Rough Engine IO550 at COLD start only

[PT20J]

39 minutes ago, Healthpilot said:

Interesting. When you increase RPM in the video roughness seems to decrease. In my case it doesn't. If I increase RPM in the first 3 minutes roughness increrases. 

That's going to be dependent on the nature of the sticking. A valve beginning to stick may not stick every cycle, and it may be binding just enough that the spring closes it more slowly. That's why the EGT isn't closer to zero. So, the sticking can get better or worse with rpm. It's when it finally sticks hard that it can cause damage.

[Niko182]

SR22 guys never seem to have this issue. They firewall it on startup and it warms up really quick and smooth.

[Guest]

9 hours ago, Niko182 said:

SR22 guys never seem to have this issue. They firewall it on startup and it warms up really quick and smooth.

They’re not alone, a lot of Mooney guys don’t seem to understand idle speed either.

[Guest]

Sticking valve in a Continental is almost unheard of.  It also might be a bad valve lifter that isn’t pumping up.  Rope trick will allow the valves to be checked first.

[dzeleski]

12 hours ago, Healthpilot said:

Interesting. When you increase RPM in the video roughness seems to decrease. In my case it doesn't. If I increase RPM in the first 3 minutes roughness increrases. 

Im not increasing anything. The throttle is left completely alone. The drag on RPM is due to the #2 cylinder not firing and causing power loss.

[PT20J]

3 hours ago, M20Doc said:

Sticking valve in a Continental is almost unheard of.  It also might be a bad valve lifter that isn’t pumping up.  Rope trick will allow the valves to be checked first.

If it’s a lifter, can you hear the clatter at idle? 

[Guest]

1 hour ago, PT20J said:

If it’s a lifter, can you hear the clatter at idle? 

I would imagine if you were standing beside it with the cowls off you might hear it.

[Bolter]

On 2/14/2023 at 8:57 AM, Healthpilot said:

No plans to fly before checking. Annual is scheduled for week after next. This is the first time it happens. Does anyone know a good A&P in the Seattle area expert on Continental big bore engines that has access to a decent borescope? if not I will purchase one and give it to my mechanic. They seem to be quite cheap now. Is this one ok or not good enough?
5mm Ultra Fine Dual Lens Endoscope Camera, Hiacinto 5inch IPS 1080P Digital Inspection Camera with IP68 Waterproof, Automotive Scope Camera with 7 LED Lights, 16.5FT Semi-Rigid Cable, 32GB Card: Amazon.com: Industrial & Scientific

I am based on KPAE (also an Ovation) and have one of the Vividia scopes (not the latest version).  You are free to borrow it, as it spends most of its life on a shelf.  I do not think it will help for morning sickness, but just for your future reference.  PM me if you are interested.  

You asked about local A&P/IA options for your engine.  I took my 201 to Advanced in Troutdale and now my Ovation is there, right now.  They are the only shop I have used for  annuals and engine work since I moved to this area in 2019.  On a personal level, I do like Rachel's team at Crown/Regal.  But I have only gone there for basic things so far.  The big Continental is used in lots of other planes, so I would expect many shops can handle the engine work, regardless of Mooney experience.  

-dan

[Healthpilot]

21 hours ago, PT20J said:

That's going to be dependent on the nature of the sticking. A valve beginning to stick may not stick every cycle, and it may be binding just enough that the spring closes it more slowly. That's why the EGT isn't closer to zero. So, the sticking can get better or worse with rpm. It's when it finally sticks hard that it can cause damage.

If you look at the EGT data... How likely is it that both cylinders (1 and 3) have this same valve sticking issue? Not sure how to diagnose/ That's my problem.

[Guest]

32 minutes ago, Healthpilot said:

If you look at the EGT data... How likely is it that both cylinders (1 and 3) have this same valve sticking issue? Not sure how to diagnose/ That's my problem.

You have to do the rope trick on your cylinders.  This will allow you remove the valve keepers, rotators and springs, then check the valves for fit in the valve guides.  This should allow you to confirm valve sticking or not.

[Healthpilot]

46 minutes ago, M20Doc said:

You have to do the rope trick on your cylinders.  This will allow you remove the valve keepers, rotators and springs, then check the valves for fit in the valve guides.  This should allow you to confirm valve sticking or not.

This I get and can do I think. Thank you. 

[PT20J]

1 hour ago, Healthpilot said:

If you look at the EGT data... How likely is it that both cylinders (1 and 3) have this same valve sticking issue? Not sure how to diagnose/ That's my problem.

