Cylinder Crak and EGT

[brndiar]

Hi 

About 3 Hours after Annual (and 100 Hour Inspektion) I encountered Vibrations in Flight.

The engine (O 360 A1D, on Condition, 17 Years Old  and with 800 Hours) has been checked (in Service), there was found nothing

explaining the Vibrations. Compressions at all cylinder were above 70. By second check was found Crack at 3 Cylinder.

I own mine Bird since February, cca 50 Hours so far.

EGT Sensor is at 3 Cylinder and that Cylinder does not peak first. Most I flew at Peak EGT. All Temperatures were always in Green.

Change a present Crank on Cylinder the EGT values?

thanks,

milos

Edited July 5, 2019 by brndiar

[kortopates]

Please try phrasing the question again. It’s not clear.


Sent from my iPhone using Tapatalk

[brndiar]

I apologize for my grammar, message was written from my phone with Editor ,  of course instead of Crank should be CRACK.

I do not have EDM, but In my last 50 hours I am not aware of overheating/schock cooling.  

For me where interesting to know how what are the symptoms of Cracked Cylinder.  What are EGT values on Cylinder with crack?

In My case i did not see any declining of compression reading,  (with cracks running between the intake and the exhaust valve seat),

but   EGT on Nr. 3 cylinder (with crack) where  always relative low. Could that by also sing of crack (a small one)?

thanks,milos

 

 

[brndiar]

 Foto of crack at my No 3 cylinder

[Guest]

15 hours ago, brndiar said:

 Foto of crack at my No 3 cylinder

This is only my guess based on years of maintenance experience.  The crack is at the base of the cooling fins on an exhaust port on an O-360 engine with parallel valves.  This is common on older cylinders which have higher operating hours.

You would not notice any loss in engine performance unless the crack entered the combustion chamber.

A replacement cylinder is required.

Clarence

[CaptRJM]

Without a way to measure EGT on each cylinder it is impossible to know which cylinder is at peak EGT first or last.  I have never operated a 0-360 but I think common practice is to run 50 degrees or more Rich of Peak

[brndiar]

[carusoam]

Without an engine monitor recording data.... the hints you are looking for require a flight engineer to be on the job...

Automation has caused so many job losses for engineers.... (have no fear, they found better jobs) 

Swap cylinder, get engine monitor...

Load data to Savvy...

link data here...

Then we can discuss what you are seeing....

How many hours are on that cylinder, how many times has it been oh’d?

What does a new one cost?

One of the things that cools the exhaust valve is oil through the guides...

Guides are cleaned using a procedure called the rope trick...

lots of info to catch up on...

The brief response you got from the doc.... he is one of MS’ key mechanics... (deep understatement) 

Check your logs see what you can find out about that and all other cylinders you have...

Have you seen pics of exhaust valves lately... there are a few around here....

Looking backward without any data probably won’t get you where you want to be... look forward to getting better data, cleaned, wobble free, valves with the best leak free dog house possible...

Then join the discussion on how to Best lean the O360 with that secondary fuel valve... called auto enrichment circuit... the 50year old OM or 40 year old POH doesn’t cover what modern operators want to know... 

PP thoughts only, not a mechanic...

Best regards,

-a-

PS feel free to edit the title of your post. As the OP, you can find the edit button....

[bradp]

Hey there,

Is that a first run cylinder or is it much older (ie since OH)? 

It’s doubtful that a crack would have any effect on EGT unless accompanied by a loss of compression.

Cylinder work at 17 years of service wouldn’t be the worst thing in my book.  I’d think of the cylinder as yet another accessory surrounding the important bits (cam and journal bearings, case).  You’ll get a good look at the insides with a cylinder pulled. 

A lot has been learned about engine management since your POH was published and your POH May include information that is flat outdated or incorrect. 

Make one of your first priorities an engine monitor.  You do not want to be running some cylinders LOP/some peak and some ROP unless your are at high altitude / low power settings .  The only way to know for sure where each cylinder is living is with an engine monitor. 

[brndiar]

Hi, thanks for your reply.

Engine was produced 1977 and overhauled  in 2002 (built in with 0 Hours  in 2002). I do not have any Info, If the cylinders have been exchanged (2002) or not.

It is true, that POH is 42 years old, but HAS NOT BEEN UPDATED from MOONEY SINCE THEN and THEREFORE STILL VALID.

Of course, there are new informations.

I have read a lot about laning and mixture setting. According to me the best Articles -please see below. 

My Mooney has Carb. LOP is not possible a and therefore I consider Monitor to be Uselessness. I try  follow Mike Busch´s leaning method.

P.S. EGT and CHT are in my Mooney attached ad Nr. 3 Cylinder (that one with Crack)

 

https://www.avweb.com/ownership/the-savvy-aviator-59-egt-cht-and-leaning/

https://www.avweb.com/features/pelicans-perch-16those-marvelous-props/

https://www.avweb.com/features/pelicans-perch-18mixture-magic/

 

milos

[Shadrach]

56 minutes ago, brndiar said:

It is true, that POH is 42 years old, but HAS NOT BEEN UPDATED from MOONEY SINCE THEN and THEREFORE STILL VALID.

Of course, there are new informations.

I have read a lot about laning and mixture setting. According to me the best Articles -please see below. 

My Mooney has Carb. LOP is not possible a and therefore I consider Monitor to be Uselessness.

The age of the POH is only relevant with regard to the factory’s policy on engine management at the time which is what the recommendations are based on.

