Cooling Issues - Solved!

[mccdeuce]

So I think I have solved my cooling issues.  #1 CHT probe was bad and has been.  Replaced the probe with upgrade to JPI 830.  Cylinder 1 now reading temp showed a steady split of 65-70 degrees between front and back.  

Talking with a local cooling whiz he suggested at looking at the bottom baffles or directing some airflow from the front to the back.  So I started digging and that lead to picture 1 where it appeared a piece of baffling was installed downward flat against another piece doing nothing.  Looking at the ol' Mooney Parts manual I was able to verify that part #3 was in fact installed upside down and directing the air in the right direction.  

Test flight hopefully tomorrow or the next day.  Really interested in seeing what this will do to temps on all cylinders.

 

 

[carusoam]

What is the strip of foam looking thing sitting/glued on the cooling fins on the copilot's front cylinder?

 

Best regards,

-a-

 

Edited March 8, 2017 by carusoam

[mccdeuce]

Bad picture?  Its my yellow screwdriver - makes sure I don't loose it...

[carusoam]

I see the yellow handle.  But it is a strip on the top of the cylinder in front of the screw driver...

Could be cylinder structure I'm not familiar with...

going forwards, what I see...

-screw driver

-fuel injector line

-first valve push Rod tube

- cooling fins

-spark plug

-second valve push Rod tube

- the front most cooling fins... with a strip on the top...?  (Wish I had a yellow marker)

Best regards,

-a-

Edited March 8, 2017 by carusoam

[RLCarter]

My E has them, I assume they help with resonance of the cooling fins

[mccdeuce]

19 minutes ago, carusoam said:

But it is a strip on the top of the cylinder in front of the screw driver...

Great talk on - and the answer is I have no idea what it is. Will look closer tomorrow.

[MB65E]

Correct RL, they are required. 

On your #1 cyl MC your temps should be warmer on 1 and cooler on the rest. I've used foil tape during engine brake-ins before to control temps and even them out. Sealing all the seams with Silicone is helpful too. 

On the 6cyl lycomings the prop Govoner blocks the ram air on the number 2 cylinder. On most new LYC overhauls number 1 runs cooler than the rest. Opposite on Continentals usually, 5 runs hot and is the first one to loose compression. (Due to the ALT blocking cooling). 

Funny the water cooled idea never caught on with aircraft. Air does funny things...

 

Let us know how your flight goes. -Matt

[Bob_Belville]

Turning that baffle over should really help. Good catch. I've been fussing with baffles and baffles seal for most of the 5 years I've had my E. Over all temps are now fine but front cyl are 35F cooler than rear.

[Shadrach]

I hope this solves your issue, but I have a hard time believing this was a mistake. I think there may be a good chance that the previous owner or A&P (wrongly) flipped the baffle piece in an effort to provide more airflow to that cylinder.   

[mooniac15u]

Some J owners have modified that baffle because the #1 cylinder runs hot.  Usually they trim it down an inch or so if I recall correctly.  I'm guessing a PO of your aircraft flipped that baffle because #1 was too hot.

[Jeev]

Interesting... After installing my overhauled engine I was having a hot #1.  My A&P ended up fabricating a baffle that is half the size of the original and my problem was solved. 

 

[Shadrach]

Just now, Jeev said:

Interesting... After installing my overhauled engine I was having a hot #1.  My A&P ended up fabricating a baffle that is half the size of the original and my problem was solved. 

 

Agreed. modifying or completely removing the baffle would be a better solution than flipping it.

[mccdeuce]

So I ran a short flight this afternoon to test and evaluate.  Climbed up to 5500 OAT was 8 deg.   Saw ALL cylinders come nicely into 320 - 340 degrees. 

I would like to think that this was done on purpose but I do not believe so.  I am going to reach back to previous owner but I have run sheet for GAMI calculations after the remanufactured engine was put in and it shows 330/370/405/385 for the temps.  

I think the bigger issue was a large hole in the back baffle and poor baffle seals (I have installed BeeGee's baffle kits) and saw the #1 down to 300 degrees.  More evaluation to be done, but for the most part I feel confident I can move on to other minor gripes now.

[THill182]

Very interesting. I am having a similar problem after a complete TOP overhaul. All went well, but on my IO550G (310hp conversion), now cylinders 3 and 4 (the middle one) run 20F hotter on CHT than the others. On climb-out, there is no way to keep them below 400F. Prior to the TOP no cylinder would go above 380 (by much anyway). Now, other cylinders don't either, but #3 and #4 will go that high, and remain 20F higher in cruise also (at/below 360F).

 

Any particular piece of the baffling from your picture above or mine below that might be responsible? Anything in particular to look at? (What part number?)

