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  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
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  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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    Have you gone to the faa website and looked up AD's? Complying with ad's at overhaul can be expensive and most engine ads have to be cw at overhaul....just a thought

    Sent from my DROIDX using Tapatalk

  8. #8

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    LLuke, that's great info. I think one of your secrets is that you spend most of your time at low power steady cruise, and a low altitude so that would be very easy on an engine; and is unlike what most of us probably fly.
    For instance , I go back a forth from Aspen at 7800 feet to Denver at 5280 often, and I have to climb to 13,500 or 14,500 maybe higher enroute. The trip is less than an hour, but a climb and descent at ethier end. I have also flown to Texas, Phoenix, Santa Fe, and Oshkosh. I have done all of these in my T-34A (0-470)and Beech 36 TC. The 34 tends to run high oil temp in climb, and the 36 definitely tends to have high cly head temp in climb, right up to red line in the summer, even at 120 knots and full rich climb.

    As for the valve troubles, none in the 0-470, but a lot in the TSIO -520 UB. I don't think it is related to valve warping or cooling. I have never heard of that before, and also it is standard to cool down the engine at 1000 rpm idle for 4 min to cool the turbo oil and bearings.
    As far as everything that I have heard and seen and read the problem in not valves overcooling and warping; rather it is exhaust valves burning, seats burning, and leaking, from overheating. If cooling and warping was the issue it might also hit intake valves and we don't see any trouble with them.
    Also running your engines in the 180 , 185 may offer more air flown and better cooling over the engine that the tightly cowled Bonanza.
    Thanks a lot for your input.

  9. #9
    FlyingRon's Avatar
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    To my knowledge the big Continental engines doesn't have much in the way of AD's. There are a few to make sure you don't have certain after market parks (certain Superior Air Parts cylinders, etc...).
    The biggy is the crank controversy of the early-to-mid nineties but hopefully all that has been taken care of by now.

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