Push Rod Seals

[T. Peterson]

5 hours ago, Shadrach said:

Offering a critique of Clearance’s maintenance opinions is well above my pay grade. I don’t think he was diagnosing your specific engine so much a offering a known cause or recurring leaks. Does your engine exhibit any other symptoms of excessive case pressure?   SB M89-9  covers how to test crankcase pressure with a manometer or an old airspeed indicator.  The maximum acceptable reading for your engine at full power is 4.00” H2O or 90MPH indicated.

Several of my pushrod seals are weeping as well, but their sub optimal condition can verified visibly. They’ll be replaced at annual in October. 
 

 

You and Clarence have both told me of a way to measure the internal pressure. None of my attending shops have mentioned that procedure, or that high internal pressure could be the cause. Therefore I will humbly nudge them in that direction. 
I am grateful to both of you.

[T. Peterson]

21 hours ago, 1980Mooney said:

That's interesting.  The Lycoming IO-360 in my 1980 J was rather leak prone.  I can't recall the specifics now but it seemed like we were always chasing a leak .  However after my Missile conversion to a Continental IO-550 I have not experienced any leaks in 22 years.  It has been tight.  The only time I see oil is if I overfill the oil fill pipe by pouring too fast or carelessly.  Perhaps the Continental IO-360 is more trouble prone.

Now I am coveting your IO-550 for more than one reason!!

[LANCECASPER]

On 3/11/2023 at 11:12 AM, T. Peterson said:

The engine was installed new in 1991. It has 1300 hours on it.

How many hours on the cylinders?

[T. Peterson]

2 minutes ago, LANCECASPER said:

How many hours on the cylinders?

The same. Pre buy tech said they were fine.……But, I suppose a top is needed. Oh well, life has a few surprises. Sometimes a fella just has to assess, adapt and overcome!

[Shadrach]

20 minutes ago, T. Peterson said:

Now I am coveting your IO-550 for more than one reason!!

I don’t think that one make/model of engine is inherently oil tight over another. The quality and age of the assembly are bigger factors. Seals can deform and deteriorate over time. Properly joined case halves can last nearly a lifetime. 

[Shadrach]

10 minutes ago, T. Peterson said:

The same. Pre buy tech said they were fine.……But, I suppose a top is needed. Oh well, life has a few surprises. Sometimes a fella just has to assess, adapt and overcome!

Whoa…let’s not start writing off cylinders just yet. Maybe verify that case pressure is an issue.

[T. Peterson]

1 minute ago, Shadrach said:

Whoa…let’s not start writing off cylinders just yet. Maybe verify that case pressure is an issue.

Good point. I am about to share some of these ideas with Granbury Aviation Services (Don Maxwell has an ill mechanic that has put them behind.).

 I hope the gentleman at GAS knows how to measure internal case pressure. 

[carusoam]

11 minutes ago, T. Peterson said:

Good point. I am about to share some of these ideas with Granbury Aviation Services (Don Maxwell has an ill mechanic that has put them behind.).

 I hope the gentleman at GAS knows how to measure internal case pressure. 

case pressure is an easy one!

It usually uses an air pressure gauge put on the oil fill tube in replacement of the oil cap that is usually there…

Some specs are written that an airspeed indicator gets used as a pressure gauge…

 

Torrey,

See if you can update your profile with some specs and a pic…

I forgot which plane we were discussing, and can’t see your details….

It helps a lot to know what year, model, and other details that you can put in there…

Best regards,

-a-

[Shadrach]

17 minutes ago, carusoam said:

case pressure is an easy one!

It usually uses an air pressure gauge put on the oil fill tube in replacement of the oil cap that is usually there…

Some specs are written that an airspeed indicator gets used as a pressure gauge…

 

Torrey,

See if you can update your profile with some specs and a pic…

I forgot which plane we were discussing, and can’t see your details….

It helps a lot to know what year, model, and other details that you can put in there…

Best regards,

-a-

It’s a 1979 231 that was last overhauled in 1991. See his first post.

[Fly Boomer]

16 hours ago, M20Doc said:

Blowby will cause oil to collect on the bottoms of the spring coils.

