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inverted oil

Chipper G

Well Known Member
I am installing the full Raven kit on my IO-360-M1B and I am wondering if I can use the forward left 3/4" safetied plug that goes into the oil pan as my return?
 
I am installing the full Raven kit on my IO-360-M1B and I am wondering if I can use the forward left 3/4" safetied plug that goes into the oil pan as my return?

Perhaps you meant 1/2-14 NPT? Either #6 below will serve as a return from the tank.
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Not a good explanation but . . .

I don't think so, look at that fitting for the return, it is above the oil level when G's are down relative the the pilot, like gravity. When I was installing the 1/2 raven in my M1B, the tank was on the opposite side to the return. Think vertical, and knife edge operation and where the oil will want to go.

When going vertical, if the return was at the back of the engine, the return would become a drain into the tank . . at the front it is not.

I made my own fitting and pressed in the stand pipe (Raven and Christen not available at the time). It is close to the top of the pan so as to be captured and not possible to fall out. I called Raven and it was explained why it was needed.
 
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do you have pics of your install? those #6 fittings are level with the oil screen in normal flight I have the 90* fitting with standpipe in it from raven.
 
Find a copy of the Christen Inverted Oil system manual and follow the recommendations there. I think Dan Horton used a Lycoming diagram to show where Christen recommended the line go.

It has been close to 30-years since I went digging through this stuff. At that time, I had a boss or two welded to my oil sump just in case I wanted to install an inverted oil system.
 
Yes that’s the fitting sir

Ok, both the plugs marked #6 go to the same place. Use the one on the side opposite the tank.

Does your sump have the port with the plug marked #12 in the diagram? If so, did Raven give you an extended pickup tube for it?

EDIT: Poked around in some other parts manuals this AM. Lycoming shows the factory inverted oil sump fittings in the 390A catalog. Same sump as the M1B, illustration below. #16 is the pickup, replacing NPT plug #12. #17 the return, replacing one NPT #6; it can be located on either side. #15 is oil feed to the pump, replacing #19. And the little #13 plug is used with inverted oil only. Its purpose is to block the usual oil path to the pump.
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I made my own fitting and pressed in the stand pipe (Raven and Christen not available at the time). It is close to the top of the pan so as to be captured and not possible to fall out. I called Raven and it was explained why it was needed.

For the curious, the standpipe is needed to prevent total oil loss in the event the breather is blocked. Below I've drawn a red plug in the breather hose, but the most common causes would probably a kink, or a stuck ball valve in the top of the separator can.

In upright flight with the breather blocked, case pressure due to blowby will push oil to the separator can and overboard. In essence, it would act just like a 912 Rotax, which has no breather, and by design uses case pressure to return its oil to an external tank. With a standpipe on the oil return fitting, case pressure can only push sump oil level down to the top of the standpipe, after which the blowby gas exits via the return hose without pushing oil. Enough oil remains in the sump to prevent starvation.
 

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For the curious, the standpipe is needed to prevent total oil loss in the event the breather is blocked. Below I've drawn a red plug in the breather hose, but the most common causes would probably a kink, or a stuck ball valve in the top of the separator can.

In upright flight with the breather blocked, case pressure due to blowby will push oil to the separator can and overboard. In essence, it would act just like a 912 Rotax, which has no breather, and by design uses case pressure to return its oil to an external tank. With a standpipe on the oil return fitting, case pressure can only push sump oil level down to the top of the standpipe, after which the blowby gas exits via the return hose without pushing oil. Enough oil remains in the sump to prevent starvation.

so the #6 gets removed and the fitting with the standpipe gets installed and goes to the bottom of the oil breather can thank you sir
 
just got off the phone with Raven! the #6 is the place for that 90* with the standpipe. I also need the sump install kit that has all of the parts I was missing
 
Hey Chip---you planning on sustained inverted flight I guess?
This is one area that you really dont want to mess with. I know of a pretty new engine that got destroyed by a malfunctioning ball valve and once the plane came back to normal flight the oil pressure went away. Yep====expensive destruction of the bottom end, and some damage by landing it in a field.

If you arent sure, I'd recommend getting one of the aerobatic engine builders to help guide you. Dan's diagrams are fabulous, but you have to make sure all of the system components are functioning as required.

Tom
 
Correct the instructions are clear on the first inverted flight zero pressure is possible. This is why you must recognize the no OP issue and shut the engine off and dead stick it in.
 
For the curious, the standpipe is needed to prevent total oil loss in the event the breather is blocked. Below I've drawn a red plug in the breather hose, but the most common causes would probably a kink, or a stuck ball valve in the top of the separator can. . . . .<snip>

Thanks for that, Dan, it is what the Raven guy said. BTW the stand pipe is pressed into a standard fitting. The press depth is greater than the clearance between the top of the pipe and the "ceiling" of the sump for that fitting. This way it can NOT come loose and depart and play with moving parts.
 
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