History: the aircraft was purchased from Leaseair PTY LTD by me at 1318.0 ( post through bolt failure).
Prior to my ownership the engine was sent back to the factory at 1100 TTIS ( 15/08/10 for a top end overhaul due low compression and TBO, on its return and after install and runin it was fine, up until 1200.8 (100.8 TTSO) when it was noted to be weeping oil around the base of the barrels and the orange sealant used on either side of the shims was peeling away.
A call was placed to Jabiru (Don I think, called me chief) who informed that it is not U/S pending a successful torque check of the through bolts, which showed nil movement.
I was informed that the cylinders could be lifted and more orange sealant applied if it was bothering me I noted that it was just a clean up issue to the owner and it was elected to put up with the weeping.
At 1314.6 TTIS (214.6 TTSO) a pilot annotated that it did not make minimum static rpm (As per POH) so after the usual checks the carburettor was removed and serviced with corrosion under the bellows being found, this was discussed again with the factory the corrosion treated and the jetting checked, post reinstall it would still not make static RPM and I was advised that it is fine and that the factory was releasing an amendment to this requirement.
At 1318.0 (218.0 TTSO) the engine suffered an inflight through bolt failure of number 2 Cyl and was put down in a paddock, subsequent investigation revealed that The SB for the through bolt nuts had not been carried out and the time to comply had just expired 29/04/12.
Prior to release of this SB the through bolts were discussed with the factory ( the engine had only just been installed, post Top end at the time of the weeping problems) and the advice was that all engines would be done whenever they were returned for major service and not to worry about it.
So leasair elected to leave it as is and no reference was made to the SB again until after the failure! our mistake!!!
Post failure the engine was inspected, repaired, new T/Bolts, new #2 piston and cylinder, heads visually checked re-lapped and engine run in.
At 1351.2 TTIS (251.2 TTSO) number 2 Cylinder exhaust valve was leaking past the seat, the head was removed and it was noted that there was cracking and pitting around both inlet and exhaust seats so it was rejected and a new head purchased and installed.
A bore scope revealed none of the same on the other cylinder heads...
At 1475.6 TTIS (375.6 TTSO) the engine dropped an exhaust valve seat whilst sitting at idle prior to takeoff on first flight of the day, luckily the seat wedged sideways and was retained buy the valve sticking open and slightly impacting the top of the piston.
Upon disassembly (see pictures) the other two older heads show signs of the valve seats moving, the engine has never been over temped the heads show no abnormal signs of cylinder creep, it has CHT and EGT on each cylinder and the dynon EMS log showed it has always been within limits.
Other things noticed on disassembly:
1. locating dowel under the distributor drive shaft was not installed correctly and was eating into the shaft slightly.
2. Sump had a 2 inch piece of cylinder O-ring rubber sitting at the bottom and the usual carbon, a few pieces of metal.
3. the sump flange had a ding in it at the same location that it used to weep ever so slightly.
4. #4 cylinder head intake runner has a crack forming down the face of the valve boss.
5. lots of excess flange sealant inside the engine.