Bill,
The angled adapter is definitely the way to go. It fits the mount for 320's and 360's from Van's for an RV-9. If it won't fit the O-290 mount then we can install a spacer between the adapter and the engine that moves the filter aft, giving more clearance to the diagonal mount support structures. The oil filter used with this angled adapter, unlike the filter used with the rear-facing adapter, has a bypass valve built into it that prevents the oil in the filter from draining while removing the filter. The key is to turn the filter upright, as soon as the filters mounting stud is separated from the oil filter adapter.
If done properly you spill maybe two ounces of oil from the filter, in fact that would be a lot. Placing a rag or towel under the adapter will catch any oil that is spilt and keep the rest of the nacelle clean. It is a way cleaner setup then the adapter that points the filter to the rear which lets the filter drain in its entirety, all over the engine and nacelle, while you are unscrewing the filter from the adapter.
Of course if that is all that will fit, the rear facing filter is still better then just the pressure screen and removing that filter isn't much messier the removing the oil screen housing to service the screen at oil change time.
BTW using a small kitchen trash bar wrapped around the rear facing oil filter adapter and filter, while removing the oil filter, will help with the mess a bit, by catching alot of the spilled oil in the bag.
Good Luck,
Mahlon
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