51 year old prop governor?

[stevebennett327]

   I recently purchased a 64 e model. It was only flown 8 hours in the last 20 months before my purchase. I have flown it 40 hours in 3 months since buying it and it has taken on some oil leaks. It's had several trips to the mechanic then I fly it and a few more things start leaking. It started leaking heavily after a 3 hour cross country flight to Atlanta. It was dumping a quart an hour. I just had the prop governor removed and the gasket replaced and it got a little better. The mechanic said that he tightened slightly the bolts on the gov and that it might be leaking from a seal that he can't change. I called a prop shop today and they suggest just scrapping the old governor without even bench testing it. I said it works fine it just leaks oil. I've ordered a new governor but while I was ordering I said to myself that I was going to post my problem here and see if other members here think I did the right thing.  Ok, let me have it. I spent 1764 dollars on a new one before install. Steve Bennett 1964 M20E

[N201MKTurbo]

If it is a Hartzell H1 it is probably leaking from the oil pump gasket. They will leak like crazy when they go bad. The seal is cheap and easy to change if you can get a prop shop to IRAN it.

[orionflt]

the problem with the older governor is lack of parts if they need more then seals. It is defiantly worth having it opened up and looked at but if it needs flyweights you might as well just replace it with a PCU5000

Brian

[cliffy]

Min hadn't been looked at in 20 plus years when I went for overhaul. Took some parts to get it right again.  

Like mentioned, some parts can be hard to get if needed.

One gov is a small price to pay for a good buy on a Mooney. I always figure 15% of what I pay for an airplane will go into it in the first 2 years getting it to where I want it mechanically. 

Even the cheap b$%^&*ds club has limitations.

Low use doesn't necessarily mean "perfect condition".

[MB65E]

+2 on the pcu5000

-Matt

[Alan Fox]

If it fails and overspeeds , you could be looking at an engine.....Don't overthink it....

[stevebennett327]

Thanks for your honest thoughts everyone, The PCU is the one I bought. I agree that "Low use" isn't a good thing. To elaborate further the thing was only flown 80 hours in 10 years. I'm sure that's why all the oil leaks. But hey, we are getting the bugs worked out. Steve Bennett

[N601RX]

My pcu5000 works great and saves a few lbs also. It is also much smaller and gives a little more hand room to access the rear of the engine. You will have to change the 4 mounting studs to install it.

[rbridges]

Thanks for your honest thoughts everyone, The PCU is the one I bought. I agree that "Low use" isn't a good thing. To elaborate further the thing was only flown 80 hours in 10 years. I'm sure that's why all the oil leaks. But hey, we are getting the bugs worked out. Steve Bennett

 

it's nice that the plane was bought by someone who will actually fly it.  

[HRM]

My prop started drifting and I was getting tired of doing the hub ECI checks so I just had the whole thing overhauled, which had not been done for over 30 years. The prop came back like new, the hub is now full of red oil that if cracks develop will be noticeable at annual (no more ECI) and the governor was O/H'd and now it sits wherever I put it.

 

With an old Mooney you want everything forward of the firewall robust. Shoot, I guess you want that with any airplane 

[kortopates]

Thanks for your honest thoughts everyone, The PCU is the one I bought. I agree that "Low use" isn't a good thing. To elaborate further the thing was only flown 80 hours in 10 years. I'm sure that's why all the oil leaks. But hey, we are getting the bugs worked out. Steve Bennett

I hope you're aware of engine corrosion risk issues from a plane that likely sat longterm and either got a very thorough PPI on it or valued it as a runout engine. Don't mean to sound doom and gloom but the oil leaks and governor may be the least of your concern if there is internal corrosion. If there is, it typically shows up 1.5 to 2yrs after being put back into normal use with spalling cam and lifters. Good to have a plan.

Sent from my iPhone using Tapatalk

[1964-M20E]

Well I found my oil leak yesterday.  Was experiencing  about 1 qt every 4 to 6 hours and the bottom of the plane was quite dirty.  I cleaned the engine and while looking around I noticed one of my oil cooler lines where the fitting goes into the engine was loose so i tightened that with a new crush washer did a run up and noticed that the governor was leaking as well.  So now I guess it is time to replace the governor.

[jetdriven]

Try retorquing the nuts with new star washers first, if that doesn't fix it then change the governor gaskets. You should be able to get the governor out of there without too much trouble. 

[Shadrach]

On May 5, 2015 at 5:12:40 AM, n74795 said:

If it fails and overspeeds , you could be looking at an engine.....Don't overthink it....

I'm trying to understand how a failure would result in an overspeed. Can you explain?

[Alan Fox]

10 hours ago, Shadrach said:

I'm trying to understand how a failure would result in an overspeed. Can you explain?

The governor limits the prop speed by applying oil pressure to the propeller piston , the relaxed state is in the low pitch mode , In cruise at 75% if the prop goes full low , you overspeed to god knows what rpm......there will be major stresses to the engine from harmonics , as well as overspeed , you can also have a prop failure (blade) , which will cause the engine to separate from its mount and most likely the airplane.....    Prop governors are a major concern when it comes to single point failures...