Engine monitors are useful for much more than LOP. I could set almost any properly assembled and conforming IO360 LOP without an engine monitor and still be in at a very safe mixture setting. If you know what you’re doing you can use airspeed is a proxy for EGT.  

Lean to slight roughness

Wait for airspeed to stabilize

Enrichen slowly to max IAS

Lean for a ~5% reduction in IAS.

You think an engine monitor is useless for your application? Given you have to run run ROP,  how would you detect a minor intake leak?  If you reduce MP in the climb like a lot if O360 operators, what effect do you think that has on the volume of the leak and the mixture setting of the affected cylinder?

I know the answer but I’m asking for someone who thinks engine monitors are useless on carbureted aircraft...

 

[brndiar]

Hi.

With different power Producing by Cylinder with leak the motor would for sure not run smoothly any more. 

I am sure,  that "problem" would be detected without monitor too. Of course,  to determine exactly what the problem is the engine monitor great advantage. 

Anyhow,  I  think that without engine monitor I can operate my 1977 carb. Moony safely too.

M.

[Hank]

I do two simple things when setting power and leaning my 1970 carbureted C:

1. Set power as shown in my Owners Manual, now generally one of three settings, but conforming to MAPA's Key Numbers:

• Low level (<4000 msl):  23"/2300
• Mid level (4000-7000):  22"/2400
• High (>7500 msl):  WOT- /2500

  WOT- means to pull the throttle back until the MP needle wiggles a bit, so that the throttle plate is cocked inside the carburetor enough to create turbulence for improved atomization of fuel and better mixing with air. This will contribute to more even distribution and smoother running engine.

2. Lean via the EGT. Pull mixture until EGT peaks; just after peak, it will begin to run rough. Then push forward to your desired amount, and recheck it after a couple of minutes because it changes pretty slow.

Flying like this gives me almost 6 hours endurance on 52 gallons, at ~147 KTAS. No, I don't plan to fly that long, but have gone 4:45 twice with 11-12 gallons left (another 1:15).

While many (fuel injected) Mooney pilots decry the practice, I lean to 50°ROP. It worked well for thousands of pilots for decades before the introduction of engine monitors and worries about peak pressure inside the cylinders (no one has measured internal cylinder pressure; no one knows how much is too much; every power cycle has a peak pressure insude the cylinder). 

Good luck flying your Mooney. While the cracked cylinder is being replaced, examine your crankshaft for galling and wear. It will tell you about how the previous owners operated the engine. And let us know what you find!

[Shadrach]

7 hours ago, brndiar said:

Hi.

With different power Producing by Cylinder with leak the motor would for sure not run smoothly any more. 

I am sure,  that "problem" would be detected without monitor too. Of course,  to determine exactly what the problem is the engine monitor great advantage. 

Anyhow,  I  think that without engine monitor I can operate my 1977 carb. Moony safely too.

M.

A small leak would likely not cause the engine to run rough until the engine was leaned significantly but could cause it to run quite hot. You wouldn't know anyway if you were using roughness as the only leaning metric.  You might fly like that for quite a while until you ended up with a soft cylinder. 

[carusoam]

On 7/5/2019 at 11:44 AM, brndiar said:

Hi.

I  think that without engine monitor I can operate my 1977 carb. Moony safely too.

M.

Yes YOU can...

With an engine monitor, you can operate more safely...

Interested in word challenges, or answers to your engine challenge?

As far as flying using the original POH or owners manual... sure... that is legal... and required...

Would you not want to get the most updated collection of operations info for your plane?  It does exist in some cases... because Mooney printed it for your plane... but didn’t tell you how to get what applies to your plane...

See if your POH is printed with the Oct 1977 date on it...

 

Try and avoid statements regarding operating without an engine monitor... It clouds the discussion you are trying to have...

I flew an M20C for a decade without an engine monitor...

When the exhaust valve jammed open, I would have bought one on the spot... to know if I needed to land now, or circle back to the runway... circling back had crummy options for a crummy engine problem...

If I had an engine monitor, I would have known I had a power robbing valve in that cylinder... before I had the problem... if I had a fully loaded plane... I would be writing about not making it back to the airport...

It really sucks to have a misbehaving engine and not know how bad it is, or isn’t...

 

There will be a day that you will write something positive to the next guy... about your engine monitor... and how much you didn’t believe in their value... (prediction only... )

 

There are also people that have engine monitors, but aren’t familiar enough to get much use out of them...

So, I agree with you... YOU can fly safely without one.  

If your standard of safety is stuck in the 60s or 70s... there is plenty of room for improvement...

 

The real fun part of having an engine monitor... it can come with all kinds of recording possibilities, and display FF and fuel used... and calculate distance and fuel required to the airport... with alarms... (may require wiring to the Gps)

Since a known major accident cause for GA pilots, is running out fuel... having an engine monitor display really accurate fuel levels, combined with fuel used... it becomes really hard to run out of fuel...

So... now I raise a glass, and toast the new MSer.... Because, I firmly believe he can operate safely without an engine monitor, AND more safely with one! Cheers... 

 

What keeps you from wanting to have one or getting one?

Economics used to be a big challenge for some... things have changed pleasantly for this case...

Keeping the plane original is a quirky challenge for others... adding seat belts is a notable and acceptable update...

Not being an engineer or techy keeps some people from being interested in engine monitors... We have a solution for that as well... Somebody at Savvy can review your data with you or for you... but nothing beats being able... reading the data in flight for yourself...

PP thoughts only...

Best regards,

-a-