Here's one for the gurus in the group...
So I have a 71 Cherokee 140 (but the s/n starts with 72...), 150 horse E3D. Factory air was STC-ed out long before I purchased the plane. I use about 1 quart of Aeroshell 15W-50 with Camguard every 9 to 10 hours. Otherwise, about 2550 since major, with at least 2/perhaps 3 cylinders replaced (#2 just this spring). When I change oil, I fill to 7 plus Camguard, use to 6, and add. I am one of those old geezers who uses a pinch of Marvel Mystery Oil in the fuel tanks when I get my 100LL fix.
I know the lower air scoop, pilot's side, is to supply cooling air, via SCAT tubing, to the gascolator. All hooked up correctly.
So why am I getting the standard oil film streaming out of the front of the gascolator air scoop? It is as though the air pressure at the inlet/front of the scoop is lower than the air pressure inside the lower cowl (which should be lower than in the upper cowl, most definitely). I've not measured how far down my crankcase breather pipe downtube extends. Could that be a factor? The gascolator chamber is clean and oil-free. I can't say I have yet checked the inside of the new SCAT tubing to see if it is oil-coated. The baffle material looks like it is making good contact with the lower cowl.
So, I'm a bit baffled. All the other 140s on the field are clean around the fronts of their scoop inlets. The air pressure at the inlet should be higher than the air pressure at the crankcase downtube area. Any ideas?
So I have a 71 Cherokee 140 (but the s/n starts with 72...), 150 horse E3D. Factory air was STC-ed out long before I purchased the plane. I use about 1 quart of Aeroshell 15W-50 with Camguard every 9 to 10 hours. Otherwise, about 2550 since major, with at least 2/perhaps 3 cylinders replaced (#2 just this spring). When I change oil, I fill to 7 plus Camguard, use to 6, and add. I am one of those old geezers who uses a pinch of Marvel Mystery Oil in the fuel tanks when I get my 100LL fix.
I know the lower air scoop, pilot's side, is to supply cooling air, via SCAT tubing, to the gascolator. All hooked up correctly.
So why am I getting the standard oil film streaming out of the front of the gascolator air scoop? It is as though the air pressure at the inlet/front of the scoop is lower than the air pressure inside the lower cowl (which should be lower than in the upper cowl, most definitely). I've not measured how far down my crankcase breather pipe downtube extends. Could that be a factor? The gascolator chamber is clean and oil-free. I can't say I have yet checked the inside of the new SCAT tubing to see if it is oil-coated. The baffle material looks like it is making good contact with the lower cowl.
So, I'm a bit baffled. All the other 140s on the field are clean around the fronts of their scoop inlets. The air pressure at the inlet should be higher than the air pressure at the crankcase downtube area. Any ideas?
