Fairchild Club Forum

'I just put an overhauled -5 on my airplane, and am having trouble
dialing in the oil pressure. On the initial post-installation flight,
the pressure was way to low, down around 25/30 lbs. We adjusted the
pressure relief valve, and now, although on start up the oil pressure
is too high, around 100 lbs, operationally during flight it stays at 40
lbs. I am looking for a way to lower the pressure on start up, and
increase the operational pressure during flight. Any thoughts?'

'I have a 1938 short-nosed F-24 with a 175 hp Ranger engine. The oil pressure reads 100psi at startup. After flying for 10 minutes the oil temperature is 195 degrees and the oil pressure is 40 psi. The oil pressure, at idle, is 18 or 19 psi. I have been told, by my AP, that minimum oil pressure, in flight, is 50 psi and is 15 at idle. Max oil temp is 200.

I need some expert advice. Can this be helped by screwing in the oil pressure relief valve? Is this the sign of bad bearing clearances? I am using 60 weight mineral aircraft oil with some STP added.

Can new bearings be installed without removing the engine?

Thanks, in advance. Norbert Mc Luckie, near Kankakee, Illinois
815 472 2523 cell 305 942 7066

Lucky

[Non-text portions of this message have been removed]'

'Lucky,

Here are the numbers right out of the Ranger Book.

Oil pressure Min Idle 15lbs
Oil pressure Max 70lbs at cruise
Oil pressure Min at cruise 50lbs
Oil pressure desired at cruise 60lbs

Max oil temp 200f
Min oil temp 100f
Desired temp 140 - 170f.

Now, rule of thumb, add 100 degrees F over outside air and your good to go.

If your oil pressure is still good, above 15lbs that bearings are not to far worn.

Sounds like your oil pump is not too worn, if it puts out 100lbs.

I would drain oil if not already. Use the 60wt. I would clean the oil pressure relief. Inspect for trash and pitting. The spring is most likely a little week. Adjust oil presure one turn at a time. Then go fly. Compare results.

Will require engine removed for major overhaul. Chances are you will need other work also.

Feel free to call me.


Jamie



Jamie S. Treat
Aircraft Restoration & Repair, LLC
IAC 5, Chapter President
http://iac5.org
Kelly Airpark (CO15) http://www.kellyairpark.com
24201 David C. Johnson Loop
Elbert, CO 80106

New Email: JamieTreat@q.com
Hm/Hgr 303-648-0130
Cell 303-304-7937

Quote of the Month: When asked by someone how much money flying takes: Why, all of it! - Gordon Baxter

----- Original Message -----
From: Norbert J. Mc Luckie
To: fairchildclub@yahoogroups.com
Sent: Thursday, June 18, 2009 8:02 AM
Subject: [fairchildclub] Ranger oil pressure





I have a 1938 short-nosed F-24 with a 175 hp Ranger engine. The oil pressure reads 100psi at startup. After flying for 10 minutes the oil temperature is 195 degrees and the oil pressure is 40 psi. The oil pressure, at idle, is 18 or 19 psi. I have been told, by my AP, that minimum oil pressure, in flight, is 50 psi and is 15 at idle. Max oil temp is 200.

I need some expert advice. Can this be helped by screwing in the oil pressure relief valve? Is this the sign of bad bearing clearances? I am using 60 weight mineral aircraft oil with some STP added.

Can new bearings be installed without removing the engine?

Thanks, in advance. Norbert Mc Luckie, near Kankakee, Illinois
815 472 2523 cell 305 942 7066

Lucky

[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]

'

'Lucky,

I would worry with 40#. I have the 200hp and cruise at nearly 65#. Even cold, mine won't go over 70#. Because I have the huge oil cooler hanging out under my chin, I never see oil temp over 150.

I agree with Jamie that you should open the pressure relief valve and look for carbon or varnish. I would also tighten it one turn and then try it.

Your 100# on startup might be from clogged oil lines. This, in addition to the high oil temps, might lead me to remove the oil cooler and 'clean it out'. We know a farmer with a PT that fills his cooler with solvent and straps it to his plow, and after eight hours of plowing, all of the crud has been shaken loose and he only has to rinse it out.

Good luck, and let us know what you come up with.

Bob Waldron
1939 Fairchild 24K
Webster, MN

--- In fairchildclub@yahoogroups.com, "Norbert J. Mc Luckie" wrote:
>
> I have a 1938 short-nosed F-24 with a 175 hp Ranger engine. The oil pressure reads 100psi at startup. After flying for 10 minutes the oil temperature is 195 degrees and the oil pressure is 40 psi. The oil pressure, at idle, is 18 or 19 psi. I have been told, by my AP, that minimum oil pressure, in flight, is 50 psi and is 15 at idle. Max oil temp is 200.
>
> I need some expert advice. Can this be helped by screwing in the oil pressure relief valve? Is this the sign of bad bearing clearances? I am using 60 weight mineral aircraft oil with some STP added.
>
> Can new bearings be installed without removing the engine?
>
> Thanks, in advance. Norbert Mc Luckie, near Kankakee, Illinois
> 815 472 2523 cell 305 942 7066
>
> Lucky
>
> [Non-text portions of this message have been removed]
>

'