Lose of Prop control-Lycoming (L)TIO-540-V2AD

[rohit]

This is not on a mooney, but on a Lycoming engine (L)TIO-540-V2AD

During prop check : left engine shut down and prop feathered.

We checked dome pressure it was low. fixed that problem. took off and flew for an hour.

landed and during taxi the left engine feathered and shut down.

governor was taken out and found to be perfectly ok

pressure checks : low like 2 psi.

 

What do i do next.

[MB65E]

Hi welcome!! Strange first post but that's ok!! 

Low oil P on the engine during Taxi? Low pitch lock stops worn or damaged?

Whats it on? a Duke? 

-Matt

[N201MKTurbo]

1 hour ago, rohit said:

This is not on a mooney, but on a Lycoming engine (L)TIO-540-V2AD

During prop check : left engine shut down and prop feathered.

We checked dome pressure it was low. fixed that problem. took off and flew for an hour.

landed and during taxi the left engine feathered and shut down.

governor was taken out and found to be perfectly ok

pressure checks : low like 2 psi.

 

What do i do next.

Is your engine oil pressure OK? Is it dropping to a low value at idle? Something is causing the prop governor to starve for oil at idle.

You should post this in the Multi-engine section...

[rohit]

2 hours ago, MB65E said:

Hi welcome!! Strange first post but that's ok!! 

Low oil P on the engine during Taxi? Low pitch lock stops worn or damaged?

Whats it on? a Duke? 

-Matt

its a piper mojave. the mechanic did this  test (described below) and said the pressure was around 2 psi. the engine was rebuilt about 9 months ago and the plane has flown only 50 hours since. then. I am not convinced this is related to oil transfer problem ( of course more $$$) and because engine was recently done. Governor checked out ok at the shop.

To check for this problem, the prop governor must be removed. Use shop air and an air gun with the rubber tip inserted into the prop transfer hole in the governor pad. Put full shop pressure on this transfer hole until all the oil is blown out of the main bearing (no gurgling is heard). When you start this you should notice the prop blades go to immediate high-pitch setting on singles or against the low-pitch stop on most twin-engine governors.

If you want to kill two birds, you can just pull the prop governor and do this check, seeing if the blades go to high pitch, checking for hydraulic lock, sticky blades, and blowing all the oil out of the bearing at the same time. You'll have to do this two or three times so that the oil will be removed from the prop dome. Caution: Do not pull the rubber tip out of the hole until all the pressure inside the prop dome is released. If you do, you will be covered with a huge spray of oil. Also note it should only take about 30 to 40 psi for the prop to go to its pitch stop.

Now hook up a compression tester to the shop air hose and the rubber-tipped air gun to the compression tester instead of a cylinder fitting. Set the compression-tester regulator to 80 psi, as you would for cylinders. With the rubber tip held up in free air, activate the air gun. Make sure that the source gauge reads 80 psi and that the cylinder-side gauge reads zero, with all air escaping from the air gun. Now, put the air-gun rubber tip back in the oil-transfer hole and fully activate it. The only air leakage should be a small amount from the transfer point.

Set the compression tester to 80 psi and read the cylinder-side gauge. On a Lycoming, the pressure held by the main bearing should be between four and 20 psi. The low figure here is a little hard to see sometimes, especially with some gauges starting at 10 or so. One reason a Lycoming transfer system can go so low is the engine operating oil pressure. They run between 60 and 90 psi, which aids in lessening the oil leakage from the transfer region in the center of the front main bearing.

A Continental should be no less than 40 for the engines with transfer collars. For the Continental engines with the transfer in the main bearing, the cylinder-side gauge should be no lower than 18 psi. If the cylinder-side gauge falls out of these specs (on the low side), then the transfer system is bad and the engine must be disassembled. If this is not the problem, the governor should be sent off for a thorough bench check.

[N201MKTurbo]

So it looks like you have excessive leakage at the front main bearing. Bummer.

[carusoam]

Welcome aboard Rohit.  What brings you here?

+1 on an internal oil leak, as Rich has suggested.

There seems to be a need to find where that leak is...

 

Put this one idea through the wringer... (based on blended Mooney, and Missile experience that uses an IO550 engine from a twin, then, including some O360 experience...)

1) When the plug at the front of the crank shaft leaks oil, or falls out...

2) The governor's oil pump has no way to keep up with the flow needed to generate pressure.

3) all the bench tests of the governor will be good, but it still doesn't work on the engine...

4) No pressure in the crank, results in the engine going into feather.

5) check the Lycoming site for procedure to test these systems looking for the crank plug.

6) the plug is simply an aluminum disc, that gets hammered into the end of the crank.

7) real life experience: My Lyc. O360 lost this plug once.  My friend found instructions from the EAA on how to test  the system. It required machining a block with holes with the right detail, in the right places. Or just removing the prop and inspect.

8) To reset the 50cent plug, the prop has to come off.

9) I OH'd the governor because it needed it.  But it wasn't the issue.

