This is perhaps the most significant change in the conversion of the engine from a horizontal airplane engine to a vertical helicopter engine. The original oil pan was removed at the Lycoming factory, and now it needs to be replaced by an aluminum plate with an oil circulation connection at the bottom. Eventually, a replacement oil sump will be installed at the bottom of the engine.
The lower bolts screw directly into the engine block, and the upper two-thirds are through bolts with lock washers. The lower bolts will need to be wire tied together.
The lower hole for the oil circulation needs to be centered and resized to match the gasket and the fitting. It’s a plumbing fitting that has a tapered thread and required a tapered tap, which I didn’t have and had to special order.
Instead of trying to re-drill the offset hole, I decided to file the hole until it was centered then upsize the hole one bit at a time.
The threading of the hole was challenging because since the hole is a tapered thread, and if it’s threaded too long or too short, the fitting won’t be angled at 7:00 o’clock as required. In addition, the fitting can’t protrude through the plate, so it will need to be sized just short of reaching the engine.