[Bob_Belville]

13 minutes ago, n74795 said:

The governor limits the prop speed by applying oil pressure to the propeller piston , the relaxed state is in the low pitch mode , In cruise at 75% if the prop goes full low , you overspeed to god knows what rpm......there will be major stresses to the engine from harmonics , as well as overspeed , you can also have a prop failure (blade) , which will cause the engine to separate from its mount and most likely the airplane.....    Prop governors are a major concern when it comes to single point failures...

That's not my understanding. I believe complete failure mode is low pitch but that there is a mechanical(?) stop that limits rpm to 2700 (or whatever it is set to).

[Shadrach]

21 hours ago, n74795 said:

The governor limits the prop speed by applying oil pressure to the propeller piston , the relaxed state is in the low pitch mode , In cruise at 75% if the prop goes full low , you overspeed to god knows what rpm......there will be major stresses to the engine from harmonics , as well as overspeed , you can also have a prop failure (blade) , which will cause the engine to separate from its mount and most likely the airplane.....    Prop governors are a major concern when it comes to single point failures...

Yes, I understand this, but prop governors don't produce oil pressure,  oil pumps do. If you've lost all pressure to the prop in cruise, you likely have bigger problems. I cannot fathom a governer going from allowing adequate pressure to allowing none...instantly. That was the failure mode I was interested in.   

[N201MKTurbo]

When I was a kid I was out playing Vomit Comet with the Mooney. When you go weightless at the top of the arc you lose oil pressure (because all the oil is at the top of the engine) and the prop goes over speed (Oh $h;-). 

So, throttle back at the top of the arc and when there is no oil the engine goes over speed.

[jetdriven]

1 hour ago, Shadrach said:

Yes, I understand this, but prop governors don't supply oil, oil pumps do. If you've lost all pressure to the prop in cruise, you likely have bigger problems. I cannot fathom a governer going from supplying adequate pressure to supplying none...instantly. That was the failure mode I was interested in.   

It happened to me in a 182. The engine was making metal and some of that got into the governor and jammed the pilot control valve in an underspeed position which caused it to overspeed.  Pulling the power back to limit rpm it wouldn't really hold altitude.  It was quite sudden though, it was like stepping on the clutch while going uphill in a car. 

[carusoam]

From M20C experience...

 

When the 50 cent aluminum disc seal in the crank shaft lets go it is a complete loss of oil pressure to the prop.

My C had this failure prior to run-up.

Being a young, out of the money, CB, engineer, mechanic wannabe. Taking to the sky made sense, somehow.

full throttle, no govenor, equals overspeed.  Controllable only by throttle at this point.

The govenor got OH'd.  The next run-up/flight was the same....

What I learned...

1) a fifty cent seal can fail.

2) it will cost a lot to replace. Requires removing the prop.

3) if something has failed while on the ground, taking to the sky won't ever make it better.

4) MS is a great place to increase one's Mooney specific knowledge.  I got my lesson on the shaft seal from an EAA member at work.

I would still like to understand why it didn't stop on a mechanical limit the way it did prior to the seal getting loose.  To get full power, it would have been done in an overspeed condition.

shared experience, one data point,

-a-

[DXB]

So...while on the topic, I have what I think is the original Hartzell H-1, which was overhauled in 1997 per the logs.  It seems to work fine, no obvious leak.  Would anyone overhaul or change it in the next couple of years?  Or is this strictly an on condition item?   I did not particularly enjoy reading about the catastrophic failure mode here...

[Shadrach]

25 minutes ago, DXB said:

So...while on the topic, I have what I think is the original Hartzell H-1, which was overhauled in 1997 per the logs.  It seems to work fine, no obvious leak.  Would anyone overhaul or change it in the next couple of years?  Or is this strictly an on condition item?   I did not particularly enjoy reading about the catastrophic failure mode here...

Byron's incident had nothing to do with governor wear. I'm not sure which $.50 seal Anthony is referring to. 

 

[Alan Fox]

My friend had the pin in the flyweight fail (internal gov part) the prop overspeeded so bad , it somehow melted or sheared the teeth off of the flywheel , even worse it was in a Glassair 3 and the plane would not maintain enough airspeed to hold altitude , as far as the 2700 rpm stop , this is at static on the ramp , moving at 150 KTS 200 HP will probably spin that prop at over 5000 RPM.....

[1964-M20E]

22 hours ago, jetdriven said:

.

Try retorquing the nuts with new star washers first, if that doesn't fix it then change the governor gaskets. You should be able to get the governor out of there without too much trouble. 

It is not the gasket next to the accessory case it is the second gasket and from what I heard the governor needs to be overhauled or replaced.  

[jetdriven]

If it's working fine it doesn't need to be overhauled simply because it has to come off for a gasket replacement. Those are two separate issues.