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  • Re: High oil temp

    by » 13 years ago


    Hi Roger,

    I have a 912ULS on a Quicksilver GT500 and fly with a oil temperature of 250. I was told that since it was in the green line (up to 260) I should not worry about it. How might the "high" oil temperature affect the engine after 180 hours?

    Thanks,

    Carlos Montenegro

  • Re: High oil temp

    by » 13 years ago


    Hi Carlos,

    Your question may depend on what type of oil you use as to causing any damage. most likely not, but it would be nice to come down off of 250F. A mineral spirits type oil will break down much faster that a good full synthetic that can handle higher temps better.I would like to know what your CHT's are as the water temps are very close if you don't have a separate coolant temp gauge. You can lower the temps many times with the proper prop pitch. If you have your engine/prop loaded too much the engine temps tend to be high. What is your flat and level WOT engine rpm? For a ground adjustable it should be around 5500-5600 at your normal cruise altitude. If it is down around 5200 then this is overloading the engine which can cause harm and causes higher engine temps. I live in Tucson, AZ where it gets hot. My oil temps are never over 235F even when it's 85-100F OAT and I'm loaded heavy, I usually run around 215F-220F for cruise with CHT's around 210F.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: High oil temp

    by » 13 years ago


    Hello Roger,

    I am using Aeroshell Oilsport Sport 4, at 5000 RMP I see CHT of about 150 (I do not have good resolution in the gauge), water 170, oil 250, EGT 1250, the oil pressure reads 30. My level WOT is about 5500. I am using IRIDIUM plugs (DENSO IXU24 5309 which are equivalent to NGK DCPR8EIX according to DENSO). I use AVGAS 60% of the time and I am based at 1400ft ASL (estern Colombia). The engine has 180 hours since new.

    A new plug, spring and end are arriving next week for the oil pressure relief, I also ordered the current oil pressure sender. I am not so sure about the pressure reading (I made a direct reading that showed 45), so I am upgrading from the resistance sender to the current sender.

    My Oil Cooler is next to the radiator in the front of the engine (a pusher plane). I intend to increase the air flow through it. On a GT500 the engine is not covered so I am a bit puzzled about the high oil temperature since it seems it should get enough air through it?

    Carlos

  • Re: High oil temp

    by » 13 years ago


    Hi Carlos,

    With every other temp so cool at can't quite believe your oil temp is so high. If you have a reduced radius in one of the oil lines that would account for the extra temp. Check your oil lines and make sure none have a slight kink do to bending. One little trick is to swap out the CHT temp prop with the oil temp probe and see if it still reads high. The probe are identical. Don't apply any sealer to the threads so it makes a good contact.


    p.s.
    You can help keep leading in the engine down with 100LL using a lead scavenger like Decalin and running a higher cruise rpm like 5300. Why do you use Denso plugs instead of NGK DCPR8E's? I wonder if that might account for the cool temps.? I'm not sure. What's your OAT?

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: High oil temp

    by » 13 years ago


    Hi Roger,

    OAT 70-90 F

    I just read (http://www.conairsports.co.uk/4-stroke%20oil%20system.html#lowoilpressure ) that a combination of low oil pressure and high temp reading could mean low voltage or bad earth.

    I used the IRIDIUM since the person that installed the engine told me they were better (and he provided the Denso plugs). Should I go back to the NGK DCPR8E ?

    I just ordered the Decalin.


    Thanks,

    Carlos

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