47U Posted February 12, 2023 Report Posted February 12, 2023 Location reference… the tube is the oil dipstick and the #3 cylinder rear baffle, O-360-A1D. I was looking for the source of a small oil leak (you can see it accumulated on the baffle) and noticed this threaded boss in the crankcase. Looks to be 1/4” course threads. I looked through the Lycoming parts book but didn’t find anything. Ideas? Anyone? Oh, the oil leak was a rocker box oil drain tube… all good now.
RLCarter Posted February 12, 2023 Report Posted February 12, 2023 Really surprised no one has replied, so here’s my 0.03¢ (inflation) Hard to tell from your photo…. It looks like it’s plugged off? It’s common in manufacturing to have a plugged hole from a cross drilling operation but they are generally NPT (National Pipe Thread) and an 1/8” NPT is fine thread. It could used on a different variant within that engine family and/or a different aircraft. I’d find another “C” of the same vintage and look to see if anything is attached there 1
Raymond J1 Posted February 12, 2023 Report Posted February 12, 2023 (edited) This tapped hole is present on many cranckcases, it measures 1" deep, made to receive a 1/4 x 3/8" screw. Used for fixing the rear cooling baffle by some, it is not used on Mooney. Edited February 12, 2023 by Raymond J1 2
Guest Posted February 12, 2023 Report Posted February 12, 2023 10 minutes ago, Raymond J1 said: This tapped hole is present on many cranckcases, it measures 1" deep, made to receive a 1/4 x 3/8" screw. Used for fixing the rear cooling baffle by some, it is not used on Mooney. Exactly what it is, a baffle attachment point.
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