I don't know. It's pretty difficult to diagnose this from one snapshot. All that seems really clear is that cylinders 1 and 3 were not making much power for about 3 minutes after start. The signature does not look like an ignition problem since if both plugs weren't firing they wouldn't make any heat at all and if only one plug in each cylinder was firing it should run better with probably higher EGTs. That leaves air or fuel. Cylinders 1 and 3 are the rear cylinders on a Continental engine, so it might be good to look for anything common to them. Did you have the mixture full rich or leaned? I have seen cylinders cut out when leaned excessively and cold. It never hurts to do the simple stuff first: clean injectors and spark plugs, look for induction leaks (these  often screw up idle but don't much affect higher powers). If it's not anything simple, that leaves the valve train. It would seem strange for two valves to stick and it doesn't seem common on Continentals, but I did have a friend that had a stuck valve on an O-300 powered C-172, so it does happen.

Skip

[Healthpilot]

5 minutes ago, PT20J said:

I don't know. It's pretty difficult to diagnose this from one snapshot. All that seems really clear is that cylinders 1 and 3 were not making much power for about 3 minutes after start. The signature does not look like an ignition problem since if both plugs weren't firing they wouldn't make any heat at all and if only one plug in each cylinder was firing it should run better with probably higher EGTs. That leaves air of fuel. Cylinders 1 and 3 are the rear cylinders on a Continental engine, so it might be good to look for anything common to them. Did you have the mixture full rich or leaned? I have seen cylinders cut out when leaned excessively and cold. It never hurts to do the simple stuff first: clean injectors and spark plugs, look for induction leaks (these  often screw up idle but don't much affect higher powers). If it's not anything simple, that leaves the valve train. It would seem strange for two valves to stick and it doesn't seem common on Continentals, but I did have a friend that had a stuck valve on an O-300 powered C-172, so it does happen.

Skip

Thanks Skip. Will do. Good idea on sparkplugs and injectors. It seems a lot more likely to me. Mixture was full rich as per POH at cold start. 

[carusoam]

I’m Late to the party…. 

1) 40°F is hardly a cold start…

2) if cold enough… the engine just dies without running lo boost for a while…

3) two cylinders are not behaving like the other four… so definitely not a cold issue…. Cold would affect them all…

4) could be fuel injectors… a gami spread, even a quick one… would ferret out Something as bad as this…. 

5) once warned and operating… lean the engine until it turns off…. Do 1&3 quit first?

6) What does the run-up graph look like?

7) if you haven’t already… download the data… send to savvy, click share, copy link here…

 

8) Something quirky is going on…affecting only those two cylinders…

post the link…

Best regards,

-a-

[Pinecone]

29 minutes ago, carusoam said:

3) two cylinders are not behaving like the other four… so definitely not a cold issue…. Cold would affect them all…

Disagree.   Sticking valves are commonly only one cylinder and are related to cold.

Other things could be cold related, but only some of the cylinders.

[carusoam]

4 minutes ago, Pinecone said:

Disagree.   Sticking valves are commonly only one cylinder and are related to cold.

Other things could be cold related, but only some of the cylinders.

Thank you… Looks like I didn’t write something very clearly…. 

the issues encountered here are not normal behavior for a normal chilly engine…

+1 for cold affecting the probable sticky valves…

 

let’s also add…

9) a dental scope of the valves would be interesting…

Nice pizzas will indicate their structure is in good condition…

but, if they have heat marks… HAZs… that would be telling as well.  The rotators aren’t rotating…

 

10) +1 for the rope trick mentioned above…

the valve system seems pretty suspect from the data we have so far…

11) Valve failure is often found during high power operations… like T/O…

Soooo… don’t be in a rush to test fly without a good reason to do so…

 

PP thoughts only, not a mechanic…

Best regards,

-a-

[A64Pilot]

A compression test on a cold motor can often find a stuck valve too and is a very easy test, but Conti’s in my experience don’t often stick valves

[Healthpilot]

On 2/17/2023 at 4:01 PM, carusoam said:

I’m Late to the party…. 

1) 40°F is hardly a cold start…

2) if cold enough… the engine just dies without running lo boost for a while…

3) two cylinders are not behaving like the other four… so definitely not a cold issue…. Cold would affect them all…

4) could be fuel injectors… a gami spread, even a quick one… would ferret out Something as bad as this…. 

5) once warned and operating… lean the engine until it turns off…. Do 1&3 quit first?

6) What does the run-up graph look like?

7) if you haven’t already… download the data… send to savvy, click share, copy link here…

 

8) Something quirky is going on…affecting only those two cylinders…

post the link…

Best regards,

-a-

Here's the run-up graph of the same flight looks perfectly fine to me. 

