To Turn, Or Not To Turn....... That Is The Question !

[mike newall]

Advice from wise old sage Engineers and engine builders always said, once inhibited, do not turn the engine until it comes into service.

The Lycoming SI1481B suggests otherwise, however this is for relatively short term service. Our IO-540 was inhibited at the overhaulers as IRAN overhaul and has desiccator plugs in that are rejuvenated every 3 months. It has been there for a year.

I pull the pin and roll the grenade......

Turn or don't turn - Pro's and con's of each please

 

[rv8ch]

Block all the holes, totally fill the engine with oil, keep the engine in a place with less than 40% humidity, use desiccant plugs, and then you can turn the engine as much as you want (or can). If you can put the engine on an engine stand, which rotates, then you can just keep rotating the entire engine to keep oil on the camshaft and lifters. If you are in the last few weeks/months of installing an engine, then the main thing is to keep it dry inside. Use an engine dryer, and the engine won't rust inside. More oil won't hurt, but it's hard to get oil on the camshaft without rotating the engine, so low humidity is your friend. Buy a black max or drybot or build a home-brew dryer using aquarium air pumps and desiccant.

 

[PilotjohnS]

Sorry to disagree. I would follow Lycomings advice. Once the engine is preserved, I would not turn the engine over until a few weeks before start. I believe the issue is the combustion chamber area of the cylinders. Lycoming says to fog these with oil during the preservation process. If one sub sequentially turns the engine over, I think Lycoming recommends to re fog the cylinders. In my view the problem is the cylinder walls that are exposed have no oil fog on them. JMHO

 

[Freemasm]

The old "conventional" wisdom was to turn the prop x # turns every y days for engines that weren't being run enough. That was to spread out the exposure related to open valves. I'd follow the OEMs advice and not turn anything. This was changed, I believe, to avoid removing preservative from components that have sliding contact i.e. the cam shaft/followers (cylinder walls previously mentioned). Having observed the delay in OP rise when turning an engine with the starter (no comp/plugs out), I doubt hand turning will do anything as far as distributing oil goes. Without sufficient flow (from engine rpms) to develop system backpressure, it will "least resistance" its way back to the sump before ever moving any oil to the further reaches/passages of the oil system. My worthless $0.02.

Dessicant is cheap. For a PP that has never made water, a passive system should be fine.

One data point =

https://vansairforce.net/threads/en...fully-effective-apporach.207573/#post-1616595

 

[[email protected]]

The real question is "Where are you storing this engine?"
If it is in a happy location. I.E in your house or dry shop or ???wet hangar?????
I have an engine that was overhauled, ran for 4.2 hours then removed for the aircraft and stored next to a furnace in a vertical position for 10 years, then purchased by me 15 years ago and kept in a dry insulated shop.
I looked inside and borescoped the front of the cam after removing the sump and cylinders a few months ago.
The plugs ore out, sump off and there is no oil in the engine
ZERO rust or anything else going on.
Now before I ever fire this engine up it will be flooded with oil for sure to lube it all up.
It has never been stored outside or in a moist area.
I know there is a lot of hand ringing over storing engines and rightfully so. These little engines are very expensive
It all comes down to how you are storing it????
My luck varies Fixit