N2652W will have a new home!

[carusoam]

A bad main would be oil leaking through the system so quickly, pressure doesn’t build...

But that would be the oil pressure in the engine...

If we are still talking governors and props...

The govenor has its oil pick-up

its own gear pump

its own control valve

its fly weights to control the conic shaped control valve...

It sends pressurized oil towards the prop... and returns it through the hoses externally...

There are two ways that oil pressure doesn’t reach the prop... documented around here...

The shaft seal gets dislodged... the crankshaft is hollow.... prop on one end... aluminum disc closing off the other end...

Somebody documented a set screw in the same area... their set screw was never put in place and the oil pressure leaked back to the case...

Other than that we would be questioning if the gov’s gear pump is generating pressure, or the control valve is stuck open dumping the pressure...

Good luck with your next steps... I’m sure I missed something... 

Best regards,

-a-

[hammdo]

Plug in the crank is solid - no screw - AP checked

oil pressure has been in the green and in the lycoming recommend range

gov itself has been inspected and tested - same with the prop

gov cycles prop during run-up reasonably quick

so, we can ck the plug in the shaft again to be 100% sure

pressure test is next if this acts the same during flight test

-Don

 

[hammdo]

Found this in my search on MooneySpace for possible prop pressure issues. Process seems simple with the prop off;

It turned out to be a defective installed plug in the crankshaft.  We were able to diagnose the problem by exerting a small amount of pressure in the crankcase pressure relief port.

 

The steps below are what we followed to determine the issue.

 

First, we did the SI 1462A after validating the governor was good.  Test showed issue with loss of pressure. Then, to diagnose the problem (main bearing vs plug), exert a small amount of pressure in the crankcase pressure relief port.

 

The Lycoming SI 1462A will usually be the first thing to do but, if you've inspected the governor and prop, you may want to verify the crankplug if the prop is off before doing the SI since you need an adapter plate (create or purchase) to do the SI.

 

Lycoming engineers provide four potential causes for loss of prop control (lease to most expensive option):

 

1.       A plug located in the crank has become lose and needs to be replaced (remove prop and observe for leakage)

 

2.       The transfer collar needs to be rebuilt (if installed)

 

3.       A piston which controls prop pitch has oil on both sides and needs to be rebuilt.

 

4.       Engine - Front main bearing needs to be replaced – there is a relationship to the front bearing and the oil supply to the governor.

 

The issue is you can't easily determine if the plug is leaking without pressure.  So slowly apply up to 25 PSI max of air pressure. Use a small rubber adaptor to plug into the crankcase breather vent port and any other openings that vent the crankcase. Slowly add pressure and observe if any oil/air/bubbles leak around the plug.  

 

Don't add too much pressure to the engine - limited the test to 25 PSI Max.'

Parts catalog for 0360...

https://www.lycoming.com/sites/default/files/O-IO-HO-HIO-360 Parts Catalog PC-106.pdf

Looks like a simple plug in the back of the crank (noted earlier) could still leak pressure even if the plug looks set.

Part is:

61510

-Don

[carusoam]

Interesting list Don...

Where the oil pressure hoses deliver oil to the nose can have some additional pressure losses if something wears...

Got drawings of the crank showing how oil gets to the center of the shaft?

If it runs out, into the case... pressure won’t get to the prop...

I think that is #2, the transfer collar they are referring to.

 

I haven’t heard of one not working properly, that I can remember...

Cody can give the most insight on the piston that controls the blade angle... a leaky seal there is probably more common than the other things...

Best regards,

-a-

[hammdo]

Prop has been looked at and checked out good. While the prop is off, good idea just to make sure the plug is not leaking by doing a quick pressure test...

after that, test fly and see...

-Don

[hammdo]

So, just an update for those following:

Charles (AP at Air-O Specialist) was following the pressure test noted above but instead of air pressure, used a smoker (pretty sharp of him). Found out immediately that the plug in the crank-prop rear of the crank was really smoking around the plug!

