High CHT temps and Baffle seal M20C

[jt_flyer]

Hi.  Just purchased a really nice M20C and I noticed I have about 1/2" gap between my baffle seal (attached to the aluminum baffling) and the front cowl at the bottom below the spinner.  This gap seal is obviously intended to fit into the slot in the cowl but it's way too short.  This gap goes the full width of the aluminum baffle. I'm experiencing high CHT temps but only in climb.  It's a apparent this material has not been changed in decades -if ever.  Can someone tell me the specs for this rubber seal and maybe a source for it?  Is it a kit or just roll stock?  Thanks. Joe 

PS just had the LASAR cowl enclosure installed but doesn't seem to have any cooling effect. 

[Guest]

You are correct, the lower baffle seal is meant to engage with the slot in the lower cowl.  Any good quality baffle sealing tape will work, along with large head pop rivets.

Clarence

[mccdeuce]

Talk to GeeBee on here. He manufactures precut seals of high quality. I replaced mine on my J and have been very happy. 

[Oscar Avalle]

Welcome to the world of the M20C... High CHTs have been following me for a long time... It seems to be a design issue. Some have a more serious problem than others, but overall, in particular in climb, M20C deliver high CHTs, in some cases even above what is recommended. I did everything to combat them (look up several discussions on this subject in Mooneyspace), and it helped to a certain degree. Now my CHTs are bearable... but one thing that had a real big impact was when I changed the technique on how I fly my M20C. Normally after rotating I pitched to Vy right away, that really seems to put a stress on our planes. My CHTs went up and they remained high for quite a while. I had a long back and forth with Paul from Savvyanalysis about the issue and he recommended to me that I should read an article about climb profile that he shared with me ( I am attaching for your reference the article). Basically what it says is if safe, then let the plane accelerate and then pitch up. I did it during my last flights and indeed the difference is remarkable. 

http://www.avweb.com/news/features/Climb-Faster-221694-1.html

Again, not a recommendation, but a point to think about.

Enjoy your M20C.

Oscar

[MooneyMitch]

On a side note to your post, based on my previous conversations with Paul Loewen from LASAR, creator of the cowl enclosure, the affect of the enclosure is strictly cosmetic only.

[RLCarter]

14 minutes ago, MooneyMitch said:

On a side note to your post, based on my previous conversations with Paul Loewen from LASAR, creator of the cowl enclosure, the affect of the enclosure is strictly cosmetic only.

I considered the LASAR cowl enclosure on my E, It does make it look better but I've heard both ways as far cooling & speed.

[MooneyMitch]

Not to alter the direction of this thread topic, but just to add my opinion of the cowl enclosure, it's my experience that installing the enclosure, for me, limits my access to the generator front mounting bolt/nut for ease of generator removal/installation.

Wiith the enclosure, it appears the lower cowl would have to be lowered for above mentioned access/actions.

This is based on my experience with a generator,  as opposed to an alternator modification installed.

However, I do like the looks of a clean looking LASAR cowl enclosure addition. 

[MooneyMitch]

Ok, time for me to get going, get off MS, and get ready for my Dodgers to whip the Cubs again today (I hope)!  

 

 

[Sabremech]

I'm biased, I like my cowl enclosure the best! 

 

[Hank]

Me, too, David. I'll like it even more when it's on my Mooney . . . . . 

 internal alarm to the solar disc rise. I will awaken you Dr. Gance so we can depart for a safer place." 
 
"Agh Sheila though I suggest you set your sensors to detect any movement of the military toward us." I told he

[HRM]

15 hours ago, Sabremech said:

I'm biased, I like my cowl enclosure the best! 

 

Could you post the side view? Thx!

[bonal]

To the OP you failed to mention what those temps were. Might be within what most are getting. But would definitely get the baffles back in their proper fit.

[DXB]

I've spent 2 years incrementally getting my baffles as tight as possible at some expense, while also excluding other causes of high temps. This effort has yielded real but  modest benefits, and I'm convinced that the root cause of the issue is that the cowl design with the doghouse is simply a  steaming pile of dogsh*t.  It's main weaknesses are drag and cooling the #2 cylinder.  I can't wait to hear the experience of the G owner who just got the Sabremech cowl.

[MooneyMitch]

21 hours ago, Sabremech said:

I'm biased, I like my cowl enclosure the best! 

 

Terrific!!!

