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  • Re: Help Please - 912ULS Low differential pressure on Cyls 1 & 4

    by » 4 months ago


    Hi Brian - I am making a low cost suggestion, that may just work.

    I am getting on in years and remember when "glazing" of engine bores, particularly with city based vehicles, was a problem. City based vehicles  rarely got up to optimum operating temperature/speed for an extended period (say min 30 minutes per day) - the result was a failure of the piston rings to bed successful to the bore. The obvious symptoms were smoky exhaust, particularly on initial acceleration, elevated oil consumption and fowled plug electrodes. The cheapest solution was to take the vehicle on a high speed journey (several hours - may need to be repeated), driving assertively (no engine  labouring). This often resulted in a miraculous change in the engine - dramatic drop in oil consumption, no smoky exhaust, potential improvements in fuel consumption/power. The alternative, high cost solution, was a engine strip, bore hone, new piston rings and much cleaning of oil residues.


  • Re: Help Please - 912ULS Low differential pressure on Cyls 1 & 4

    by » 4 months ago


    Brian Morris wrote:

    I've only owned it for the last 100 hrs but wouldn't see why the operating parameters I use would have been any different from new.

    It has a CSP and is set at 5700 for takeoff, 5300 for climb and 5100-5250 for cruise.

    So why not up the RPMS for 50 hours: Takeoff 5800 RPM, Climb 5500 RPM & Cruise 5500 RPM ?


  • Re: Help Please - 912ULS Low differential pressure on Cyls 1 & 4

    by » 4 months ago


    When I had high oil consumption on my old engine with new rings I still had good leak-down pressure values. I also suspected that I had glazing of the cylinders that prevented the rings from bedding in. I did inspect the cylinders and although they did not look glazed I did use a deglazing oil to see if it improved the situation, which it did not. I enquired about getting the cylinders re-honed but it is a specialist job with Nikasil linings and none of the local specialists wanted to touch an aero engine.


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