I’ve not written about why I have sourced and fitted another Jabiru 2200 but I had a slight issue with my previous … it dropped a valve seat and then had an unexplained issue with a piston which decided to dismantle itself
Slight problem was we were 2 up, Will was in his second only time in the rear (as part of my training to get him to soloing) and we were 1,100’ N of the field
The wind was between 5-8 Southerly and so an immediate turn back .. with almost zero power but a still running engine was initiated ..throttling back to try to analyse the issue
We both calmly discussed the issue … Will initially saying ‘Your aircraft’ … having already made the turn for home within seconds of the first rough running
I had Wills work bag on my lap in the front .. so space was at a premium and I certainly couldn’t hold the stick and throttle and fly with the bag … so elected to hand back to Will and govern throttle and course whilst he flew
We ran through the guage readings as we inexorably descended, now downwind, back towards an impossible to reach threshold.
Having exhausted options as to what was wrong … fuel, mags, switches, nothing … I advised to tighten the harness straps right up as we would probably not make the field
A minute or so passed and almost impossibly the very shallow float angle and supreme lift ..and it looked like we had a great chance of just making the field
Will held off to perform an almost perfect 3 pointer … and I advised to kill the mags … the ‘plane rolled to a silent stop a few feet into the upwind end of the runway we had just departed from
Engine was inspected as it cooled and removed that afternoon to drive up to Yorkshire for tests
As the rebuild ..new valve seat, new piston, liner, rings, valve, push rod and Conrod was going to take a while I sourced the spare .. all the way from Shetland
Jersey Sherwood Ranger 
Hi David, first of all, top marks to both you and Will for calmly handling the situation, not easy to do when the gremlins arrive uninvited at the door.
With regards the self destructing piston, was it in the same bore as the displaced valve seat, if so, it most likely held the valve down low enough for the piston to strike it, the valve being offset from the centre of the piston would cause it to flip sideways in the bore, resulting in a destroyed piston.
Not knowing the construction methods employed on the Jabiru, the valve guides may be either screwed in and peened to prevent rotation, or, most commonly, simply pressed in with an interference fit, if the latter, then it will definitely need a new cylinder head.
I personally would recommend checking the crankcase, rods and crankshaft for any distortion and or cracking, but as the engine remained running after said event, I feel that you may well be lucky in that respect.
Kind Regards
Nigel