Cylinder Temperature Issue

[EricJ]

I bet you just found the problem.   Find the proper retainers and fit that the way its' supposed to be.   The IPC should show the proper pieces and attachments.  The temp spike may be because that piece moved during the flight.

 

 

[Brandontwalker]

3 hours ago, EricJ said:

I bet you just found the problem.   Find the proper retainers and fit that the way its' supposed to be.   The IPC should show the proper pieces and attachments.  The temp spike may be because that piece moved during the flight.

 

 

According to the IPC, a $57 spring should go here. I could see how a spring may keep the rear baffle from closing when the pressure forces the front baffle open more. Still struggling with the temperature spike though. 

[EricJ]

13 minutes ago, Brandontwalker said:

According to the IPC, a $57 spring should go here. I could see how a spring may keep the rear baffle from closing when the pressure forces the front baffle open more. Still struggling with the temperature spike though. 

There are two per side.   It looked like you were missing both on that side.

[bfreelove]

That’s definitely the problem. If that’s loose, the lower opening for 3 becomes too large, not keeping the air in contact with the the fins, also number one becomes too large allowing too much air to pass through there (taking some flow from number 3).  You can see by the large amount of lower baffle wrap on cylinder one that there is a lot more pressure available for that location and the design is an attempt to throttle the flow for that cylinder.  If the baffles are miss adjusted there it will cause a large imbalance.

I also notice the inner lower baffle tie spring is also missing. 

[bfreelove]

On the Saavy data I only see CHT and EGT. Was there any change in flight profile that corresponded with the temp spike? Change in MAP or RPM?  

[Guest]

From the IPC:

 

[Brandontwalker]

7 minutes ago, bfreelove said:

On the Saavy data I only see CHT and EGT. Was there any change in flight profile that corresponded with the temp spike? Change in MAP or RPM?  

Negative. Throttle, mixture, and prop were constant during the spike. 

[bfreelove]

In that case the spike is either from the lower  baffle suddenly shifting (it’s definitely not stable right now, both sides need to be held really tight) or the probe is going bad (I know you swapped to check but could be two issues at once). I can’t think of any internal issue with the cylinder that would cause a sudden increase in CHT without a corresponding change in EGT. 

[carusoam]

+1 on proper parts installed the proper way...

Trying to get reproducible results without standard parts is going to be near impossible....

Egts are all close... CHTs are all close except the one...

Make sure it isn’t a different type of TC mounted in something other than a TC well... 

PP thoughts only, not a mechanic...

Best regards,

-a-

[Brandontwalker]

This weekend was full of more troubleshooting failures. All loose baffling was secured with owner produced parts (safety wire and springs) to see if the issue would be altered. Temps were initially hovering around 400, but I was not surprised as the ambient temperature was in the 80’s and I was running it hard at low altitude. However, a new problem manifested in cylinder 3 in the form of sharply declining egt. CHT reduced with the decline in EGT. The latest log is posted below. I’m done. It is getting checked in to the engine shop tomorrow. I appreciate all of your help. In the event I don’t shoot it like a lame horse, I will post the findings. 
 

https://apps.savvyaviation.com/flights/3944915/5a6ed33f-a851-4cad-8a1d-850460430ace

[carusoam]

Yikes..!

You are definitely onto something there...

I updated the graph with blue arrows pointing out a couple of EGT anomalies, and a matching big CHT anomaly in the JPI graphs...

looks like cyl #3 may be calling... and asking for attention...

Looks like something is possibly blocking fuel flow to that cylinder... then not.... and then again....

Got any Gami spread data to go with that?

Gami spread data may indicate that the FF has been blocked a fair amount in that cylinder...

Typical blocked fuel injectors usually get blocked and stay blocked.....

With the CHT running away, from the moment the engine is started... there might be something serious going on inside that one cylinder... or inside what is feeding that cylinder...

This may be further upstream... in the fuel injector system...

Got any pics of the valves?

Looks like something is going on with the mixture for that one cylinder...

• It starts out lean and heats the CHT higher than the others....
• Then at two points... getting too lean to burn...(?) 
• no flame, things cool inside that cylinder.... including the cylinder itself...
• Looks like you pressed the mixture knob in and the flames returned...

Focus on the EGTs first, CHTs come after keeping the engine running... 

Are you seeing what I am seeing?

Can you share more flights of data?

Are you familiar with the babyfood jar test for fuel injectors?

PP thoughts only, not a mechanic.

Best regards,

-a-

 

[bfreelove]

Hmmm.  That's a bit of a head scratcher.  I was really hoping it was just the baffles.  Was there any engine roughness with the drop in EGT? 

[carusoam]

Bfree,   Let’s jump ahead a few posts...

How bad was the vibration when the Cyl#3 went on hiatus?

-a-

[Brandontwalker]

28 minutes ago, bfreelove said:

Hmmm.  That's a bit of a head scratcher.  I was really hoping it was just the baffles.  Was there any engine roughness with the drop in EGT? 

No roughness whatsoever. 

[bfreelove]

Interesting, maybe first signs of a valve issue?, but seems strange that there's no roughness given the amount of change in EGT.   Good luck with the engine shop, I hope it's something easy and inexpensive.  Either way good job catching it before it was a safety issue!  

[ArtVandelay]

TL;DR...did you borescope the cylinder(s)?
I’d also increase the sampling rate to 2 seconds, can help with more transient issues.

[Brandontwalker]

So my Mooney was dropped off at the engine shop on Friday. Although compressions were 80/80, we pulled the cylinder and immediately discovered one of the compression rings was shattered and there was a spiral gouge on the cylinder wall. Long post short, cylinder 3 is getting replaced with a factory new assembly from Lycoming. Obviously not the cheapest outcome, but at least it will be fixed and reliable again. I truly appreciate everyone’s input as I am sure you saved me a small mint in troubleshooting costs.




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[carusoam]

Great follow up, Brandon!

Including pics is awesome!

Best regards,

-a-

[RoundTwo]

On 5/16/2020 at 7:26 PM, M20Doc said:

From the IPC:

 

Does anyone know where I can get the coil Spring for 

BAFFLE RETAINER SPRING - 600372-501

Lasar is out but I can twist up the wire holder if I can find a spring.