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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Yes that’s the fitting sir
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.
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>