IO-360 A1A Oil pressure

[FastTex]

18 minutes ago, M20F-1968 said:

So I am still trying to sort out my oil pressure issue.  The engine is an Lycoming IO-360 A1A

I started out with 60 psi in cruise, with 40 year old spring, #68668 and 4 washers = 60 psi

Added 3 washers = 61 psi

Changed to new 61084 spring, with 2 washers, ground ran with 75 psi (cold old oil)

Added two more washers with 61084 (now total 4 washers) = ground run-up to 2000 RPM = 80 psi

1 week later, flew the plane after changing oil, 60 psi upon starting and 60 - 67 (at most) in cruise (typically 62-63 psi)

I think I need to put a gauge of the engine to determine what pressure I actually have.  Perhaps put in the next heavier spring (LW-18085)

Any thoughts?  Should it matter that it is turbo normalized, therefore has more oil volume in the system?

John Breda

I have the same oil pressure you do and my mechanic is installing an adjustable regulator replacing the old spring/washer driven one. I have overhauled the whole gauge panel and I will be testing it on Friday. According to my gauge (analog between yellow and green, JPI see above) I'm kind of low. I think it should be at least @70psi in cruise. I will set the regulator to give me that pressure. I will share the results.

[Guitarmaster]

Failing oil pump, ring/cylinder issues, worn valve stem guides.
My money would be on the oil pump.

Just throwing out ideas. Your mileage may vary.

Sent from my Pixel 2 XL using Tapatalk

[FastTex]

8 hours ago, Guitarmaster said:

Failing oil pump, ring/cylinder issues, worn valve stem guides.
My money would be on the oil pump.

Just throwing out ideas. Your mileage may vary.

Sent from my Pixel 2 XL using Tapatalk
 

Any idea about the cost of an oil pump and/or cost to overhaul it?

[ArtVandelay]

Any idea about the cost of an oil pump and/or cost to overhaul it?

I think oil pumps going bad is a fairly rare occurrence, most oil pressure problems are bad sender or lack of oil or a restriction in the oil lines:
I would check the pickup screen which rarely gets serviced and oil cooler.

[Guest]

The first step should be to verify the accuracy of the oil pressure gauge with a known test gauge plumbed in parallel with the ship gauge.

Old oil pumps were a 2 piece body, newer are a 1 piece design.  The are several AD’s on pumps as well, most should be complied with long ago, but it does get missed.  Gears made of sintered metal and some with woodruff key drives and 2 piece bodies are obsolete.

Pumps generally don’t wear out unless your cam and lifters are failing and hard bits of metal are chewing the pump body as they pass through.  This and worn bearings will lower oil pressure.

Clarence

[Alyair]

As an automotive engine rebuilder.  I would suggest if you have a higher time engine, not to overlook the possibility of excessive wear of the connecting rod bearings. They take a beating on every power stroke. A few extra thousands of an inch let’s a lot oil squeeze out. The oil pump cannot overcome the extra flow and therefore will not develop the pressure. I own a M20E with a 360A1A. It has 1900 hours and my oil pressure is 50psi at hot idle and low 60s at 2600rpm. We installed an ESI MVP50. When the pressure is under 60psi the yellow warning light flashes. Annoying!  I added washers to the pressure relief valve. It didn’t make any difference.

[FastTex]

2 hours ago, Alyair said:

As an automotive engine rebuilder.  I would suggest if you have a higher time engine, not to overlook the possibility of excessive wear of the connecting rod bearings. They take a beating on every power stroke. A few extra thousands of an inch let’s a lot oil squeeze out. The oil pump cannot overcome the extra flow and therefore will not develop the pressure. I own a M20E with a 360A1A. It has 1900 hours and my oil pressure is 50psi at hot idle and low 60s at 2600rpm. We installed an ESI MVP50. When the pressure is under 60psi the yellow warning light flashes. Annoying!  I added washers to the pressure relief valve. It didn’t make any difference.

How are you planning to resolve it eventually? Oil pump overhaul?

[Alyair]

My plan is to just live with it until I replace or rebuild the engine. 50 psi is still 50psi.

we are doing oil analysis and we check the filter for metal.

[takair]

For what it’s worth, I think the trend is the most important thing to look for.  As others have said, pump condition, bearing condition, etc contribute to baseline oil pressure.  If it starts going down, something is going on.  If it is 60 or 70 for hundreds of hours you should be good.  If it starts trending down over the course of a few hours...pay attention.

[FastTex]

Here it is after installing an adjustable regulator and tuning the pressure. Everything (engine sound, oil temp, oil pressure) appears to be working better!

And yes...there is not CHT probe connected. I have a JPI830! I was also testing the fuel gauges and flying on the right tank.

 

[Guest]

1 hour ago, FastTex said:

Here it is after installing an adjustable regulator and tuning the pressure. Everything (engine sound, oil temp, oil pressure) appears to be working better!

And yes...there is not CHT probe connected. I have a JPI830! I was also testing the fuel gauges and flying on the right tank.

 

Great news on the oil pressure!

I don’t think the 830 is certified as primary, so your original CHT has to continue to work.

Clarence

[FastTex]

2 minutes ago, M20Doc said:

Great news on the oil pressure!

I don’t think the 830 is certified as primary, so your original CHT has to continue to work.

Clarence

Is the CHT required?

[Guest]

Just now, FastTex said:

Is the CHT required?

