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Proper oil psi mid-time IO-360

jdeas

Well Known Member
First the good, I have a mid-time IO-360 with 150hrs since overhaul. This engine had the cam/lifters reground and was pickled for over 12 years in a dry environment. Pulling a jug showed no internal corrosion.
I now have 8 hrs of phase one flight and oil pressure (15w-50) around idle speed is ~35-40psi. At 2700rpm the system is up to 70psi and at 2300rpm around 55-60.
I was expecting more around 75-85psi at 2300 given only 150hrs.

Waiting for 10hrs to do oil analysis but cutting a filter at 1hr (little metal) and 5 hrs (one flake non-magnetic) appears to be good. What is the chance that this is simply the oil relief valve and I just need to add a few washers? Or better yet, is this within expected limits at 150hrs?
 
Fixed regulator

Unless I am missing something, the oil relief valve is the regulator and this one is fixed (uses washers to change values)
 
Unless I am missing something, the oil relief valve is the regulator and this one is fixed (uses washers to change values)

The IO360s I am familiar with have an adjustable regulator on the right side case half, top side, just forward of the plane of the motor mount. But it could be that that feature is version-specific.

Thanks, Bob K.
 
well.. put more washers ;) it is adjustable.. just not as easy as the real adjustable one...
 
Diff name for same device.

The IO360s I am familiar with have an adjustable regulator on the right side case half, top side, just forward of the plane of the motor mount. But it could be that that feature is version-specific.

Thanks, Bob K.

Yes, I have seen versions that are screw adjustable. This one is adjusted using washers.
 
well.. put more washers ;) it is adjustable.. just not as easy as the real adjustable one...

I understand that, but with the idle pressure above norms and cruise speeds below, I wanted an opinion from someone who has done this type of work to chime in on the reason. I.E. low flow, leaking bypass valve or normal but out of adjustment.
 
First the good, I have a mid-time IO-360 with 150hrs since overhaul. This engine had the cam/lifters reground and was pickled for over 12 years in a dry environment. Pulling a jug showed no internal corrosion.
I now have 8 hrs of phase one flight and oil pressure (15w-50) around idle speed is ~35-40psi. At 2700rpm the system is up to 70psi and at 2300rpm around 55-60.
I was expecting more around 75-85psi at 2300 given only 150hrs.

I looked at my Phase 1 data on a than new IO-360M1B. I didn't note idle oil pressure, other than it was above 25 psi. At cruise powers the oil pressure varied between 70 and 74 psi with Phillips 66 20W-50.

-John
 
First the good, I have a mid-time IO-360 with 150hrs since overhaul. This engine had the cam/lifters reground and was pickled for over 12 years in a dry environment. Pulling a jug showed no internal corrosion.
I now have 8 hrs of phase one flight and oil pressure (15w-50) around idle speed is ~35-40psi. At 2700rpm the system is up to 70psi and at 2300rpm around 55-60.
I was expecting more around 75-85psi at 2300 given only 150hrs.

Waiting for 10hrs to do oil analysis but cutting a filter at 1hr (little metal) and 5 hrs (one flake non-magnetic) appears to be good. What is the chance that this is simply the oil relief valve and I just need to add a few washers? Or better yet, is this within expected limits at 150hrs?

I think your just fine, after O/H mine was 55 at cruse, we added washers to get it to 70 in cruse, and it?s been steady now for 1250 hours. Time for you to get to adding some washers, I don?t remember the value of PSI per washer but I think I added 5 or 6, maybe start with 4 and see how it goes.
 
It just looks like you need to adjust up as others have suggested. Lycoming used three types of relief valve caps. one known as the short tower that looks like a derby hat. this takes max 4 washers and another known as the tall tower that looks like a stove pipe hat and that can take up to 9 washers. and the adjustable one that has a screw adjustment sticking out of it.
You normally get 3-5 psi increase per washer or full turn on an adjustable one.
Add washers to get 60 psi at 1400 RPM with warm (100* plus) oil and it will be at 75 psi inflight during cruise.
If you can't get the correct psi after getting to the max adjustment the are several different springs to substitute to get you to the correct limits.
Good Luck and happy New Year,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
It just looks like you need to adjust up as others have suggested. Lycoming used three types of relief valve caps. one known as the short tower that looks like a derby hat. this takes max 4 washers and another known as the tall tower that looks like a stove pipe hat and that can take up to 9 washers. and the adjustable one that has a screw adjustment sticking out of it.
You normally get 3-5 psi increase per washer or full turn on an adjustable one.
Add washers to get 60 psi at 1400 RPM with warm (100* plus) oil and it will be at 75 psi inflight during cruise.
If you can't get the correct psi after getting to the max adjustment the are several different springs to substitute to get you to the correct limits.
Good Luck and happy New Year,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

Thanks! Question answered and a practical workflow to get there!
 
good job Mahlon

Mahlon is dead on with this one. My only comment is that your readings "now" are some that I would go with all day long and have no squocks with. From the new valve pressure set-up values it is expected that the springs will get older as time go's on. There will be wear in the engine and the set-up pressure will go down over time. The levels you are quoting are one's we see in the field with no problems to speak of. If you are not getting any metal in a filter or screen after 20-40 hours "and you will get some from beak-in" then you may wish to have some fun with your new toy for a while. 2014 what a cool time to fly. Hope this helps.
Yours as always R.E.A. III # 80888
 
I tried the white spring

And it resulted in way too high oil pressure. So I added 4 washers for a total of 7 in my prv. And just finished a 15 hr round trip from the Chicago area to McAllen Tx in the Rio Grande Valley and the oil pressure was rock steady at 82 psi when it used to be only 60psi or so. My 140hr. 0-320 used about 1qt on the trip and as soon as the weather gets above 0F I will go out and try to determine if the increased pressure caused any leakage.
 
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