Oil pressure question

[MooneyBob]

I just got new CGR30P engine monitor installed ( together with other gadgets in the panel ) and I will have some questions. Here is the first one:

With the old oil pressure gauge I would say the oil pressure was always in the green in the upper half of the green range. Even when idle. I think it was the case. Not 100% sure. I have IO360 A3B6 engine.

Now with the CGR my oil pressure indication is in yellow ( together with the yellow warning light) up to around 1200 RPM. I don't believe my oil pressure changed. I am just curious what it the normal number value of the oil pressure in range of 900-1200 RPM and then 2500 RPM for example.

Now the digital RPM display reads 2670 RMP full power on take off. Should it be 2700 even ? Should I check the RPM with the " RPM meter" or whatever you call it if it matches to the display?

What is good CHT value / range in cruise?

Thanks.

[Ragsf15e]

Bob -

 

I've got a JPI930 so most of the same data you're talking about.  I think sometimes we have "TMI" (too much info!).  Here are my responses to your points though and what I see on my A1A engine in the M20F...

 

Oil pressure will go into the upper end of the yellow (I think that's below 60psi) in idle after flight (when the oil is warm and thin).  Generally it'll be in the green at idle when it's colder.  This is consistent with the manual that gives a different pressure requirement at idle (thus the yellow range).  My oil pressure is always solidly in the green at normal flight settings with oil around 180-195 degrees F though.

 

My RPM usually shows 2710 or 2720 on takeoff so it goes red... am I overspeeding the engine every time I takeoff?  I think not.  If I had a normal analog gauge the needle is probably 50 RPM fat anyway.  You can certainly test the RPM, but I suspect it's well withing tolerances and the gauge is just giving us more info than we need.

 

Finally, good question on the CHTs... lots of techniques on these.  Most people say to keep them below 380 in cruise / 400 or less in climb or something like that.  It will depend on how you lean - i usually cruise around 6 to 10,000 and lean to peak or slightly lean of peak.  This winter I've been showing about 1-290, 2-330, 3-330, 4-310.  I show more like 380 on #2/#3 in the climb.  In the summer I keep them around 380 to 400 in climb and around 350 in cruise.

 

I'd like to know how stable your fuel pressure is during climb immediately after you turn off the electric pump... mine is all over the place.  Scared me a few times, but stays in the green although goes right to the bottom of it sometimes.  No change in flow and the engine runs perfectly.

 

Rags

[MooneyBob]

Bob -

 

I've got a JPI930 so most of the same data you're talking about.  I think sometimes we have "TMI" (too much info!).  Here are my responses to your points though and what I see on my A1A engine in the M20F...

 

Oil pressure will go into the upper end of the yellow (I think that's below 60psi) in idle after flight (when the oil is warm and thin).  Generally it'll be in the green at idle when it's colder.  This is consistent with the manual that gives a different pressure requirement at idle (thus the yellow range).  My oil pressure is always solidly in the green at normal flight settings with oil around 180-195 degrees F though.

 

My RPM usually shows 2710 or 2720 on takeoff so it goes red... am I overspeeding the engine every time I takeoff?  I think not.  If I had a normal analog gauge the needle is probably 50 RPM fat anyway.  You can certainly test the RPM, but I suspect it's well withing tolerances and the gauge is just giving us more info than we need.

 

Finally, good question on the CHTs... lots of techniques on these.  Most people say to keep them below 380 in cruise / 400 or less in climb or something like that.  It will depend on how you lean - i usually cruise around 6 to 10,000 and lean to peak or slightly lean of peak.  This winter I've been showing about 1-290, 2-330, 3-330, 4-310.  I show more like 380 on #2/#3 in the climb.  In the summer I keep them around 380 to 400 in climb and around 350 in cruise.

 

I'd like to know how stable your fuel pressure is during climb immediately after you turn off the electric pump... mine is all over the place.  Scared me a few times, but stays in the green although goes right to the bottom of it sometimes.  No change in flow and the engine runs perfectly.

 

Rags

Excellent. Thanks. And you are right about too much and too precise information. Nice wide green field on the gauge gives you peace of mind. Digital numbers freaks you out.

[slowflyin]

Mine does the same.   Yellow at idle and RPM goes to 2730 on first flight of the day but then usually normal after that.

[RobertGary1]

Same here. I called Lycoming about it once. They said that on the ground in the yellow is perfectly fine. Even on final at idle its ok.

 

BTW: The oil temp indication on my EDM changed my life. I got a warning of rising oil temps a couple years ago before cylinders started going off line. So its paid for itself 1000 times over in early warning.

 

-Robert

[Marauder]

Bob -

 

I've got a JPI930 so most of the same data you're talking about.  I think sometimes we have "TMI" (too much info!).  Here are my responses to your points though and what I see on my A1A engine in the M20F...

 

Oil pressure will go into the upper end of the yellow (I think that's below 60psi) in idle after flight (when the oil is warm and thin).  Generally it'll be in the green at idle when it's colder.  This is consistent with the manual that gives a different pressure requirement at idle (thus the yellow range).  My oil pressure is always solidly in the green at normal flight settings with oil around 180-195 degrees F though.

 

My RPM usually shows 2710 or 2720 on takeoff so it goes red... am I overspeeding the engine every time I takeoff?  I think not.  If I had a normal analog gauge the needle is probably 50 RPM fat anyway.  You can certainly test the RPM, but I suspect it's well withing tolerances and the gauge is just giving us more info than we need.

 

Finally, good question on the CHTs... lots of techniques on these.  Most people say to keep them below 380 in cruise / 400 or less in climb or something like that.  It will depend on how you lean - i usually cruise around 6 to 10,000 and lean to peak or slightly lean of peak.  This winter I've been showing about 1-290, 2-330, 3-330, 4-310.  I show more like 380 on #2/#3 in the climb.  In the summer I keep them around 380 to 400 in climb and around 350 in cruise.

 

I'd like to know how stable your fuel pressure is during climb immediately after you turn off the electric pump... mine is all over the place.  Scared me a few times, but stays in the green although goes right to the bottom of it sometimes.  No change in flow and the engine runs perfectly.

 

Rags

 

 

Excellent. Thanks. And you are right about too much and too precise information. Nice wide green field on the gauge gives you peace of mind. Digital numbers freaks you out.

 

My RPM reds lower than the old mechanical tach as well and considering the error in the instrument itself, I am fine with it. That said, the tachometer on these electronic monitors are not taken from the cable to the monitor, but rather, from a pickup on the mags. I wonder if this makes the readout more accurate?