10) flying without an operating governor in an M20C leads to reving past rpm limits as its prop hits the dminimum stops and doesn't come off them...

11) in your case and the Missile would do this as well... the lack of oil pressure leads to a feathered condition supplying no thrust.

12) check your governor's oil supply lines to the prop. If they are done the same way as the O360, an internal oil leak is probably occurring and dumping the oil and its pressure back into the sump...

13) pulling off the prop is really low cost compared to replacing a leaking main bearing.  Either way the prop is coming off for access.

This is PP advice only, not a mechanic at all.

How does that sound?

Best regards,

-a-

[rohit]

58 minutes ago, carusoam said:

Welcome aboard Rohit.  What brings you here?

+1 on an internal oil leak, as Rich has suggested.

There seems to be a need to find where that leak is...

 

Put this one idea through the wringer... (based on blended Mooney, and Missile experience that uses an IO550 engine from a twin, then, including some O360 experience...)

1) When the plug at the front of the crank shaft leaks oil, or falls out...

2) The governor's oil pump has no way to keep up with the flow needed to generate pressure.

3) all the bench tests of the governor will be good, but it still doesn't work on the engine...

4) No pressure in the crank, results in the engine going into feather.

5) check the Lycoming site for procedure to test these systems looking for the crank plug.

6) the plug is simply an aluminum disc, that gets hammered into the end of the crank.

7) real life experience: My Lyc. O360 lost this plug once.  My friend found instructions from the EAA on how to test  the system. It required machining a block with holes with the right detail, in the right places. Or just removing the prop and inspect.

8) To reset the 50cent plug, the prop has to come off.

9) I OH'd the governor because it needed it.  But it wasn't the issue.

10) flying without an operating governor in an M20C leads to reving past rpm limits as its prop hits the dminimum stops and doesn't come off them...

11) in your case and the Missile would do this as well... the lack of oil pressure leads to a feathered condition supplying no thrust.

12) check your governor's oil supply lines to the prop. If they are done the same way as the O360, an internal oil leak is probably occurring and dumping the oil and its pressure back into the sump...

13) pulling off the prop is really low cost compared to replacing a leaking main bearing.  Either way the prop is coming off for access.

This is PP advice only, not a mechanic at all.

How does that sound?

Best regards,

-a-

thanks for the detailed explanation. i will ask my mechanic to do the crank shaft seal check. 

will this cause the pressure test to fail ? how much can a front bearing repair cost on a lycoming ? my governor was accentuating a bit so they did work on it , not a complete overhaul but ' fixed something'

 

 

[carusoam]

1) the front crank seal, with the EAA test block takes hoses that connect the governor's, oil hose pressure and return and connect it to pressurized air to test the function of the prop's actuator.

2) The front bearing probably requires taking the crank out first... a huge undertaking.

What warranty do you have on the overhaul that you mentioned?

Wait for Rich to answer this question, if able...because the front bearing would be indirectly related to the prop's oil pressure leaking out there.  He has the real technical background. 

I only have Private Pilot knowledge...

Best regards,

-a-

[rohit]

9 minutes ago, carusoam said:

The front bearing probably requires taking the crank out first... a huge undertaking.

What warranty do you have on the overhaul that you mentioned?

Wait for Rich to answer this question, if able...because I'm confused with how the front bearing would be related to the prop's oil pressure. He has the real technical background.

I only have Private Pilot knowledge...

 

 

Best regards,

-a-

1 hour ago, carusoam said:

Welcome aboard Rohit.  What brings you here?

+1 on an internal oil leak, as Rich has suggested.

There seems to be a need to find where that leak is...

 

Put this one idea through the wringer... (based on blended Mooney, and Missile experience that uses an IO550 engine from a twin, then, including some O360 experience...)

1) When the plug at the front of the crank shaft leaks oil, or falls out...

2) The governor's oil pump has no way to keep up with the flow needed to generate pressure.

3) all the bench tests of the governor will be good, but it still doesn't work on the engine...

4) No pressure in the crank, results in the engine going into feather.

5) check the Lycoming site for procedure to test these systems looking for the crank plug.

6) the plug is simply an aluminum disc, that gets hammered into the end of the crank.

7) real life experience: My Lyc. O360 lost this plug once.  My friend found instructions from the EAA on how to test  the system. It required machining a block with holes with the right detail, in the right places. Or just removing the prop and inspect.

8) To reset the 50cent plug, the prop has to come off.

9) I OH'd the governor because it needed it.  But it wasn't the issue.

10) flying without an operating governor in an M20C leads to reving past rpm limits as its prop hits the dminimum stops and doesn't come off them...

11) in your case and the Missile would do this as well... the lack of oil pressure leads to a feathered condition supplying no thrust.

12) check your governor's oil supply lines to the prop. If they are done the same way as the O360, an internal oil leak is probably occurring and dumping the oil and its pressure back into the sump...