Okay, I have misinterpreted something prior to this statement.  I thought blow-by was combustion gasses getting past the rings and into the crankcase, thereby creating a (too) high pressure condition.  So, how does that cause oil to collect on the bottoms of the spring coils?  And, is that also the case for a Continental (TSIO-520)?

[hubcap]

I have the TSIO-360-LB engine in my M20K 231 as well. I just had the push rod seals replaced at ~800hrs on this engine during annual. As soon as the avionic upgrade is complete I will be able to tell if it gets rid of my minor oil leak.

[Guest]

1 hour ago, Fly Boomer said:

Okay, I have misinterpreted something prior to this statement.  I thought blow-by was combustion gasses getting past the rings and into the crankcase, thereby creating a (too) high pressure condition.  So, how does that cause oil to collect on the bottoms of the spring coils?  And, is that also the case for a Continental (TSIO-520)?

Higher internal pressure causes oil to seep out past the pushrod tube seals, where it seems to collect on the bottom of the springs.  Other than the small engines through the O-200, they all share the same pushrod tube and seal design.

[Guest]

3 hours ago, T. Peterson said:

You and Clarence have both told me of a way to measure the internal pressure. None of my attending shops have mentioned that procedure, or that high internal pressure could be the cause. Therefore I will humbly nudge them in that direction. 
I am grateful to both of you.

From the SB that Ross posted, they suggest using the old timing port as an access point.  The shop will need a spare plug drilled and thread tapped to connect to the airspeed indicator or water manometer, or an old oil cap with a fitting welded to it.

I was tired when I posted the 16” of water, 4” is correct.  Water value is the square of airspeed, 4” water equals 90 mph, 180mph equals 16” of water.

[Guest]

This is from a TSIO550K in a Cirrus, but they’re all the same basic design.   The white seal is compressed between two washers, the O ring fits in a counterbore in the cylinder head.

[T. Peterson]

1 hour ago, M20Doc said:

This is from a TSIO550K in a Cirrus, but they’re all the same basic design.   The white seal is compressed between two washers, the O ring fits in a counterbore in the cylinder head.

I really appreciate this picture! Thanks to you good people I am getting an education. 

[T. Peterson]

6 hours ago, carusoam said:

case pressure is an easy one!

It usually uses an air pressure gauge put on the oil fill tube in replacement of the oil cap that is usually there…

Some specs are written that an airspeed indicator gets used as a pressure gauge…

 

Torrey,

See if you can update your profile with some specs and a pic…

I forgot which plane we were discussing, and can’t see your details….

It helps a lot to know what year, model, and other details that you can put in there…

Best regards,

-a-

So let it be said, so let it be done!

Torrey

[T. Peterson]

So, I visited with my mechanic today and expressed my concerns about internal case pressure. He did not think that high case pressure would necessarily show up as leaking push rod seals. He said it would more likely show up through the crank case breather. He asked me to send him my compression values from the September annual. Two were at 70, one was 68, one 66 and the #2 cylinder was 56. I remember reading that Continental pressure in the 50’s was not a big concern and I tried to convey that to him. He seemed to think that if one was more than 10psi different from the others it was a problem. This discussion occurred before I actually looked up the numbers and sent them to him, so hopefully I will find out tomorrow what course of action he recommends. I just want the leak fixed. 

[Old Chub]

Although not the same engine but similar construction I chased pushrod tube leaks on a C-182 with an O-470.   Tried new seals and even the Real Gaskets seals were not working with a couple of tubes.   One engine builder told me to check for the tubes being out of round.   Sure enough the tubes that I could not seal had somehow gotten out of round either due to mishandling during previous cylinder removal or maybe previously chasing push rod shroud leaks.  Might be worth a look to roll the tubes in a set of V blocks to check if there is any out of round on seal surface area if you have a particularly stubborn push rod shroud leak on your continental.   

 

[Will.iam]

On 3/13/2023 at 9:09 PM, T. Peterson said:

So, I visited with my mechanic today and expressed my concerns about internal case pressure. He did not think that high case pressure would necessarily show up as leaking push rod seals. He said it would more likely show up through the crank case breather. He asked me to send him my compression values from the September annual. Two were at 70, one was 68, one 66 and the #2 cylinder was 56. I remember reading that Continental pressure in the 50’s was not a big concern and I tried to convey that to him. He seemed to think that if one was more than 10psi different from the others it was a problem. This discussion occurred before I actually looked up the numbers and sent them to him, so hopefully I will find out tomorrow what course of action he recommends. I just want the leak fixed. 