Could have been a clogged fuel nozzle?

[carusoam]

Hp,

Great follow-up graph sharing!

Two things of notice…

1) The run-up is occurring soooo quickly… there is opportunity to get more value from the engine monitor…

2) look at the two peaks… they are supposed to be identical.  When they are different, it is time to check the ignition timing…

 

To get more value out of your run-up… allow the EGTs to peak before switching back to both, same with allowing them to come all the way back  down…

It may take 20 seconds or so in each switch position to allow the process to stabilize….

This allows us to know where the baseline is for calculating a really accurate rpm drop…  EGT peak vs baseline…

 

Graphically….   5&6 are running hotter than the others… during the run-up…

#6 didn’t wait for the run-up to separate itself from the rest.

 

if all the EGT sensors are factory located with a jig…  5&6 are showing a possibility of a blockage…

 

Running a Gami spread test can confirm how lean 5&6 are actually running… cylinder peak and associated fuel flow for each cylinder is really helpful to have…

But, looking at the OP… isn’t it 1&3 that we’re giving us the tough time?

 

How many hours are on the fuel injection system?

It looks like the fuel divider may be throwing some funk into the program…

 

 

This is where reviewing prior flights can be really helpful…

Do 1&3 behave this way consistently?

Do 5&6 behave this way consistently?

If you get a tight Gami spread…. This will give a better idea of what is working properly…

A really detailed run-up… will help ferret out ignition challenges…

Something funky is going on… but, it’s not real obvious to my untrained eye…

See if Savvy services fit in your budget… 

PP thoughts only, not a mechanic…

Best regards,

-a-

 

 

[Healthpilot]

13 minutes ago, carusoam said:

Hp,

Great follow-up graph sharing!

Two things of notice…

1) The run-up is occurring soooo quickly… there is opportunity to get more value from the engine monitor…

2) look at the two peaks… they are supposed to be identical.  When they are different, it is time to check the timing…

 

To get more value out of your run-up… allow the EGTs to peak before switching back to both, same with allowing them to come all the way back  down…

It may take 20 seconds or so in each switch position to allow the process to stabilize….

This allows us to know where the baseline is for calculating a really accurate rpm drop…

 

Graphically….   5&6 are running hotter than the others… during the run-up…

#6 didn’t wait for the run-up to separate itself from the rest.

 

if all the EGT sensors are factory located with a jig…  5&6 are showing a possibility of a blockage…

 

Running a Gami spread test can confirm how lean 5&6 are actually running… cylinder peak and associated fuel flow for each cylinder is really helpful to have…

But, looking at the OP… isn’t it 1&3 that we’re giving us the tough time?

 

How many hours are on the fuel injection system?

It looks like the fuel divider may be throwing some funk into the program…

 

 

This is where reviewing prior flights can be really helpful…

Do 1&3 behave this way consistently?

Do 5&6 behave this way consistently?

If you get a tight Gami spread…. This will give a better idea of what is working properly…

A really detailed run-up… will help ferret out ignition challenges…

Something funky is going on… but, it’s not real obvious to my untrained eye…

See if Savvy services fit in your budget… 

PP thoughts only, not a mechanic…

Best regards,

-a-

 

 

 

Will do Carusoam thank you for your input and suggestions.
This issue at startup only happened once so far.

The answer to your question is no. There is really no exact consistency during run-up: i.e. sometime C4 runs warmer than others.

But in general C1 and C3 tend to run 20 to 30 degrees cooler when I look at most previous flights as well. That's true during cruise flight as well. 

Will do what you recommend and hopefully report back what I learn.

 

[Healthpilot]

On 2/19/2023 at 3:35 PM, Healthpilot said:

 

Will do Carusoam thank you for your input and suggestions.
This issue at startup only happened once so far.

The answer to your question is no. There is really no exact consistency during run-up: i.e. sometime C4 runs warmer than others.

But in general C1 and C3 tend to run 20 to 30 degrees cooler when I look at most previous flights as well. That's true during cruise flight as well. 

Will do what you recommend and hopefully report back what I learn.

 

Ok reporting back after annual inspection. As expected the culprit were the two bottom sparkplugs. Engine starting smooth and temp rising evenly now. 

[Ragsf15e]

3 hours ago, Healthpilot said:

Ok reporting back after annual inspection. As expected the culprit were the two bottom sparkplugs. Engine starting smooth and temp rising evenly now. 

Glad you didn’t go yanking cylinders!