My guess is the plug has fatigued enough to leak pressure. So,  Charles is checking with their engine shop for a safe way to replace the plug..

As part of my research, I reviewed the IRAN work done in 2005 (have the papers) and nowhere did it note a new crank plug (61510) installed. I really suspected the plug but had to find a way to verify it. The RV builders site and MooneySpace helped me do that (RV folks love the o/io-360). Learned a lot about the plugs - o-A1D, o-A1A have solid plug, io-A1A has the one with the removable plug in the center for fixed pitch props - in most cases (different tapers and size). Of course more have either but the Lycoming IPC above notes that.

Fingers crossed...

-Don

[hammdo]

Plug ordered:

we'll see how it goes...

-Don

 

[EricJ]

7 hours ago, hammdo said:

So, just an update for those following:

Charles (AP at Air-O Specialist) was following the pressure test noted above but instead of air pressure, used a smoker (pretty sharp of him). Found out immediately that the plug in the rear of the crank was really smoking around the plug!

My guess is the plug has fatigued enough to leak pressure. So,  Charles is checking with their engine shop for a safe way to replace the plug..

As part of my research, I reviewed the IRAN work done in 2005 (have the papers) and nowhere did it note a new crank plug (61510) installed. I really suspected the plug but had to find a way to verify it. The RV builders site and MooneySpace helped me do that (RV folks love the o/io-360). Learned a lot about the plugs - A1D has solid plug, A1A has the one with the removable plug in the center for fixed pitch props - in most cases (different tapers and size). Of course more have either but the Lycoming IPC above notes that.

Fingers crossed...

-Don

Nice!

I'm a little confused about how you spotted the smoke, though.   Where did the smoke go in and where did you see it come out?

 

[hammdo]

Crankcase vent was the inlet, blocked the upper crankcase vent, filled the crankcase with smoke from the lower vent, watched the plug to see if any smoke came out of the plug.

It appears the smoke made its way into the crank and out the plug... AP said it was really clear where the smoke came from...

Example pic of the plug in the crankshaft: (O-360-A1D)

-Don

[EricJ]

32 minutes ago, hammdo said:

Crankcase vent was the inlet, blocked the upper crankcase vent, filled the crankcase with smoke from the lower vent, watched the plug to see if any smoke came out of the plug.

It appears the smoke made its way into the crank and out the plug... AP said it was really clear where the smoke came from...

Example pic of the plug in the crankshaft: (O-360-A1D)

-Don

 

Makes sense.

When mine was having trouble my IA told me had a case where the overhaul shop had installed the plug a bit too far back and it was leaking out the back of the snout into the crankcase around the plug.   Evidently they fixed it in place once they figured out what was going on.

The smoke trick is clever.   That would have made it evident if it was leaking around the bearings, too, so it's a nice way to isolate it.

 

[hammdo]

Yep, safer too...

-Don

[EricJ]

Just now, hammdo said:

Yep, safer too...

-Don

And it can be done with the prop off!   So that's handy when that's the case.

 

[hammdo]

I would guess the smoke could help with oil leaks or cracked case too...

-Don

[carusoam]

Don,

Thanks for the continued sharing of all the details...

Great pics...

Best regards,

-a-

[hammdo]

So, if you've been following along, I have great news!

For those in a hurry, the new crank plug FIXED the prop issue!  Yep, a $15 crank plug caused the prop to not change pitch

For a bit more info, read below...

The video evidence:

Bad crank plug (using the pressurized smoke machine):

After the crank plug was replace (using the pressurized smoke machine again):

 

Video quality is not the greatest but, you get the idea!

So, using the steps I listed above (except using a smoke machine thanks to Charles at Air-O Specialist) we were able to find the 'smoking gun' - literally.

How about that folks!

Now, Lycoming said if its in the 'oil transfer system', send the engine to them -- I didn't like that idea. So if doing the SI 1462A and it reveals an issue with the crank, DO THIS before anything else.  I spoke with Charles and we removed the prop and had it inspected by Byam's, just to be sure the prop was good after sitting so long -- no issues at all!  

