Zzz's post about pickling an engine made me think about when it comes back into service.
Or a fresh overhaul.

Do people normally pre-oil the system or just fire it up and rely on the assembly lube?

I came across a video of a pressure pre-oiler to make sure everything inside is wet.
https://www.youtube.com/watch?v=thfTnYdeNz8

Easy enough to make and plumb into the oil pressure fitting.

Thoughts?

I have not done it yet, but I would absolutely prime the oil system before firing. I'd find a way to pre-lube the cylinder walls too.

There's this from Lycoming: https://www.lycoming.com/sites/default/ ... 0Start.pdf

Pre oiling would be good. I've seen taking out a set of sparkplugs and pulling it through by hand quickly and you can get oil pressure with little stress on the bearings.

You can just pull the plugs and spin it with the starter before you put the prop on. Very easy on the starter/battery and if all is right oil pressure will come right up.
DENNY
Edit: You could also do it with the prop on, engine will just turn over slower.

I couldn’t bring myself to just spin it with the starter. It’s going to take a second for the pump to prime, fill the galleys and built pressure. I was unwilling to put that kind of wear potential on the bearings even though I throughly costed them during assembly. Plus Aero shell 100 isn’t all that great if an assembly lube. Then there is the cam/lifter break in that is never talked about in the aircraft world. Cranking the engine over to pre-lube the oil just wiped off all the cam lube...

We used a drill powered pump hooked into the oil pressure port with a tee. Brought the pressure up to 50psi (which took a surprisingly long time) and held it there for about a minute. Then we rolled the plane out and fired it up. Instant oil pressure.

Nothing wrong with a external pressure lube, I would use the setup if I had one handy, but once you start flying all you have on the bearing is the oil from the last flight a lot thinner then that assembly lube and once a cylinder fires (one - two blades) You are going to have a lot more pressure on the bearings than just spinning with the plugs pulled.
DENNY

We had a few different setups at the overhaul shop. We did a LOT of preoiling! The simplest was an old pressure cooker that we'd pump heated oil through with air pressure, into the oil galley in the nose of the engine at the final stage of assembly. We'd pull the top rocker cover off and when we got oil flow up there, we knew we had oil everywhere. We also drained it as it was pumped. On our test cell, we had a pump that would circulate oil at about 50-75 psi and we would usually run that for a minute or so before rotating the engine. I never was much of a fan of rotating the prop through while waiting for oil flow, for many of the same reasons Whee has mentioned.
John

NAPA stores and probably others sell a rig that is made for flushing out air conditioning lines. It is about a 1 quart pressure container with a hose assembly with an air pistol type valve at the end. Squirter valve has a tapered rubber end for sealing to various sizes. Standard schrader valve for pressurizing the container. You can remove the oil gallery plug that's easiest to get to. Fill the container with lube of your choice, pressurize and squirt. Probably takes a repeat, as the oil filter holds a lot.