Bill Boyd
Well Known Member
Yesterday I flew for the first time in several weeks. After start up, I noticed that the oil pressure was fairly high at idle, and would reach 99 psi at about 1400 RPM. This was at a starting oil temperature of 90F.
As the engine warmed up, the RPM required to peg the digital OP meter at 99 psi slowly increased. At an oil temperature of 120, with oil pressure reaching 99 psi at about 1900 RPM, I decided to attempt a cautious local flight. That might not have been the best call to make, since that oil pump can generate tremendous pressure, placing the filter in jeopardy if not the hoses.
When the oil temperature reached 165, the pressure began rapidly decreasing from 99 psi indicated to about 68 (uh-oh... is this a leak, or a pressure regulator becoming unstuck, or an electrical fault in the EIS-2000 going away? Good thing I'm orbiting the field) and then leveled off. Oil pressure variations with RPM from that point onward were exactly what I am accustomed to seeing, and the remainder of the flight was uneventful. No leaks evident on returning to the hangar.
Wondering if this is typical of a bypass-type Lyc oil pressure regulator that had some gunk in it, possibly from infrequent operation the last few months. If the pressure is not normal at idle next time I start up, I won't fly and will pull the regulator housing for inspection. Next oil change it will certainly get a look (20 hours from now, most likely.) Last oil change, the filter element was free of any contamination.
Thoughts from the engine guys??
-Stormy
As the engine warmed up, the RPM required to peg the digital OP meter at 99 psi slowly increased. At an oil temperature of 120, with oil pressure reaching 99 psi at about 1900 RPM, I decided to attempt a cautious local flight. That might not have been the best call to make, since that oil pump can generate tremendous pressure, placing the filter in jeopardy if not the hoses.
When the oil temperature reached 165, the pressure began rapidly decreasing from 99 psi indicated to about 68 (uh-oh... is this a leak, or a pressure regulator becoming unstuck, or an electrical fault in the EIS-2000 going away? Good thing I'm orbiting the field) and then leveled off. Oil pressure variations with RPM from that point onward were exactly what I am accustomed to seeing, and the remainder of the flight was uneventful. No leaks evident on returning to the hangar.
Wondering if this is typical of a bypass-type Lyc oil pressure regulator that had some gunk in it, possibly from infrequent operation the last few months. If the pressure is not normal at idle next time I start up, I won't fly and will pull the regulator housing for inspection. Next oil change it will certainly get a look (20 hours from now, most likely.) Last oil change, the filter element was free of any contamination.
Thoughts from the engine guys??
-Stormy
Good thought, though.
