halves have to be replaced, they can be welded if not to bad and the early ones are known for cracking.

    We change many more cylinders on our O-470,s than on the 520, and it make considerably more power than a O-470. When broken in properly, ours do not burn any oil and make TBO (we overhual at TBO). It will burn about two more gph than the O-470.

  9. #9

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    Thanks for the info. I'll report how the inspection goes.

  10. #10

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    I am not personally familiar with I 0 -520, but I know a lot about the TSIO 520, mine and friends. I have not heard of any of them making it past 1000 hours without some problem with exhaust valve leaking, burning. Of course Cont claims it is all the pilot's fault; just like Beech used to claim problems with the tails falling off V tails was all the pilot's fault. Now these same type pilots did not have tails falling off when they flew Mooneys, like mine, nor did they have compression problems or valve problems when flying Lycomimg.
    I have heard that the non turbo, IO 520 or 550 is NOT free of such problems, may have a few less, may run a little cooler in climb.
    I agree that Cont 520 s don't burn much oil, they just burn up the exhaust valves. Oil would be a lot cheaper.
    For the reader who says his go to TBO, I'd like to hear details, what plane, where, who is the overhauler, what cylinders?
    I forgot to mention case cracking. One very experienced shop told me that most of the cracks are around the area where the gear driven alternator mounts on the front right of the case. He says extra balancing of the alternator helps the problem. My plane had a cracked engine case for the previous owner, and i had one on another engine. Cont probably claims it is the pilots fault also, maybe we take off the cowling and jump up and down on the alternator.

    As for as blaming pilots for factory or design problems, funny thing happened with V tail Bonanzas. Once the FAA, and Av Consumer magazine forced Beech to admit their really was a factory problem; and they issued an AD to check control cables, ruddervator balance and in some cases ad reinforcment, the problem of bad pilots or pilot error went away. I haven't heard of a V tail failure in years.
    A better plane seemed to make all the pilots as smart as when they were flying Mooneys.

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