[Sabremech]

1 hour ago, DXB said:

I've spent 2 years incrementally getting my baffles as tight as possible at some expense, while also excluding other causes of high temps. This effort has yielded real but  modest benefits, and I'm convinced that the root cause of the issue is that the cowl design with the doghouse is simply a  steaming pile of dogsh*t.  It's main weaknesses are drag and cooling the #2 cylinder.  I can't wait to hear the experience of the G owner who just got the Sabremech cowl.

Hi DXB,

The initial results of the recently completed G model in regards to CHT were not what I expected. They actually rose a little on #2 and #3. I've since learned that the Van's baffling I'm using is too tight to the back of the #3 cylinder and the front of the #2 cylinder which coincidentally is the side of the cylinder with the short fins. The fix is to add spacers and open the baffling up in these areas. I did this to mine and my customers airplane will be done tomorrow so we'll have results soon. 

Thanks,

David

[Sabremech]

5 hours ago, HRM said:

Could you post the side view? Thx!

Here's the best side views I have of the recently modded G model Mooney.

[pinerunner]

I was having trouble with higher CHT's in my M20E. Dropping the nose and climbing at something like 105 MPH helped a lot.  But first I get the gear up and the flaps (max extend speed 100 MPH) too. A slightly nose high AOA helps keep the speed under 100 until I'm cleaned up.

[llebhsoj]

Will the sabermech cowel ever be available to normal folks like me?

[Sabremech]

2 minutes ago, llebhsoj said:

Will the sabermech cowel ever be available to normal folks like me?

I don't know why it wouldn't be. I'm pricing it so it's relative to the value of our airplanes. It won't break your bank account like another cowling will.

Thanks,

David

[DXB]

Did the initial lack of CHT improvement on the G model got sorted out?  

[mike20papa]

The only reason to experience high CHT's in your 180hp Mooney is because of poorly maintained baffles.  I have a M20A that I have worked to maintain the baffles in "like new" condition and I never, ever see close to 400 in climb - no matter what the climb speed.  And I live in TEXAS.  The front baffle seal is silicone material you can order from any AC supply house - like AC Spruce.  Then, go down to NAPA and buy a tube of their silicone lube and keep it "liberally applied" so to keep it in good shape as it vibrates in the alumn. retaining groove. Yes, unless you think cyl. replacement is cheeper/easier than baffle replacement - go for it.  Also, check ALL the gaps around the starter, alternator, brackets, prop gov. oil line and seal with the thick wool material available from - AC Spruce.  pop rivets are required.  

Also, it's been documented that the cowling closure (which I have installed) improves cooling by preventing a reverse air flow in the lower cowling section.  

Then if you decide to turn that departing down wind into a chandelle - you can do that too.   Of course my A model is "light on it's wing".

[Shadrach]

On 10/3/2017 at 7:59 AM, mike20papa said:

The only reason to experience high CHT's in your 180hp Mooney is because of poorly maintained baffles. 

I would say that "one" of the reasons to experience high CHT's in a 180hp Mooney is because of poorly maintained baffles. It's certainly not the only reason.  Anecdotally speaking I have to say that I see far more in the way of elevated CHT complaints about the carburetted birds than their injected brethren.  I believe that many of the carburetted birds run too lean at max power.  The fact that they heat up so quickly tends to indicate a mixture issue to my way of thinking.  The fact that many are seeing CHTs near 400df or more on initial climb out suggests they are building heat rapidly during the takeoff run.  Even when a piece of baffle seal had detached, my F never saw anything like that. I would have to hang it on the prop on a hot day for quite a while to build the kind of heat that many of my carburetted friends are seeing during initial climb and long before reaching so much as pattern altitude.

Edited October 4, 2017 by Shadrach

[N601RX]

Another thing is the thermal capacity of the parallel valve cylinder vs the angle valve cylinder.  I had the charts for both a few years ago and think I posted them somewhere.

[carusoam]

Rare sighting...  Ross where have you been?

We were talking flame fronts the other day.  Probably electronic ignition or timing related...

My biggest challenge with my C's CHTs... as one of those ordinary guys, I only had one CHT.  Not the full set of four... Same with EGTs.

Best regards,

-a-

[Shadrach]

On 10/3/2017 at 4:08 PM, carusoam said:

Rare sighting...  Ross where have you been?

We were talking flame fronts the other day.  Probably electronic ignition or timing related...

My biggest challenge with my C's CHTs... as one of those ordinary guys, I only had one CHT.  Not the full set of four... Same with EGTs.

Best regards,

-a-

Anthony, 

I'm touched that you've noticed my absence! The answer to your question is that I have two kids under two, so my wife and I went to crazy town in June and will likely be staying for a while. I'll try to visit when I can!

Edited October 5, 2017 by Shadrach