Problem purging 912UL oil system

Roger Lee wrote:

You can purge with the plugs in or out. I've seen it done both ways. So long as the return hose is hanging in the downward position oil should drool out. If the plugs are in it will pressure the oil out the case. I think the problem is you said you're using a foot pump? If so you need to use a compressor and try 10 psi with some volume vs your 5 psi. Volume here is more a key than pressure by itself. You can use between 5-15 psi. If you leave the plugs in you rotate the prop slower because of the pressure in the cylinders. If they are out I'll rotate at a rate of 90 revolutions per minute. Then since I'm old I call 911 and get some Oxygen before I rotate one more minute. :P :lol:
The oil pump is a positive pressure rotary pump and so long as something is pushing oil in (your air pressure) and the carnk is turning (rotating the prop) then oil gets moved through the system.
I usually see 50-55 psi on the oil pressure guage in the cockpit. Since I'm paranoid of having a bad purge I do a purge twice. Cheap insurance for just 1-2 minutes of work. Sometimes oil comes out and sometimes not, but it has always been good. Check your tappets under the valve cover like it shows in the video. If you do this purge a couple of times and get no oil then start the engine normally. You should have oil pressure immediately. Let it run a few minutes then shut it down and check the oil level.

p.s.
When you do a purge have a little extra oil in the tank so as the oil fills the hoses and the like the oil level in the tank won't get too low and possibly inject air.

Roger can you clarify which steps of the purge you repeat a second time? I’m guessing not the valve tappet check and just the pressurization of the oil? Thanks as always 

I just spun the prop 80-90 fast revolutions two seperate times. So I spin it 80-90 revolutions in about 90 seconds or so. Then I turn off the air pressure and raise the hose up so not to lose any oil. After a 1-2 minute break I do it all over again. So I have rotated the prop 160 - 180 revolutions which only took a few minutes. Since I started doing this 20 years ago I have never had a soft valve and as you spin the prop I can see 50-55 oil pressure during the revolutions.

It seems to work well.