Update: Pictures of the cylinder as removed are shown below. (The engineer removed the cylinder because lap or overhaul or replace, the original needs to be removed. Fair enough.)
The cylinder apparently no longer has any hone (cross-hatching) for the swept part of the cylinder.
Comments please.
Howard.
As you say, he knows engines and he is very knowledgeable. He was Continental’s rep. to Europe Middle east and I think Africa too but not sure. I would have followed his recommendation.
Ben, I have agreed today to fit a brand new cylinder… Nevertheless, I’d like to hear comments from the knowledgeable people here as to why my plane’s cylinder number 5 looks like it does.
H
Howard wrote:
Comments please.
I suggest natural kettle-cleaning method with vinegar 
Did you figure out if it is from temperature overheat or wrong positioning of the valve?
Which of the valves has been found to be leaking?
Can anyone see anything obviously wrong with that cylinder?
problem moved from exhaust valve to glazed cylinder.. One other Q is it common to mix sparkplug types?
I regularly borescope my engine so this is an excellent case study where I can learn more
So is the issue a piston ring not the cylinder? – Also as we know low compression does not affect power, was it too early to pull this cylinder off?
I’m no expert so any feedback to explain where I have gone wrong on my analysis welcome.
That’s why I asked “Can anyone see anything obviously wrong with that cylinder?”.
Not sure if any good engine builders read EuroGA. I used to know a good one but sadly he became ill…
Morning @Howard
When you said “he did something with oil”, perhaps he poured some oil through the top spark plug and when he performed the air test for the second time, this provided a temporary seal?
If I were you, if it’s not too late I’d hang onto that cylinder (even for future use) as I am guessing the real issue might be a gummed up piston ring, This will be “cured” when the cylinder comes off. Putting the old cylinder back on (perhaps with a couple of new valves) would save having to run in the new cylinder.
Is there a way to cancel the new cylinder? As I said, I might well be completely wrong, I am not that experienced and I’m only looking at photos, but that’s my hunch.
By the way, on the bright side, you mentioned you have an old engine. This is a fantastic opportunity to inspect the camshaft and followers. What is it like? There is no reason that your engine can’t go on for years if the cam is in good condition.
So, to answer Peter’s question, in an earlier message on this thread I explained that the exhaust valve is the source of the pressure leak. It’s leaking a lot. Can it be lapped? I’m told not because it’s too far gone and anyway the cylinder has lost its cross-hatching… I’m an accountant (albeit with a science background) not an engineer.
The good news is that the people looking after my plane have told me how pleasantly surprised they are by the condition of the bottom end of the engine. The cams are in excellent condition, so a big money engine repair seems unlikely for a good few years. I do now and have for two years used Camguard. I have no idea if that is correlated with the good condition of the cams.
New cylinder is on its way…I’d love to know more about whether that was the only possible good decision, but the people looking after my plane think so, and it’s certainly a safe decision.
H
