My Opinion
Everybody here is right....I think...I am no expert.
Lets face it, our engines are expensive and we want to protect them.
Sometimes things happen and they sit for awhile and were not preserved correctly, time flies.
It seems the main culprit to dry starts is the cam. I personally know of 2 resurrections without major efforts to oil things and a few months later they were making metal from the cam. I am sure it happens more than we know because of the time between restarts and a maintenance issue.
The cam lifter assembly is a steel to steel interface that is kind of spring or pressure loaded for a metal to metal rubbing effect. Most other important engine parts are a close fit that oil is pumped to and lubricate the contact.
The cam lobe / lifter is splash lubed or spray lubed or both depending on engine model. We have been told the first few seconds of a cold or dry start is the hardest on the engine because of lack of oil pressure and flow until the pressure builds and / or the splashing occurs to lube stuff up. I have even heard 1000rpms is better than 600 for this splashing to occur even though faster is more rubbing. This all is occurring in mere seconds at start up. We also know engine builders apply a special mixture of oil and STP or a store bought product to apply to metal surfaces to keep them from rusting and aide in protecting metal parts the initial startup process. Therefore we should or want to protect the cam after the engine had not run for some period of time against the possibility of rust being on the cam/lifter interface and acting like rubbing compound wearing away the smooth surface of the lobe and allowing for accelerated wear of a critical part of the engine. A part that requires a complete disassembly of the FWF-engine if bad!
How to oil it?.......many ways.
Turn engine upside down. If not installed on the plane. I have seen Lycoming's stored on a tire upside down for this very reason.
Spin the prop with a set of plugs removed until your arm hurts, as Jessie says! This is splash lubing the lobes and you do it a lot to be sure they are coated well and it helps build some oil pressure of fill the oil galleries so the oil squirts quicker on the start up.
Some of us with tail draggers can even lift the tail high enough to put a nose down angle on the engine and fill the crankcase up. Yes, it takes approx. 5 gallons. It may create an air bubble at the top but it surely gets the oil closer to the cam and personally I put a hose on the crankcase vent and align vertical and hold a rag over the top as I burp the sump as the pistons move back and forth. This is a 2 person job for sure. I only rotate the prop a dozen or so times like Jessie and feel like all is coated. Then once the tail is safely back on the floor and oil level back to 8qts., I spin the engine with the starter (plugs still out) until I see oil pressure on the gauge, usually 10-12psi. Then it is ready to take out and run.
Yes, I do this every 6 months or so during extended periods(just oil not start)
Yes, I use cheap oil...then use good oil for the start.
Yes, it leaks out intake and exhaust valves, etc. Makes a mess.
Yes, you have to clean the plugs, maybe twice.
Yes, this lifting process is all but impossible on an A model. But filling to coat the internals and get the oil closer to the cam can not hurt.
Personally I feel really good about this process and that I am doing all I can to protect the insides of the engine. I may be over doing it, time will tell.
Most of you guys know all this but posting for archives and newbies!
And I will repeat my opening line. I am not an expert!