Edited March 9, 2017 by THill182
added baffling schematic

[N131MA]

I had a very hot #4 (was hard to keep below 390F) in cruise, and high CHT with all cylinders in my Eagle (310HP):

• I searched for gaps with a flashlight behind the baffling. I found cooling air leaks around the oil cooler, at the back of the baffling (28 in the drawing). Closed these gaps with high temp RTV: #4 issue fixed.
• The max fuel flow was set to low. Calibrated T/O fuel flow to 31gal/h: All CHT are below 380F at takeoff and during climb .

Hope it helps...

Peter

[THill182]

Definitely useful; that is my next step to go carefully through the baffling. Will look at that part carefully. Thanks!

[kortopates]

8 minutes ago, THill182 said:

Definitely useful; that is my next step to go carefully through the baffling. Will look at that part carefully. Thanks!

Since you had a recent top done, be sure the intra-cylinder baffles are all in place properly so that air is not lost without going through the cylinder fins. Also as Peter said above, make sure your take off full power fuel flow is up to spec. For the 310 HP, we (at Savvy) want to see 0.5 to 1.0 above TCM's spec or the Mooney STC  AFMS higher number which is 27.4 GPH - so we prefer 27.9 to 28.4 GPH to help with cooling.  

[mccdeuce]

10 hours ago, THill182 said:

Very interesting. I am having a similar problem after a complete TOP overhaul. All went well, but on my IO550G (310hp conversion), now cylinders 3 and 4 (the middle one) run 20F hotter on CHT than the others. On climb-out, there is no way to keep them below 400F. Prior to the TOP no cylinder would go above 380 (by much anyway). Now, other cylinders don't either, but #3 and #4 will go that high, and remain 20F higher in cruise also (at/below 360F).

 

Any particular piece of the baffling from your picture above or mine below that might be responsible? Anything in particular to look at? (What part number?)

 

Unfortunately I do not think my baffle is similar to yours to be able to help. Your part #6 is approx 4 different parts on my setup and it was one of those that was turned upside down.  The quality of the seals does make a huge difference though.  So if your seals don't look good it may be time for a swap.  Sorry can't really help.

 

On 3/8/2017 at 9:10 AM, Shadrach said:

I hope this solves your issue, but I have a hard time believing this was a mistake. I think there may be a good chance that the previous owner or A&P (wrongly) flipped the baffle piece in an effort to provide more airflow to that cylinder.   

I did check with previous owner and it was not done on purpose.  We all make mistakes, I'm just glad it is something simple.

[Shadrach]

10 hours ago, mccdeuce said:

Unfortunately I do not think my baffle is similar to yours to be able to help. Your part #6 is approx 4 different parts on my setup and it was one of those that was turned upside down.  The quality of the seals does make a huge difference though.  So if your seals don't look good it may be time for a swap.  Sorry can't really help.

 

I did check with previous owner and it was not done on purpose.  We all make mistakes, I'm just glad it is something simple.

To be clear, I see nothing wrong with tweaking the baffling to improve cooling.  I think that flipping the piece shown was a mistake.   While it increases exposed surface area above on the top side, I believe it did the opposite on the bottom.  If I were you, I'd try removing it all together first.  If that helps, I'd fabricate a new piece about 25% shorter than the original and keep trimming until you find whats best.

The baffle on your aircraft may have been perfectly place when it left the factory, but years of wear, maintenance, engine OH, etc... have likely had an effect on it's placement and  performance. 

I see baffles kind of the same way I look tying a knot, just because it's basically tied (assembled) in the proper way does not mean optimal performance. It needs to be "dressed" to ensure that the working parts of the rope are all bedded precisely in their proper place.  

[mccdeuce]

2 hours ago, Shadrach said:

 

To be clear, I see nothing wrong with tweaking the baffling to improve cooling.  I think that flipping the piece shown was a mistake.   While it increases exposed surface area above on the top side, I believe it did the opposite on the bottom.  

 

Agree - tweaking for better cooling should be done. By flipping this piece all it did was actually double the area on the bottom. I need to do another test flight but I'm pretty happy with it as is 340-350 on all cylinders. Think with some more gap sealing I should be able to drop 5-10 more degrees with rtv.

[THill182]

For the record: Tweaking the baffling every so slightly, filling in a few apparent holes in the baffling, seemed to have cured my Cyl #3/#4 elevated CHT's (IO550G, 310hp). Now all are in line with each other, and I can run at high power settings LOP even at high altitudes without going over 360F CHT on any cylinder. Climbout's are still a bit of a challenge now that the ambient temps have become summer like around here, but I can keep it all below 400F. Also, the cylinders have now 15 hours or less on them, so I expect temps to continue dropping....

[HRM]

On 3/7/2017 at 10:49 PM, carusoam said:

What is the strip of foam looking thing sitting/glued on the cooling fins on the copilot's front cylinder?

Those are fin stabilizers. They are used to reduce vibration.

[Guest]

The fin stabilizers are a mandatory change out at overhaul per SB240.

Clarence