REFLECTOR:Lycoming IO-540 - very low oil pressure after flight.

John Cervini reflector@tvbf.org
Fri, 20 Feb 2004 00:07:36 -0500


I have a 1000 hr TT IO-540, the top end has been rebuilt to 0 hrs by a
reputable company in Florida (my location).
I have about 18 running hrs on it so far.

It starts fine and really gets my XL-RG off the ground nicely - plenty of
power.  I registered the aircraft in November and I have had 8 flights in
phase 1.
CHT max is around 365 on climb to a few thousand feet.  Upon startup the oil
pressure is around 95 psi then quicky starts to drop to normal range when
the engine gets to operating temp.  It's around 50-60 psi by the time I am
taxiing.  However, when I land, with the throttle at minimum position, the
oil pressure drops to a low value, so low that the Micro Vision indicator
goes into alarm (below 18-20 psi).  By design the oil pressure display goes
blank to indicate a low pressure warning - which is not a nice thing to see.

I imagine the engine as being a metal balloon filled with pressurized oil
(while running).  For the pressure to drop, basically there should be a
leak.  Since I don't see any oil squirting out of any holes in the engine I
don't know what to look at first.  (very simple analogy on my part)

Any ideas.


john cervini
N444GX