Due to a progressive loss of compression,(low leak downs) in my Generation 2 Jabiru 2200 with increasing oil consumption (pumping it into the overflow bottle), I suspected jammed rings, after nearly nine years and 450 hours of trouble free operation . The engine has been operated on Avgas exclusively and, apart from its running in period using Shell 100, has had oil changes of Aeroshell 15/50 at 25 hours max.,often very much less. The aircraft, a J160, was built by me and only ever been flown and maintained by me, giving faultless service since new. A top end strip down was done a month ago, confirming jammed rings, some worse than others. All valves were in excellent condition, sealing perfectly and showing no signs of stress due to poor heat transfer. They could well have been returned to service ! The barrels were honed, new valve relief pistons, rings etc. were fitted along with new valves, washers, inner and outer valve springs, rocker bushes (the engine had the old drip lubrication, which I decided to stick with, rather than converting to the hollow push rods.) During an oil change I always open the rocker chambers to ensure adequate lubrication, always giving the springs and rocker bushes a squirt of oil, just to be sure. The old bushes showed minimal wear. Interestingly, the barrels showed no signs of rust, surprising since the aircraft has spent its entire life hangared about 3 nm. from the Victorian coast, with those cold moisture laden Southerlies in Winter. I have always placed covers on both the exhaust and air inlet after shutdown . 'Nordlock' washers were installed on the flywheel bolts along with modified through bolts. After 10 hours the engine is performing well, oil consumption Is minimal, pressures and temps well within operating limits. Nearly all the running- in so far has been achieved with circuits. Total cost of parts amounted to $1700 ...... Bob