Peter wrote:
In the absence of oil analysis, it won’t be possible to prove when the rust happened.
OA would not have picked this up. Besides, with just 35 hours on the clock SMOH there would have only been 1 maybe two, no good baseline from which you could derive much from.
As always, OA provides lot’s of largely useless data…
BTW: Corrosion on AC piston engines is like fleas on dogs: they all have some.
Corrosion on AC piston engines is like fleas on dogs: they all have some.
Sure; what I was getting at is that if corrosion is found when an engine is opened up, can you ignore it and put it back together again?
I agree about OA at 35hrs; I missed that bit. Still, a corroding engine will chuck a lot of Fe into the oil. As regards OA generally, well I guess attitude to risk depends on whether you fly over mountains, etc.
Peter wrote:
As regards OA generally, well I guess attitude to risk depends on whether you fly over mountains, etc.
As usual, we disagree on the usefulness of OA.
I M H O , there is little to zero ACTIONABLE information in OA .
The point being, that if you want to lower your risk of engine failure, you’re better off putting your time & money in other more reliable preventative maintenance tasks.
Re: Risk & Management and the usefulness of OA – I could build a case where relying on OA might ADD risk not diminish it :
Think of our intrepid owner/pilot that relies heavily on OA as a gauge of his engine’s health and forgoes inspecting the oil filter AND oil screen during a regular oil change and missing the chunk of broken piston skirt lodged in the screen.
OA wouldn’t have showed a nary of an imminent failure.
Think of our intrepid owner/pilot that relies heavily on OA as a gauge of his engine’s health and forgoes inspecting the oil filter AND oil screen during a regular oil change and missing the chunk of broken piston skirt lodged in the screen.
He is an idiot.
There will always be somebody.
OA is useful as a tool in a toolkit e.g. a bearing with poor lubrication, maybe close to seizing up, will generate no large particles initially but will show up in OA.
Peter wrote:
a bearing with poor lubrication, maybe close to seizing up, will generate no large particles initially but will show up in OA.
I don’t think so.
Imminent bearing failure depends on the cause and typically is due to a loss of oil pressure and in that case there would be NO warning from OA or anything else for that matter.
If indeed, in the extremely rare case that the bearings were simply wearing out, you would have been seeing the higher metal readings for many 100s of hours and probably not acting on it since it would not have been considered conclusive enough to tear down the engine. Most would carry on until the oil pressure starts to weaken which could be 100s of hours before any failure.
Michael wrote:
The point being, that if you want to lower your risk of engine failure, you’re better off putting your time & money in other more reliable preventative maintenance tasks.
I’ll disagree with that, after all, it was proven during WW2 that preventative maintenance was the cause for failures due to either infant mortality in the replaced parts or due to MIFs….
Unless of course, the maintenance follows guidance dependant on wear and usage and not an arbitrary number of flight hours……
On the OP topic: the thing I would check is whether there is corrosion on the camshaft. On a Lyco (IF this is a Lyco) the camshaft is the weakest link because it gets poor lubrication, and corrosion on it quickly destroys it and other bits. Unfortunately I doubt the camshaft can be inspected on your engine without removing at least one cylinder.
Stickandrudderman wrote:
The one thing I have done periodically is turn the prop
You did what?
I would like to know if CAMGUARD could have prevented this.
I passed this thread to the CG developer.
I use Camguard. It incidentally roughly halved the wear of the ferrous metals.