My understanding is that your airframe has cowl flaps so CHT is required.  So it must be original or a certified replacement.

Clarence

[FastTex]

Just now, M20Doc said:

My understanding is that your airframe has cowl flaps so CHT is required.  So it must be original or a certified replacement.

Clarence

Thanks! Interesting...I will need to look into it...

[N201MKTurbo]

2 hours ago, M20Doc said:

My understanding is that your airframe has cowl flaps so CHT is required.  So it must be original or a certified replacement.

Clarence

Apparently, it is not required.

https://www.law.cornell.edu/cfr/text/14/91.205

If it is listed in the type certificate then it will require an STC to change it.

[N201MKTurbo]

10 minutes ago, N201MKTurbo said:

Apparently, it is not required.

https://www.law.cornell.edu/cfr/text/14/91.205

If it is listed in the type certificate then it will require an STC to change it.

I found the cowl flap thing. It is in the CAR-3 and part 23 certification standards. So, the mooney would be required to have a CHT gauge.

[MikeOH]

Slight thread creep question:

Not sure if this has been going on since I bought my plane last year, but yesterday I was watching my oil pressure gauge for 5 to 10 seconds, rather than just a glance, and noticed it 'twitches' every few seconds, as does my Insigt G3; maybe a 3 psi change rather than a steady reading.

Normal? Anything to worry about?

Thanks!

[FloridaMan]

On 9/22/2018 at 7:13 PM, MikeOH said:

Slight thread creep question:

Not sure if this has been going on since I bought my plane last year, but yesterday I was watching my oil pressure gauge for 5 to 10 seconds, rather than just a glance, and noticed it 'twitches' every few seconds, as does my Insigt G3; maybe a 3 psi change rather than a steady reading.

Normal? Anything to worry about?

Thanks!

Is it a drop, and if so, what does it drop to? 

[Guest]

On 9/22/2018 at 7:13 PM, MikeOH said:

Slight thread creep question:

Not sure if this has been going on since I bought my plane last year, but yesterday I was watching my oil pressure gauge for 5 to 10 seconds, rather than just a glance, and noticed it 'twitches' every few seconds, as does my Insigt G3; maybe a 3 psi change rather than a steady reading.

Normal? Anything to worry about?

Thanks!

There are a few SB’s from Lycoming on the oil pressure relief valve, depending on part number and age of the engine.  Worth contacting them about.

Clarence

[N201MKTurbo]

On 9/22/2018 at 4:13 PM, MikeOH said:

Slight thread creep question:

Not sure if this has been going on since I bought my plane last year, but yesterday I was watching my oil pressure gauge for 5 to 10 seconds, rather than just a glance, and noticed it 'twitches' every few seconds, as does my Insigt G3; maybe a 3 psi change rather than a steady reading.

Normal? Anything to worry about?

Thanks!

I have found if it twitches, you are drawing air into the pickup. Whenever a bubble is sucked in it causes the twitch. Try adding more oil. If that doesn’t stop it inspect your inlet screen.

[M20F-1968]

I have some new news on my oil pressure issues.  I spoke with PenYan who initially worked on my engine.  We spoke generally about the problem.  They focused on the need for a source of resistance in the turbo line.  I already have a pressure relief valve.  I also spoke with Lycoming and other engine shops and they concentrated on the pressure relief valve.  We installed a new spring in the pressure relief valve (2 springs stronger than the one that was producing 60 psi)  one washer.  I new get 95-100 on start-up.  When 150 degrees oil temp, running 2400 RPM on the ground, I get 78 psi.  Given that the initial start-up pressure is so much higher than it was, adjusting the oil pressure relief valve seems to be the answer.  

Changing to the new screw-type oil pressure relief valve will probably do nothing, but install a part that 1) could change adjustment as the screw is only held with a lock nut, 2) has the potential of leaking.  I think if I had the screw-type, i would change it for the washer type.

 

[MikeOH]

7 hours ago, N201MKTurbo said:

I have found if it twitches, you are drawing air into the pickup. Whenever a bubble is sucked in it causes the twitch. Try adding more oil. If that doesn’t stop it inspect your inlet screen.

Thanks; I'll try running 7 quarts, as I normally keep it at 6.

Also, pardon my ignorance but where is the inlet screen?  I believe there's a screen near/part of the oil filter adaptor, but is that the one you're referring to?

[N201MKTurbo]

19 minutes ago, MikeOH said:

Thanks; I'll try running 7 quarts, as I normally keep it at 6.

Also, pardon my ignorance but where is the inlet screen?  I believe there's a screen near/part of the oil filter adaptor, but is that the one you're referring to?

No, it is behind a plug down by the bottom of the sump. It is kind of hard to get to. You should work with your mechanic the first time you check it. You have to replace the gasket and lock wire it when you are done. 

[Guest]

29 minutes ago, MikeOH said:

Thanks; I'll try running 7 quarts, as I normally keep it at 6.

Also, pardon my ignorance but where is the inlet screen?  I believe there's a screen near/part of the oil filter adaptor, but is that the one you're referring to?

This picture is from someone on MS.  I circled the suction screen.  It is under the 5/8” nut on the back right side of the oil sump.

Clarence

[MikeOH]

11 minutes ago, M20Doc said:

This picture is from someone on MS.  I circled the suction screen.  It is under the 5/8” nut on the back right side of the oil sump.

Clarence

Perfect!

Thank you!

Do I have to drain the oil to inspect, or is it above the oil level in the sump?