Peter wrote:
Catastrophic engine failures are indeed very rare, but when they happen they are often like this. Timothy can tell some stories. I once saw a Bonanza (TIO550?) arrive in “my” hangar with the crankcases having various parts (mostly conrods) sticking out through them; that engine just had an overhaul by some UK shop. There is a lot of power and a lot of inertia and the crankcases are only ~5mm thick aluminium castings which you could go straight through with a single blow of a hammer.Most of it is probably defective workmanship e.g. grossly wrong torque on cylinder bolts.
… which would mean, that the proverbial harmless cylinder pull (for inspection, for replacement, for honing ) is by far not as harmless as it seems. One should carefully consider whether “just pulling a cylinder” is worth the risk. Just a thought based on Peter’s argument.
It is indeed a risk if done by somebody stupid.
If done with a freshly calibrated torque wrench, bolts torqued in the specified order, etc, then there is no reason why the engine should blow up. Otherwise, new engines and overhauled engines would be blowing up all over the place.
Everything between 1 cylinder changed and all 6 changed is something that’s done on a daily basis, even in Europe. Most of these don’t blow up.
Nearly all turbo engines don’t make 2k hrs. Most have a “top overhaul” before 1k. Most of these don’t blow up afterwards.
Unfortunately there is a certain % of monkeys in that business (as there is in all of aircraft maintenance, including avionics) and they don’t do it right. Some are extraordinarily stupid – like the case of a motorcycle lube in my elevator trim, which froze at FL140.
I am happy about my cylinder having been pulled. I was there, watching the process and checking it.
You cannot fix a sticky valve properly with the old rope trick, because you can’t re-hone the seat. All you can do is shove a reamer down (most of the length of) the valve guide, or a load of grinding paste and use a drill to rotate the valve to clean up the guide or the valve seat. It is a temporary fix. Then you hope you got all the paste out 
What the solution is, I don’t know. Nearly all companies in Europe have a “variable” name when you ask customers privately – including some which have a fanatical reputation. A lot of US ones are also bad. But one can find US firms with a really solid reputation, and I think Peter has done the right thing by getting a fresh engine from the US.
highflyer wrote:
OK, I have never seen such pictures before. Let`s imagine this happens over the alps, that`s scary.
I do no want to sound like thinking no end of myself. But you should not cross the Alps in a Single without having gotten proper mountain training. A single can be safely landed engine-out in the mountains (I wouldn’t bet for a twin with that glide ratio). Flight schools in Bavaria and FI/s offer training to this end. It’s fun, it’s useful, … and of course it cannot save your life when the fog goes down all the way into the valleys ;)
It depends on where.
The Alps, say FL160+, have a probably 90% chance of gliding into a flat bottomed canyon. In case of cloud below, you need a GPS running a topo map.
The Pyrenees, that’s different on one flight I saw maybe 30 mins with absolutely zero options… a prob99 death.
AJ wrote:
which would mean, that the proverbial harmless cylinder pull (for inspection, for replacement, for honing ) is by far not as harmless as it seems
It isn’t, cylinder work is some of the highest risk work on an engine. That’s not to say it’s dangerous (as Peter pointed out, cylinder work goes on all the time, and engines only rarely blow up), but in terms of jobs that can be done on your engine during its life, it has one of the highest likelyhoods of resulting in expensive damage or engine failure. Removal of cylinders should only be done if really necessary and by someone who knows what they are doing and with the proper tools following the correct procedure.
Never consider “pulling a cylinder” as harmless.
Some news about the repair of the plane. All the planning was to have the plane ready for the checkride on the 5th of December. But the following happened:
The propeller wasn‘t send back after the overhauling in time (although they should have delivered it 2 weeks earlier). So we decided that I will get the plane back next Tuesday. There is a little chance, that it will be ready then. A little chance only, because during the installation some missing parts where discovered, they have still been with the SUST, and they were send via Post and with delay to the maintenance. All this, just to find out, that the magnetic pickup for the RPM is missing and that a different adaptor is needed to connect the RPM axis. The old adaptor isn‘t working.
So at the moment my feeling is, that Tuesday is illusory but I still hope to be ready before Christmas.
Brilliant to see you working on getting back in the air so quickly, Peter. It’s absolutely the right way to do it.
You will probably spend as much on extra avgas bedding in the new engine as you will pay for the engine
You will probably spend as much on extra avgas bedding in the new engine as you will pay for the engine
Don‘t make me worry Peter! 
I will certainly spend more on extra avgas than the £700 I spent on the cylinder repair.
I suspect quite a lot of people would not have had the cylinder re-honed, and objectively I am not sure whether a re-hone at only ~400hrs does anything useful. One would fit new piston rings for sure…