13) pulling off the prop is really low cost compared to replacing a leaking main bearing.  Either way the prop is coming off for access.

This is PP advice only, not a mechanic at all.

How does that sound?

Best regards,

-a-

thanks for the detailed explanation. i will ask my mechanic to do the crank shaft seal check. 

will this cause the pressure test to fail ? how much can a front bearing repair cost on a lycoming ? my governor was accentuating a bit so they did work on it , not a complete overhaul but ' fixed something'

 

 

[rohit]

http://westernskyways.com/ did the engine in july 2016 . i just bought the plane 3 weeks ago . no problem at pre buy. the previous owner had inflight crank shaft broken and engine shut down. that was all repaired. no cause found. not sure about the details of the warranty yet trying to find out. recently replaced crank shaft makes me suspicious that the valve came off. //??? can a front bearing fail that quickly in 50 hours of flying since overhauls

[carusoam]

Governors have a tendency to have their flyweight operations wear out causing the gov's oil pressure to wander a bit.

This wandering prop oil pressure turns into a wandering rpm.

Other things in the gov that can cause prop oil pressure issues would be it's gear pump, and a conic valve surface.

If the gear pump doesn't pump...no pressure.

if the conic valve sticks...no pressure.

The fly weights directly operate the conic pressure control valve.

Best regards,

-a-

[carusoam]

Somebody has supplied a picture of a failed bearing around here somewhere...just today...

Use the search function to find it...

Their typical failure Mode is lack of oil. Something clogs their tiny oil line. Or being installed backwards misaligning the oil supply to the bearing...

PP thoughts only.  Could be very misleading,,,

Best regards,

-a-

[MB65E]

If the front bearing shifted you'll have some problems. There is close to zero oil pressure at the front crank seal. It's basically runoff crankcase pressure. I would not fly it. Also air pressure on the oil galleys with out oil is a good way to have a bearing shift. I'd be talking to western skyways and making sure your warrantes are transferable. It will be close to $10k by the time you split the case. 

Might see what the delta is between the front oil galley pressure and back oil galley pressure by the pump is. That will tell you if you have enough oil up front to begin with. What was the inflight oil pressure, what was the idle ground running pressure post flight??

Inflight should be close to 90psi I would say. Hot Idle ground pressure should be worst case 50psi. 

-Matt

[MB65E]

Was the governor replaced at the overhaul? That engine puts out some HP!!

-Matt

[carusoam]

Possibly helpful info...

 

LTIO-540

Left-hand (opposite-direction) rotation, turbocharged, fuel-injected; used as the right-hand engine on Piper PA-31-325 Navajo C/Rs and Piper PA-31-350 Chieftains^[4] to prevent critical engine control issues. Also used for the left hand side of the Aerostar 700P.

 

https://www.pennyanaero.com/Piper-PA-31P-350-Mojave-Lycoming-LTIO-540-V2AD-16.php

 

http://westernskyways.com/TIO-540/

 

 

 

-a-

[MB65E]

Thanks A!! You Jogged my memory!!Make sure the correct governors are installed on the correct sides!!! I was involved in fixing a screwed up Seneca that had the wrong governor on the right engine. The part numbers between L&R should be different!!

-Matt

[rohit]

9 hours ago, MB65E said:

If the front bearing shifted you'll have some problems. There is close to zero oil pressure at the front crank seal. It's basically runoff crankcase pressure. I would not fly it. Also air pressure on the oil galleys with out oil is a good way to have a bearing shift. I'd be talking to western skyways and making sure your warrantes are transferable. It will be close to $10k by the time you split the case. 

Might see what the delta is between the front oil galley pressure and back oil galley pressure by the pump is. That will tell you if you have enough oil up front to begin with. What was the inflight oil pressure, what was the idle ground running pressure post flight??

Inflight should be close to 90psi I would say. Hot Idle ground pressure should be worst case 50psi. 

-Matt

Thanks Matt, So I have a mechanic looking at the crank shaft plug today. We will make sure the governor is the right one. When the mechanic put pressure from the governor port to the props to 100 psi it would hold about 14 psi. My thought is its either the plug or the the bearing at this time. Any more thoughts are appreciated

[rohit]

talked to the Western Skyways Eric wants me to do the pressure test on a warm engine > So we have to put the governor back warm up the engine and run the pressure test again. He claims it will read low on a cold engine. So the plan is to put the governor back. Start the engine. Check the Dome pressure Nitrogen. Check Idle engine oil pressures and try do a feather check and see what happens.

Edited July 7, 2017 by rohit

[Cody Stallings]

Sounds like Sticky Latches in the Cylinder.

Its very Common on a feathering propeller.

FJC8468 is a lot of blade to try an hold flat till the latchs close at shutdown.

 

Also, if your servo is allowing your engine to idle to slow, this problem will surface too.

The props counterweight, Spring an Nitrogen charge are all pushing it towards Feather, with a weak idle oil pressure the propeller will be victorious in its quest to Feather