G'Day Nightmare , my engine ( 2200 No.2787 ) in my J160, has given trouble free operation for nearly 10 years now. It has run exclusively on Avgas, and the heads have never been removed ( about 430 hours). I do fairly regular Leak down testing, and swing the prop through about 12 blades before every flight. I do oil changes around every 25 hours, sometimes more frequently, and replace the spark plugs, set at .023", after every 50 hours. My CHT's with an ambient temp of around 23oC, (at MTOW and S&L),are around 130oC ,except for No1which runs considerably lower. I am the sole pilot and ensure proper run up checks are done prior to each take-off ( ie. 2200 rpm,as recommended ) and have a climb-out fuel flow of around 32 l/hr (depending on atmospheric conditions), with around 17 l/hr S&L @ 2850 rpm. I would expect that the fuel flow figures with the smaller Jab( at MTOW)to be a little lower. With proper operation your engine should give similar service and reliability ...... Bob :cheers:o