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  #11  
Old 09-01-2019, 10:25 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 5,760
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Quote:
Originally Posted by scard View Post
There is something else going on there. More mass flow isn't what you're looking for here.
+1

especially since this is a new development for the OP. Best to look for what changed and resolve it. Cutting more opening will just create more drag. MANY planes like yours run under 400 in cruise without cutting the cowl, so best to look for other issues causing the overheating condition.

Larry
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  #12  
Old 09-01-2019, 10:50 AM
Mike S's Avatar
Mike S Mike S is offline
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,705
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Intake flange leak is one possible cause. Also intake tube coupler hoses and clamps can leak.

Pretty common problem.
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VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

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Sold after 240+ wonderful hours of flight.

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  #13  
Old 09-02-2019, 03:01 PM
ALagonia ALagonia is offline
 
Join Date: Jul 2017
Posts: 365
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Quote:
Originally Posted by rjcthree View Post
What are your other CHTs, oil temp, are you running
rich, at or lean of peak, carb or injection, what injection, ignition? Engine model? Thx.
Here is the data from two flights.
Sam James plenum
Carburetor
ROP

Flight #1
CHT's at cruise
-375 - 395 - 394 - 411
EGT's at cruise - 1261 - 1327 - 1267 - 1328
6000 feet 72% power 9.0 gph 71 degrees F
14.5 gph at take off power (full throttle)

Flight #2
CHT's at cruise
365 - 384 - 380 - 401
EGT's at cruise - 1259 - 1318 - 1263 - 1330
7,000 feet 70% power 9 gph 67 degrees F


Any thoughts about CHT on #4 cylinder?
Each of these flights lasted right at 2 hours. The numbers above did not change much. On the second flight the #4 CHT did eventually get down to the 390's.
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  #14  
Old 09-02-2019, 05:44 PM
oaklandaviator oaklandaviator is offline
 
Join Date: Dec 2014
Location: Somerville, Tn and Little Rock, Ar
Posts: 132
Default Oil cooler

Is the oil cooler mounted on the baffle behind the number four cylinder?
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  #15  
Old 09-02-2019, 05:50 PM
ALagonia ALagonia is offline
 
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Posts: 365
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Quote:
Originally Posted by oaklandaviator View Post
Is the oil cooler mounted on the baffle behind the number four cylinder?
Yes it is.
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  #16  
Old 09-02-2019, 06:13 PM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is offline
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 2,806
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#4 cylinder is leaner than the others. As you have a carburetor I would assume an air leak on the #4 inlet.

Carl
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  #17  
Old 09-03-2019, 01:04 AM
oaklandaviator oaklandaviator is offline
 
Join Date: Dec 2014
Location: Somerville, Tn and Little Rock, Ar
Posts: 132
Default Baffle

I would try making a curved aluminum piece to wrap over the number four cylinder and reduce the air lost over the oil cooler. By slowing the air down with a curved blocking plate, you'll increase the pressure available for cylinder cooling and also not adversely affect oil temps because the less air is slowed down and spends more time in the cooler.
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  #18  
Old 09-03-2019, 06:06 AM
jjbardell jjbardell is offline
 
Join Date: Jan 2017
Location: Phoenix, AZ
Posts: 227
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I added a small air dam in front of my #2 to balance the #2/4 cylinders. Not sure if it?ll help you much since your #2 is also a little warm.

https://photos.app.goo.gl/CVvbLtQsJKH1ruuN8

For my lower cowl mod, here are a few pics. This was very helpful And worth 10-20 degrees.

https://photos.app.goo.gl/jJnxB4WmZxrdQjoN6

https://photos.app.goo.gl/TAgmEaLKyiC5ZGv27
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Building - Zenith 750 [11323] CruzerDuty27.5
N67LJ RV9-A [90504] - SOLD
N83LJ Sonex [0864] - SOLD

https://rvpilotlife.wordpress.com/blog/home/
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  #19  
Old 09-03-2019, 07:11 AM
ALagonia ALagonia is offline
 
Join Date: Jul 2017
Posts: 365
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Quote:
Originally Posted by jjbardell View Post
I added a small air dam in front of my #2 to balance the #2/4 cylinders. Not sure if it?ll help you much since your #2 is also a little warm.

https://photos.app.goo.gl/CVvbLtQsJKH1ruuN8

For my lower cowl mod, here are a few pics. This was very helpful And worth 10-20 degrees.

https://photos.app.goo.gl/jJnxB4WmZxrdQjoN6

https://photos.app.goo.gl/TAgmEaLKyiC5ZGv27
Hard to make out your first two,pics. The last pic showing the exhaust was clearly understandable. I have a Sam James plenum. Any idea how your suggestions would help/affect my CHT?s with my plenum?
Thanks for posting
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  #20  
Old 09-03-2019, 07:33 AM
jjbardell jjbardell is offline
 
Join Date: Jan 2017
Location: Phoenix, AZ
Posts: 227
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Quote:
Originally Posted by ALagonia View Post
Hard to make out your first two,pics. The last pic showing the exhaust was clearly understandable. I have a Sam James plenum. Any idea how your suggestions would help/affect my CHT?s with my plenum?
Thanks for posting
The first pic is looking into the air intake at cylinder #2 (Lyc). The second is the side profile of the cowl cut back 45 degrees to open it up more.

Sorry, no experience with a Sam. They do look sexy though.
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Building - Zenith 750 [11323] CruzerDuty27.5
N67LJ RV9-A [90504] - SOLD
N83LJ Sonex [0864] - SOLD

https://rvpilotlife.wordpress.com/blog/home/
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