Too many folks send in their engines and have an overhaul due to this issue - AND STILL have this issue BTW...

Now, in my research it appears this raises its ugly head ~600 since field overhaul/rebuild (in my case, IRAN).  Several folks who had overhauls or rebuilds found this plug was NOT replaced and caused CS prop issues so, always make sure its replaced (there are different plugs for constant speed props in Lycomings so review the IPC for your engine).

I know of a Bravo in 2011 that was a Lycoming 540 that had this issue and was fixed by replacing the crank plug (~600 hrs since overhaul/rebuild).  RV's folks have had several of them for the O and IO 360 -- same issue.

I did a 1 hour maintenance flight above the airport and it was great -- the max RPM is still a bit low so that will be adjusted but, the prop can now change its pitch.

So after IRAN of governor, simple check of the PROP function (IRAN), this was the issue.

BTW, the AP (Charles) plugged all openings for the crankcase -- including the governor oil tube in the upper part of the case -- to eliminate that as a factor.

FYI, Charles also informed me the engine shop said never reuse these plugs or even try to tap them back in. When their done, that's it..

Whew....

@Sabremech @Cody Stallings @M20Doc

Figured you might find this interesting...

EDIT:

I think I'll call this SI 1462B - crank plug vs main bearing test ;o)

-Don

[carusoam]

Don,

Thanks for the continued sharing of all the details...

Great Videos this time!

Best regards,

-a-

[hammdo]

Glad too. Hopefully, this will save someone from yanking a good running engine for inspection...

-Don

[hammdo]

Just so folks know, the cross tube in the crank pic with the cut out is there for a reason for CS props:

A longtime Lycoming engineer explained that without the cross tube, there is no way to get air out of oil. When the crank is spinnning the oil goes to the outside, due to weight, air to center, exactly where slot/hole is in the cross tube.

-Don

[hammdo]

BTW @carusoam, you mentioned the plug in other threads too (not just mine).  Finding a way to verify the plug was really scarce.

Thanks for reiterating that here about the plug...

Helped me in my search...

-Don

[hammdo]

Just an update:

Doing maintenance flights while we tweak the max RPM. We're finding the analog tach vs AP's digital tach RPM tool is showing the RPM reads lower on the analog tach vs the digital tach. So my new normal on the analog tach will be 2650 RPM is Redline now. I'll placard that but she's flying great. One more maintenance flight and she'll be ready for some cross country trips! 

-Don 

[carusoam]

Don,

EI makes a nice individual tach instrument if interested...

-a-

[hammdo]

I have to recover a bit first after these last upgrades/fixes. Have a couple of other things planned first but a digital tach will be one of the first couple of items... 

-Don 

[hammdo]

3 maintenance flights and she's good to go! Have my new normal reading (just above 2600 on the mechanical tach). She's flying great, hit 100° on the field today and she handled that with no problem. 

Signed up for the PPP and getting ready now. That will be challenging and fun for June here in Texas ;o)

Looking over the worksheet, some info not in the manuals... looking at the last release C manual to find some of this...

-Don

[hammdo]

Made it to Alliance today for the MSF training session. I'll keep it @ AFW so I can avoid extra drive/flight. Very excited about the course. Made some sun shades to keep the heat out... 

 

-Don 

[hammdo]

So, the MSF was fantastic. I had the fortune to have Jerry Johnson as my CFI for the flight sessions. That was fun - he helped work the rust off for sure.

@Sabremech, folks loved the cowling and, they want to contact you about the new version ;o)

Jerry could not believe how fast 2652W is (Jerry has a 69 C). Someone at the dinner ask him if mine was faster than his and, without hesitation, said 'gosh yes!'

Lots of great pilots and instructors were there. I enjoyed my time and realize I need to get better and spend more time with 'Mooney specific CFI's' ;o).

Worth the $.

Alliance and Alliance Aviation were great hosts. 
 

-Don