What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Oil pressure

A

alcladrv

Well Known Member
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
 
oil pressure

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.
 
Whats' normal?

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


Allen Barrett said:
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.
Click to expand...
 
85 lbs. is a little high for my taste.

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.
 
Dennis Madden said:
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
Click to expand...

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).
 
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
 
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
 
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?
 
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
 
Larry, do you have anything on the vacuum pad? If not.. is the gear installed? If not.. try putting it in.. I've seen that make difference in oil pressure reading.. actually, very, very similar to what you describe..
 
Radomir said:
Larry, do you have anything on the vacuum pad? If not.. is the gear installed? If not.. try putting it in.. I've seen that make difference in oil pressure reading.. actually, very, very similar to what you describe..
Click to expand...

Good idea! I'll check it next time I have the cowel off.
 
OIL PRESSURE/OIL LEAK

I ALSO BUILT AN ECI 0360 ENGINE. AFTER THE ENGINE WAS BUILT I RECEIVED A CALL FROM ECI REGARDING THE FRONT THROUGH BOLT. THERE WAS A PROBLEM IN THE MILLING OF SOME OF THESE ENGINES. I HAD TO PULL THE THROUGH BOLT AND CHECK TO SEE IF MINE HAD BEEN MISS DRILLED. I WAS TOLD THAT IT WOULD NOT BE A PROBLEM IN THE OPERATION BUT I WOULD PROBABLY HAVE A LEAK AT THAT BOLT. YOU MIGHT WANT TO CALL THE BUILDER AND OR ECI.
 
Oil pressure anomoly

I just had a strange thing happen on my return flight from Montana. Cruising at 11500' and my normal cruise oil pressure of 80psi and when i reduced power about a 100 rpm to descend, I noticed my oil pressure went out of limits upward. My RMI pegged out at 99, so it may have been even higher. New one on me. If I added power it came back down. What gives? First time that has happened on my O-320-D1A. It stayed high all the way down to landing at 1575' elev. On the next leg home, same thing happened only this time I was at 5500' and started a descent into STL and the oil pressure went up again, although not over 96 that time. Very strange. What could that be? Oil temp was running at the normal of 185 in cruise and only dropped to 169 on both descents.
 
If the temperature remained constant I would guess your oil pressure sending unit was headed for the re-cycle bin.

What is an RMI reading?
 
Last edited:
49clipper

The RMI is my Rocky Mountain Instrument engine monitor. I can't see how its the instrument when it works fine in all conditions except descent on a power reduction.
 
49clipper said:
The RMI is my Rocky Mountain Instrument engine monitor. I can't see how its the instrument when it works fine in all conditions except descent on a power reduction.
Click to expand...

I agree, but you gotta look somewhere. I suspect the oil pressure sending unit. It's a cheap place to start! :D
 
In response to "49 Clipper"'s post regarding his oil pressure going up, when the engine RPM goes down, his problem may not be the oil pressure gauge/sender system. I had a similar problem. With a recently extensively overhauled Lyc. 0-360 B2A (ECI cyl. etc.) I installed washers under the non-adjustable cap on the oil relief valve, to increase the oil pressure. It did - but - after the oil warmed up the oil pressure went down (normal). When I reduced RPM (fixed prop), the oil pressure went UP! (NOT NORMAL) I changed the non-adjustable oil relief valve cap to an adjustable cap, and the oil pressure has been good and the pressure goes down when the RPM is reduced. I know, I know - that should not have fixed it. All either cap does is hold the spring. So - if anyone has an explanation, I would like to know.
Burton Cooper
Recently completed, flying RV6
 
You must log in or register to reply here.
Back
Top