Torrey first off go cheapest option first. That #2 cyl could easily be the rings lined up their gaps perfectly on shutdown. I would fly the airplane around the pattern then come back and get the compression reading on #2 cyl first. If it has not risen into the 60’s then i would borescope that cylinder and look closely at the exhaust valve also listen to where the air is escaping when the compression test is being done as most likely the exhaust valve is not seating well and would need to do a valve lapping in place. These are much cheaper options before pulling a cylinder but if the compression is still low then it could be the cylinder that is causing higher than normal blow-by. 

[T. Peterson]

5 hours ago, Will.iam said:

Torrey first off go cheapest option first. That #2 cyl could easily be the rings lined up their gaps perfectly on shutdown. I would fly the airplane around the pattern then come back and get the compression reading on #2 cyl first. If it has not risen into the 60’s then i would borescope that cylinder and look closely at the exhaust valve also listen to where the air is escaping when the compression test is being done as most likely the exhaust valve is not seating well and would need to do a valve lapping in place. These are much cheaper options before pulling a cylinder but if the compression is still low then it could be the cylinder that is causing higher than normal blow-by. 

Thanks Will,

that is excellent advice…..if I can find a mechanic with time to work on it! I am waiting on two to call me back. I gave them both plenty of lead time but it’s just crickets. I think they are all so busy they can cherry pick the jobs they want to do and avoid the more difficult. 
I may have to re-think working on my own plane but I will have to buy a bunch of equipment. I retire in the fall, maybe I should go to A&P school!!

 I may not be able to fix my airplane but so far the Pros are 0/4.

[Guest]

8 hours ago, T. Peterson said:

Thanks Will,

that is excellent advice…..if I can find a mechanic with time to work on it! I am waiting on two to call me back. I gave them both plenty of lead time but it’s just crickets. I think they are all so busy they can cherry pick the jobs they want to do and avoid the more difficult. 
I may have to re-think working on my own plane but I will have to buy a bunch of equipment. I retire in the fall, maybe I should go to A&P school!!

 I may not be able to fix my airplane but so far the Pros are 0/4.

The guy who mentioned the difference in pressure readings is using Lycoming values on your Continental.

[T. Peterson]

1 hour ago, M20Doc said:

The guy who mentioned the difference in pressure readings is using Lycoming values on your Continental.

Wow! What a procedure! No wonder nobody calls me back!

Well that is certainly above my pay grade. I will have to wait till a shop is willing to work on it or I graduate from A&P school! LOL!

The engine runs great. I just flew Ennis, Texas to Wichita, Kansas yesterday and heading home today. So I guess I will just continue to march and keep trying to get the airplane seen. 

 I so very much appreciate you taking the time to respond and post this procedure. At least I am armed with needed information and can hopefully discern with a few gentle questions the procedural intentions of any given shop.

Thank you 

[Will.iam]

5 hours ago, T. Peterson said:

Wow! What a procedure! No wonder nobody calls me back!

Well that is certainly above my pay grade. I will have to wait till a shop is willing to work on it or I graduate from A&P school! LOL!

The engine runs great. I just flew Ennis, Texas to Wichita, Kansas yesterday and heading home today. So I guess I will just continue to march and keep trying to get the airplane seen. 

 I so very much appreciate you taking the time to respond and post this procedure. At least I am armed with needed information and can hopefully discern with a few gentle questions the procedural intentions of any given shop.

Thank you 

Hey torrey i talked to a neighbohr that uses tim fellegy  (940) 442-5232 up at denton airport and said even though he is busy with annuals, he is good about getting in people in between the annuals. He maintains the family’s mooney. Might be worth a call. 
 

[Fly Boomer]

@M20Doc Clarence, those pages you provided above are from the M-0 manual?

[Guest]

11 minutes ago, Fly Boomer said:

@M20Doc Clarence, those pages you provided above are from the M-0 manual?

Yes.  The same procedure as the old SB03-3.