sump oil screen failure
Posted: Wed Nov 29, 2017 11:37 pm
Just a quick note on my findings at the 10 hour oil change yesterday. I do pull the oil screen out to examine for any particles large enough to have a part number on them(ha ha!) and to look at oil itself.The oil looked clear and had no real outstanding particles..some carbon and one or two Al flecks was all. After examining the screen, I noticed that the center section was still in the engine on the pickup tube. The screen is assembled with a rivet in the center, holding the large outer part together with the inner adapter that fits on the pickup tube. That rivet had been loose for a while since the last oilchange, and had wobbled out its hole (why??) and had come loose, or so it looked, probably on the last flight on that load of oil. On that last flight, the oil pressure AGAIN took off for the high end,(above 85psi) (monitored with capillary tube instrument at front hub area) but this time I caught it on down wind approach, and landed (not my best) as quickly as I could. I looked closely and found the initial rivet was much smaller than the hole in the two peices, and was not squashed (set) properly. The wobbled out hole had exceeded the diameter of the set on the rivet. I was concerned as this was an original Aerovee kit component. I did find another source (Beck-Arnley # BA-041-0700, around $9 at ORielys auto parts) and was astonished that the new one was very much better quality and appeared to be more robustly constructed, with a properly set rivet . I got two.
Investigation the oil pressure regulators, I did find particles that appeared to be aluminum making the rear most regulator piston stick again. The front regulator piston didnt appear to have any particles. I repolished them both with scotchbright, cleaned all places I could reach, reassembled with lihium grease, added oil and ran it up for 15 min at varrious rpms. All normal again. What I dont understand just yet is why the regulator pistons appear to only stick at the top,( this is second accurance) and not further down to allow for lower than normal oil pressure?
So, my suggestion to whomever is interested is to take a close look at your screen, and make sure nothing is loose where the revit is. This is what I think, at this time, is the cause of my sticking regulator piston, other than them being quite new and maybe not broken in.
Has anyone else noticed this bad rivet job on the screen? Were there any other problems noted, say with oil pressure regulator sticking? Unexplained aluminum particles in the oil? ( I do realize pistons will shed small particles while they get broken in).
Joe
Investigation the oil pressure regulators, I did find particles that appeared to be aluminum making the rear most regulator piston stick again. The front regulator piston didnt appear to have any particles. I repolished them both with scotchbright, cleaned all places I could reach, reassembled with lihium grease, added oil and ran it up for 15 min at varrious rpms. All normal again. What I dont understand just yet is why the regulator pistons appear to only stick at the top,( this is second accurance) and not further down to allow for lower than normal oil pressure?
So, my suggestion to whomever is interested is to take a close look at your screen, and make sure nothing is loose where the revit is. This is what I think, at this time, is the cause of my sticking regulator piston, other than them being quite new and maybe not broken in.
Has anyone else noticed this bad rivet job on the screen? Were there any other problems noted, say with oil pressure regulator sticking? Unexplained aluminum particles in the oil? ( I do realize pistons will shed small particles while they get broken in).
Joe