RE:  Oil pump priming after oil change; oil pressure

     To follow up on the problem of my oil pump not picking up after an oil change, and having no oil pressure, I seem to have gotten to the bottom of the problem.  Unfortunately, to get the oil pump housing off over the long studs, the engine has to be partly pulled -- mounting bolts removed, exhaust headers removed (to clear the engine mount), and various stuff loosened or unhooked.  Quite a job!
   Upon inspection, there did not seem to be anything wrong with the pump itself, but there were several large-ish chunks of metal where they shouldn't have been.  There's a sort of pocket in the oil pump housing, forward of the oil pressure regulator.  The regulator consists of a piston that seats on a face machined in the housing, and has a spring whose tension can be adjusted by turning the screw shaft that sticks out the back of it.  It's the one with no head on it, but about a 1/8" hole drilled through it.  (Who thought of that?)  Anyway, these metal chunks, on close examination, appeared to be either drill cuttings or machine turnings -- stuff not properly cleaned out of the engine before assembly.  Thankfully, they did not appear to be abnormal wear material.  Tells you that Performance Engines did a sloppy job cleaning the case before assembly.  At least one of these chunks was stuck between the pressure regulator seat and the piston.  This would make the regulator function poorly, if at all, which matches the odd oil pressures I'd been seeing.  It might also make it hard for a fully drained pump to prime itself.  Some pumps are funny, in that they seem to need some back-pressure to prime properly.
   I've cleaned and re-assembled the oil pump, using the sealants and silk thread called out in SIL99-2B.  Thanks to the folks at Dart Aircraft, in Waco, TX, for finding all that odd stuff and getting it to me overnight!  You need Permatex 3D on one face, Loctite 515 on the other face, and a carefully laid silk thread to make the seal.
   When I filled the engine after the oil change the other day, I only put oil in to bring it to the 11 qt mark.  This time I brought it all the way to 12, and also poured a little oil into the filter holder.  If you turn the prop backwards slowly, it draws that oil down into the pump to help seal the vanes and prime it.  This time, on start-up, I had oil pressure almost immediately.  Problem now is that it's too high.  I've backed the oil pressure regulator screw out a couple of turns already, and need to do it some more tomorrow.  Probably with those metal chunks stuck in it, the pressure regulator had to be turned way in in order to hold any pressure at all.  Just sloppy work, really.
   Anyway, no leaks, pump primes, problem solved, except for getting the adjustment tweaked.  Final note:  customer support from Performance Engines is pretty pathetic.  I left 4 messages for Ron Monson late last week (he never answers his phone, far as I can tell), and he only got around to returning my call late today.  Meanwhile, I solved the problem myself.

   The other joy for the day was that when it finally quit RAINING here (all summer -- what gives?), I went over to do a test flight, and found the nose strut flat.  Filled it up, but who knows what I'll find in the morning.  If I have to send this one in to get re-built, it will make 3 out of 4 on the Lancairs I've built.  Anyone out there know, is this something I could do myself, given the right materials and some instructions?  I'm a pretty fair machinist and mechanic, but I wonder if special tools are required?

Jim Cameron
Legacy N132X
Boerne Stage Airfield (5C1)