Oil pressure

alcladrv · #1 05-08-2008, 08:25 PM

I've seen the oil pressure range that Lycoming publishes. I've have an O-360 ECI Titan engine that came from the builder set for the low 70s. It generally settles in at 73 psi. What thoughts do others have on a good operating oil pressure?

I've got the upper through bolt just forward of #1 cylinder that seems to be leaking, starting about 20 hours ago. I just wondered if 73 psi was higher than typical and might be a cause of the leak.

Thanks, Mike

Allen Barrett · #2 05-09-2008, 08:08 AM

IMO is ideal AS LONG AS it doesn't go over 100 psi at cold start up. We set our engines up to operate at 73-76 psi when testing on our dyno.

Where are you reading your oil pressure? There is about a 10 pound difference in pressure from front to rear of engine, so if your reading the pressure from the front of the engine then you actually will be around 83 at the pump.

FYI,

Allen B.
BPE, Inc.

Dennis Madden · #3 06-03-2008, 09:35 AM

I'm wondering what could be considered "normal". I just did the oil pump gears on my 0-320, and it idles about 60psi and flys about 85 psi. I don't remember it being that high before, but is it a bad thing? I removed the inverted oil system and added an oil filter, so there is less tubing now. Maybe thats causing it?
While I'm at it, is 195 a decent oil temp to operate at? (on a 90 degree day)
Just test flew it for the first time in four months. (did LOTS of work on this plane)
Talk to me goose...
DM

Quote:

Originally Posted by Allen Barrett

IMO is ideal AS LONG AS it doesn't go over 100 psi at cold start up. We set our engines up to operate at 73-76 psi when testing on our dyno.

Where are you reading your oil pressure? There is about a 10 pound difference in pressure from front to rear of engine, so if your reading the pressure from the front of the engine then you actually will be around 83 at the pump.

FYI,

Allen B.
BPE, Inc.

Mel · #4 06-03-2008, 10:24 AM

I like to see oil pressure around 75 at cruise. 195F is a good oil temp. My personal minimum is 180F. I normally see around 190-210F.

asav8tor · #5 06-03-2008, 06:52 PM

Quote:

Originally Posted by Dennis Madden

I'm wondering what could be considered "normal". I just did the oil pump gears on my 0-320, and it idles about 60psi and flys about 85 psi. I don't remember it being that high before, but is it a bad thing? I removed the inverted oil system and added an oil filter, so there is less tubing now. Maybe thats causing it?
While I'm at it, is 195 a decent oil temp to operate at? (on a 90 degree day)
Just test flew it for the first time in four months. (did LOTS of work on this plane)
Talk to me goose...
DM

All of those numbers are excellent. And yup, removing the inverted oil system will increase the pressure reading. I would leave it there (60-85) unless you are seeing over 100 on start (perhaps more of a problem with straight wt oil).

Allen Barrett · #6 06-04-2008, 06:56 AM

I'm with Mel on this one. 85 psi is a tad high IMO. If you have an adjustable pressure relief valve you can lower the pressure a little by turning the adjustment screw counterclockwise. Each full turn of the screw will drop the pressure by about 3 lbs. If the valve is no adjustable, there may be some washers under the spring that you can remove (1 at a time) to get the pressure down.

Normal IMO is 70-76 in cruise, low 60's at hot idle.

Allen

Dennis Madden · #7 06-12-2008, 04:46 PM

Thanks fellas.
I found an old 0-320 overhaul manual in the hangar and it gave an acceptable range of (from memory here, not exact but close) 35 psi for a low, and the high was 85 psi. I have 60 psi cold at idle. The 85 warm at cruise is "technically" OK, but I think I will go ahead and lower it a bit just in case. Probably ought to check the pressure remotely from another source just to back up my gage huh? Don't want to chase any more shadows here. I'm a bit conservative, and don't like readings on either "end" of the envelope. I want it all right fat in the middle. ;-)
Thanks again,
DM

Geico266 · #8 08-13-2008, 04:21 PM

I have an IO-540 giving me a tad bit of concern so I thought I would tag a post onto this thread.

I warm the oil up on idle to 100F (60 PSI) before take off, and I can still hit 102 PSI on climb out until the oil gets warmer. Question is at cruise oil temps 185F my oil pressure is 63 PSI. That sounds a tad low by reading this thread. If I adjust the pressure relief value to get a higher cruise oil pressure won't that really be pushing the OP on take off?

Any thoughts?

hgerhardt · #9 08-13-2008, 08:30 PM

Aren't new Cessna and Robinson helicopter O-360's redlined at 125 psi or so? With the identical oil pump and most other parts as we run in our RV's? So what's the problem with higher pressure? Obviously, the higher pressure won't hurt a thing and you'll get more oil to the exhaust guides (a good thing), which I suspect is why Lycoming increased the pressure.

In fact, those of you who've bought factory new Lycomings from Van's recently, what pressure was/is your engine set to?

Heinrich Gerhardt

Geico266 · #10 08-13-2008, 08:44 PM

I've been told (could be old pilot's tale) OP over 100PSI can "swell" the oil cooler.