gsxrpilot Posted March 26, 2014 Report Posted March 26, 2014 As a newbie Mooney owner, I'm a bit anxious about all kinds of things. And at the risk of being told to go study the POH, I'm gonna ask the question anyway. My oil pressure gauge indicates in the yellow/high yellow on take off. As soon as I dial the power back to 25/25 it settles back into the green. I'm showing 6 qt's on the stick and it's nice and clean. The engine runs really smooth and seems to make plenty of power. I'm in Texas and so the temps are pretty mild. Should I be concerned? Or is this normal for an O360? Thanks, Paul Quote
1964-M20E Posted March 26, 2014 Report Posted March 26, 2014 What's the oil temp? What pressure is the yellow zone on your aircraft? I this normal to be in the yellow I'm not sure but an engine will produce more oil pressure at higher RPMs and colder oil temps. Conversely lower RPMs and higher oil temperatures will produce lower oil pressure. Quote
Marauder Posted March 26, 2014 Report Posted March 26, 2014 Oil temp does play a role in what the oil pressure will be. I also think the actual measurement can be off. If you look at the attached photo, my oil pressure reading on the JPI 830 shows 73 psi. The factory gauge looks to be over 80. Sent using Tapatalk Quote
Andy95W Posted March 26, 2014 Report Posted March 26, 2014 I completely agree with Marauder. First flight of the day oil pressures are usually higher than later ones, since oil at 180 deg. Is much less viscous than at 120. And the old gauges are horribly inaccurate. My engine was overhauled by a very reputable shop that dyno- tested everything and set the oil pressure based on calibrated test equipment. In the airplane, oil pressure is in the yellow on takeoff and high-green arc in cruise, although it does drop some as oil temperature rises. Makes you wish you had Marauder's engine monitor, doesn't it? I sure do... 1 Quote
jrwilson Posted March 26, 2014 Report Posted March 26, 2014 Yep, normal. High power + low temps = higher oil pressure. Quote
bonal Posted March 26, 2014 Report Posted March 26, 2014 Marauder you just wanted to let everyone see your very cool panel. pressure on my envy meter went way up. 1 Quote
Marauder Posted March 26, 2014 Report Posted March 26, 2014 Marauder you just wanted to let everyone see your very cool panel. pressure on my envy meter went way up. Too funny! There are a few of us here who could help spend your money and help alleviate the envy meter. Quote
N201MKTurbo Posted March 26, 2014 Report Posted March 26, 2014 I set my oil pressure so it is at the bottom of the green arc after the oil is warm. I have found if you set it any higher you just increase the leak rate. Quote
PLN_FXR Posted March 27, 2014 Report Posted March 27, 2014 Pretty normal, Paul ... #8 above is good advice, too. There are ways to mitigate the reading being quite so high on start, but it isn't an issue as long as you're reading proper pressure at cruise and above the lower redline while idling warm. Enjoy your bird! Quote
bonal Posted March 27, 2014 Report Posted March 27, 2014 I think the most important thing is to set base line indications for your aircraft. Pressure typically rises with load and rpm and it takes a bit of time for the temps to get fully warmed up internal parts expand at different rates. What is normal for your engine Quote
jetdriven Posted March 27, 2014 Report Posted March 27, 2014 I set my oil pressure so it is at the bottom of the green arc after the oil is warm. I have found if you set it any higher you just increase the leak rate. How does it leak more with higher oil pressure? Quote
N201MKTurbo Posted March 27, 2014 Report Posted March 27, 2014 Well, I don't know for sure, but we all know that if you fill the lycoming to 8 quarts it will blow one out pretty quickly. With the oil pressure cranked way up this happens a bit faster. Quote
jetdriven Posted March 27, 2014 Report Posted March 27, 2014 Ours has about 90-95 PSI on the stock gauge but the dyno sheet from Lycoming shows 83 PSI. It does have a lot of oil on the belly but that's not a leak per se. So I'd buy that it may push some extra oil out the breather but that offset by increased oil flow to the valves. Oil that migrates past the lifters in the bore runs down the pushrod tubes to the valves. Higher oil pressure is more oil past the lifter. Quote
aaronk25 Posted April 5, 2014 Report Posted April 5, 2014 I set my oil pressure so it is at the bottom of the green arc after the oil is warm. I have found if you set it any higher you just increase the leak rate. You mean you burn more oil because the higher pressure pushes it past valve guides ect?? Quote
SkyPilot Posted April 11, 2014 Report Posted April 11, 2014 My oil pressure was doing the same thing. Not initially but about a year after I bought the airplane. It would redline on the high side on takeoff. Even in warmer temps nearing zero And this was after the oil was at normal temp. My mechanic suggested changing the pressure relief valve to a newer adjustable style and the problem was solved. We tweaked it after a few flights to get it running in the mid greens during cruise at 75%. PK Quote
FloridaMan Posted April 14, 2014 Report Posted April 14, 2014 If I recall, there is no upward oil pressure limit on takeoff for lycomings. Sent from my iPhone using Tapatalk Quote
cujet Posted April 14, 2014 Report Posted April 14, 2014 Also, be aware that it's common practice for maintenance/overhaul shops to set older Lycoming engines oil pressure to "new production" specs, which are significantly higher. Lycomings have traditionally had issues with sticking valves. One way the factory chose to reduce this issue is with the higher oil flow to the rockers/valves, via higher oil pressure. Quote
Oscar Avalle Posted April 20, 2014 Report Posted April 20, 2014 Oil temp does play a role in what the oil pressure will be. I also think the actual measurement can be off. If you look at the attached photo, my oil pressure reading on the JPI 830 shows 73 psi. The factory gauge looks to be over 80. Sent using Tapatalk Really cool panel! 1 Quote
MB65E Posted April 20, 2014 Report Posted April 20, 2014 If I recall, there is no upward oil pressure limit on takeoff for lycomings. 115psi on TO on most of the later Lycomings! Older ones were lower... -Matt Sent from my iPhone using Tapatalk Quote
Marauder Posted April 20, 2014 Report Posted April 20, 2014 Really cool panel! Thank you Oscar -- you got a nice one as well! Quote
Oscar Avalle Posted April 20, 2014 Report Posted April 20, 2014 I really would like to get the second aspen. But I am concerned about the lack of comparability between ASPEN and Garmin. I am now playing with the idea to replace the 430 with a 650 to complement the 750 Any ideas? Quote
mike_elliott Posted April 20, 2014 Report Posted April 20, 2014 I set my oil pressure so it is at the bottom of the green arc after the oil is warm. I have found if you set it any higher you just increase the leak rate. Im missing something here, where would it be leaking under pressure? Quote
N201MKTurbo Posted April 20, 2014 Report Posted April 20, 2014 I misspoke, it doesn't leak more, it consumes more. I don't know why. I could guess, but that is all it would be. I don't have any data, but I have jacked around with oil pressure a few times and every time the consumption was better at lower oil pressure. Quote
Wakeup Posted May 9, 2014 Report Posted May 9, 2014 What are the reasons for high oil pressure all the time ? Seems to me like a good thing to have VS low oil pressure. Thanks. Troy Quote
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