Engine preservation to prevent corrosion during extended non use (and ground running?)

Stickandrudderman wrote:
The one thing I have done periodically is turn the prop

THAT is a BAD thing to do, despite that many believe the contrary.

Here’s why: Every time you rotate the prop you are rotating the camshaft as well and the cam followers wipe the oil off the face of the cam lobes. When there’s no more oil film on the camshaft or followers they will start to rust.

Does Lycoming says something somewhere about rusting valve springs? Or engine corrosion in general?

TomTom wrote:

Does Lycoming says something somewhere about rusting valve springs? Or engine corrosion in general?

I refer to Textron Lycoming Operator`s Manual 1987, Current Revision 1999. Nothing about it is written.
No engine manufactuers would mention the possibility of rusting.

Michael wrote:

The one thing I have done periodically is turn the prop

THAT is a BAD thing to do, despite that many believe the contrary.

With what little knowledge I have gathered, I should think that over seven months of inactivity there would not be much of an oil film left on the cam shaft and lobes?
Also, when hand turning the prop, doesn’t one also operate the oil pump? Bringing some oil up, to at least replace what dripped down? But it might well be that turning the prop just a little bit is little good, and might even do some bad – if one does, it might be well to do a good many turns, to get at least a beginning of a flow in the cold thick oil.

Admitting it is a very different engine, I will almost religiously turn the prop on my Rotax 912 for some five turns or so before cold starting it – with the express intention of distributing a bit of oil here and there. ‘En passant’ producing the trademark “burp”, locally known as “flushing the loo”

I tend to agree there isn’t enough experiemental evidence to make this case one way or the other.

What is definite – from the engine design – is that turning the engine over isn’t going to put any oil onto the camshaft, and that is the bit of the engine which gets most often hammered by corrosion.

However in this specific case the corrosion on the springs is evidence only of corrosion on the springs. Given that the springs must have been clean 35 hours beforehand (unless the engine rebuilder was a crook and put old ones back in – that does happen and I know of one firm who used to do that, and other things) it’s likely there is corrosion elsewhere. But you won’t establish that without further dismantling.

Sticksndrudderman did you consider using an engine dehumidifier during this period?

https://www.euroga.org/forums/maintenance-avionics/2043-engine-dehydrator

I made my own using an aquarium air pump and a bottle of silica gel when my aircraft was down for a few months awaiting a new spinner backplate…

turning the engine over isn’t going to put any oil onto the camshaft

Excuse me, I must be clean daft obviously, but how then does the camshaft ever get any lubrification, if not by the engine’s turning?

Jan wrote:

Excuse me, I must be clean daft obviously, but how then does the camshaft ever get any lubrication, if not by the engine’s turning?

In a Lycoming the cam and followers rely on splash lubrication…one of the reasons to idle at 1000-1200 rpm and not lower…

Thanks Anthony, there’s no end to learning, and to wonders. Really a different kind of engine, obviously, and I can’t help wondering about the high reliability figures from such a primitive concept. I reckon the low rpm figures must help to make a certain degree of maltreatment bearable. Compared to the 912, that is.