Continued Oil Pressure Problems and Muffler Shroud

This morning I went to 3D Sheet Metal and had my good friend Sterling Smith (CEO) roll a shroud (shield) for the front of the muffler.  I had Sterling roll a 14” long half-pipe (6” diameter) to be installed on the front of the muffler between the muffler and the oil cooler.  I cut out the top 2-corners and drilled a series of holes in 2-rows.  The holes are to allow some air to flow through the shield and provide cooling for the muffler.

I then installed 2-pipe clamps with 3-3/8” machine screws to hold the shield close to ¼” off of the face of the muffler.  I put it in place and tightened the clamps.  I must admit I am pleased with the way it turned out.  I think this will be a good solution to my high oil temps on hot days.  I put the cowlings back on the nose and pulled the airplane out to fly it in the pattern.  I thought I could go up and do a few touch-and goes.  As soon as I started the engine I knew I was in trouble.  The oil pressure was all over the place.  Very unlike it was the day I moved the oil pressure sensor to the firewall.  It seemed to settle down as I let the oil temperature come up.  I taxied out to the run-up area and as soon as I advanced the throttle to 4,000 RPM all hell broke loose.  The oil pressure went from 8 psi to 65 psi and everyplace in between.  The SkyView begin annunciating an oil pressure warning each time it dropped into the red.  As I throttled back it seemed to settle down a little bit, but not much.  When I throttle up again the same thing happened. 

I decided to return to the hanger and remove the top cowling to see if there was a leak somewhere.  Upon removing the cowling I could see everything was fine.  No leaks and all connections were good.  I restarted the engine.  No change – just jumpy oil pressure readings.  I shut it down and moved the airplane back into the hangar.  I returned home and called Lockwood Aviation. I spoke to a tech named Mike. I told him I thought I have a bad oil pressure sensor.  I told him all of the problems I have had and the attempted relocation of the sensor as a solution.  He said it is very likely the oil pressure sensor has gone bad, but he told me before I purchase a new one I should install a mechanical oil pressure gauge and make sure the sensor is wrong.  I told him I would do so.  I went to O’Reily Auto Parts and purchased an oil pressure gauge.  I went to Lowe’s and purchased a tee and some fittings to install the gauge in the oil pressure line.  I put the contraption together and pulled the airplane out and started the engine.

This time there was a big red X through the oil pressure gauge on the SkyView screen.  However, the oil pressure on the mechanical gauge was rock solid at 60 psi.  I shut the engine down and checked the fittings.  All seemed to be good. I decided to re-crimp the spade connectors in the electrical system.  I re-crimped the 4-connectors, 2-on the sensor wire and 2-on the wire from the instrument area.  I restarted the engine and the same condition existed.  No oil pressure on the SkyView, but the oil pressure on the mechanical gauge continued to be rock solid.  I waited for the oil temperature to rise and then advanced the throttle to 4,000 RPMs.  The oil pressure gauge continued to hold at 60 psi.  There were small fluctuations when I would throttle back or advance the throttle but the pressure would quickly return to 60 psi and stay there.  I guess I will need a new oil pressure sensor.  I will call Lockwood in the morning and buy the Honeywell oil pressure sensor kit.  I hope this will be the solution.