Todd Cullen Posted March 27, 2018 Report Share Posted March 27, 2018 Where does your oil pressure normally read? Mine has been sitting at the bottom of the green at cruise...seems a little low...compressions we’re good 30-40 hours ago but seems like they would read higher... Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted March 27, 2018 Report Share Posted March 27, 2018 Could be the gauge. Quote Link to comment Share on other sites More sharing options...
Guest Posted March 27, 2018 Report Share Posted March 27, 2018 75-80 PSI at normal cruise power and temperature. Oil type and time in service have a small effect on the reading. I would verify the reading with a test gauge before doing any adjustments to the relief valve. Clarence Quote Link to comment Share on other sites More sharing options...
Oscar Avalle Posted March 27, 2018 Report Share Posted March 27, 2018 70 to 72 in cruise. Quote Link to comment Share on other sites More sharing options...
PTK Posted March 27, 2018 Report Share Posted March 27, 2018 8 hours ago, Todd Cullen said: Where does your oil pressure normally read? Mine has been sitting at the bottom of the green at cruise...seems a little low...compressions we’re good 30-40 hours ago but seems like they would read higher... How much oil in the engine? Mine reads 7 qts on the stick and pressure is solid 80 psi on the JPI and middle of green arc. I notice as the volume drops closer to 6 qts after 10 hours or so the pressure will also drop closer to 77 and closer to bottom edge of green arc. I replenish oil back up to 7 qts and pressure recovers as well. I keep detailed records on this and measure oil always on cold engine for accuracy. Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted March 27, 2018 Report Share Posted March 27, 2018 6 hours ago, Todd Cullen said: Where does your oil pressure normally read? Mine has been sitting at the bottom of the green at cruise...seems a little low...compressions we’re good 30-40 hours ago but seems like they would read higher... The oil pressure is not a function of engine condition, it is just how the pressure regulator is adjusted. The viscosity of the oil has an effect on how the regulator works, so there is some change with oil temperature and the type of oil you run. I have always run my oil pressure at the bottom of the green with hot oil. I find the consumption is lower. Plus it is easier to tell if it changes because the edge of he needle sits right on the edge of the green. The trouble with the digital gauges is you start fussing about one PSI here and there. In every case I've seen when there is an oil pressure problem the pressure starts making wild swings from sucking air into the oil pickup, or the pressure will drop a significant amount because something came apart in your engine and is dumping oil into the sump. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted March 27, 2018 Report Share Posted March 27, 2018 (edited) Oil pressure at the bottom of the green means less oil on the valve guides and less margin for low oil volume or high oil temp, which will lead to lower oil pressure. iirc if the oil pressure drops below 60 PSI in cruise you have to take the engine apart. Mine is set up to run 90 in cruise. It left the factory that way. Edited March 27, 2018 by jetdriven Quote Link to comment Share on other sites More sharing options...
Guest Posted March 27, 2018 Report Share Posted March 27, 2018 Isn’t pump displacement in a gear pump based on pump RPM? Clarence Quote Link to comment Share on other sites More sharing options...
jetdriven Posted March 28, 2018 Report Share Posted March 28, 2018 Sure. And the oil pressure regulator has a spring and dumps the extra oil to regulate the pressure. Adding washers, a stiffer spring, or tightening down the adjustable oil pressure regulator raises oil pressure and forces more oil through the galleries, the bearings, the pushrods to the heads. I can’t see how more oil is bad here. Quote Link to comment Share on other sites More sharing options...
Piloto Posted March 29, 2018 Report Share Posted March 29, 2018 Oil pressure at idle is very much related to bearings condition. As the engine RPM is increased the oil pressure increases to the point were the relief valve is set. José Quote Link to comment Share on other sites More sharing options...
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