Rate my baffle seals

[Shadrach]

On 7/20/2023 at 12:24 PM, redbaron1982 said:

I'm going to give this a try, first is in the IPC, so it is supposed to be there. Second, it's cheap (McFarlane has this for 20usd I think). Third, the issue I'm having is with Cyl #3, and my flow dynamics master (just kidding) tells me that this part missing allows air to escape to the lower side through the front of Cyl #1, preventing this air from reaching Cyl #3. Cyl #1 and #3 are consistently 20F hotter than 2 and 4 in my case.

If it makes things worse, I can always take it out.

#3 is almost always the hottest CHT and coincidentally the leanest (first to peak) on IO360 powered Mooneys. I do not see how omitting the front baffle on #1 would be beneficial. The additional flow around the front of #1 may lower the #1 CHT, but it may create a localized increase in pressure in the lower cowl stemming the flow of cooling air around the back of #1/#3 as wall as the front of #3. Some cowling tweaks help and some make things worse. Probably best to restore to stock and then reevaluate.

  Also, there is a concave pocket in the baffle seal wall behind #3, make sure it is aligned in such a way as to allow flow around the back of #3. If that pocket is not lined up properly, almost know air will flow around the back side of #3. See image below. This is an image I captured looking straight down at the top of #3 and #1 in the dark with a shop light in the lower cowl. Notice no light behind #3?  The Cylinder fins are offset from the barrel so that they do not provide flow around the back side of the cylinder. Note the back side of cylinder #1, all the light is coming through the fins of #3.  This si why is is essential that the pathway behind #3 be aligned and unobstructed.

I agree with Rich on the RTV. The RTV on your front baffle seals may be causing turbulence that is detrimental to airflow. It's a poor aesthetic that in all likelihood has no benefit.  The front baffle seals on my F model have been in service for 3300hrs over the last 55 years. The engine runs consistently on the cool side for conditions (have trouble keeping #1 and #4 >300° in winter). They have never been "glued" to the cylinders. 

 

[redbaron1982]

7 hours ago, Shadrach said:

#3 is almost always the hottest CHT and coincidentally the leanest (first to peak) on IO360 powered Mooneys. I do not see how omitting the front baffle on #1 would be beneficial.

After adding the missing baffle, the Cyl #1 is now the hottest, being at 420F during climb. Without the baffle, the hottest is #3 at 410F. That's why I'm thinking of removing the baffle that I've just added.

[Shadrach]

44 minutes ago, redbaron1982 said:

After adding the missing baffle, the Cyl #1 is now the hottest, being at 420F during climb. Without the baffle, the hottest is #3 at 410F. That's why I'm thinking of removing the baffle that I've just added.

I would not be happy with those numbers. Not because I think it”s   frying cylinders but because I know it can run cooler.