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  #1  
Old 11-28-2011, 06:58 AM
rwayne rwayne is offline
 
Join Date: Jan 2005
Posts: 114
Default Louvers and CHT

Like so many others I am having problems with high CHTs. My engine is broken in and I've confirmed minimal baffling leakage. Interestingly oil temps are doing fine (185 to 205F). I've read of others using louvers with great success but have not heard much about them lately. Anyone with a similar problem find them helpful; or another idea? Thanks.
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  #2  
Old 11-28-2011, 08:14 AM
ReidVaitor ReidVaitor is offline
 
Join Date: Jun 2006
Location: SoCal
Posts: 174
Default high CHT

What power setting and what altitude? I had 400f plus on my 1,2,5 and 6 cylinders. But this is at 75% or more.
I cut the front plates from cylinder 1 and 2 about .30 or so and that brought my temps down 10F.
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  #3  
Old 11-28-2011, 11:56 AM
rwayne rwayne is offline
 
Join Date: Jan 2005
Posts: 114
Default Temps

I'm getting above 400 until I hit cruise and power back to 23.5" and 2450rpm, then get 390 or so. I usually climb at 26" and 2500rpm but often back off as CHTs climb. By "front plates" do you mean the metal baffle at the bottom of the air intakes? Thanks for the help.
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  #4  
Old 11-28-2011, 01:55 PM
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MauiLvrs MauiLvrs is offline
 
Join Date: Jan 2008
Location: KTCY
Posts: 643
Default

Quote:
Originally Posted by rwayne View Post
. Anyone with a similar problem find them helpful; or another idea? Thanks.
We opened the cowl exit 5/8 inch.
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  #5  
Old 11-28-2011, 04:28 PM
Moura Moura is offline
 
Join Date: Oct 2009
Location: Uberaba, MG, Brazil
Posts: 122
Default

Ever tried LOP. I am never over 350 running LOP 65% or less.
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  #6  
Old 11-28-2011, 05:42 PM
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MauleDriver MauleDriver is offline
 
Join Date: Aug 2006
Location: Lake Ridge Aero Park - Durham NC
Posts: 199
Default I'm topping out at 380F - WOT during initial climb out

That's 380F on Cyl 2 which is now my hot cylinder.

I first sealed up everything I could with hi temp silicone. The baffle holes for the engine mount bolts are sealed with cups (big gaps there).

Then, noticing that Cylinder 1 and 2 were my hot cylinders, I cut down the dams at the air intakes. An improvement was noted but #1 was still hottest so I removed the entire dam. Now #2 is the hottest so I'm going to completely remove that dam as well (as others have suggested). If everything else stays the same, I'll be running 365 to 376 during the climb. It may be hotter in summer - these temps were seen on a 55F day.

I wish my oil access door didn't leak so much cooling air.

Bill "at the tuning everything up stage" Watson

Quote:
Originally Posted by rwayne View Post
I'm getting above 400 until I hit cruise and power back to 23.5" and 2450rpm, then get 390 or so. I usually climb at 26" and 2500rpm but often back off as CHTs climb. By "front plates" do you mean the metal baffle at the bottom of the air intakes? Thanks for the help.
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  #7  
Old 11-28-2011, 07:25 PM
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RV10inOz RV10inOz is offline
 
Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,271
Default

I removed the dams as well, we regulary get 300F in winter to 335 in summer with all temps within 17F spread.

Climbs are never above 380 and usually 365 +/- the spread of the day.

We have the 5 slot I think louvres on the underside of the cowl.
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  #8  
Old 11-29-2011, 01:32 PM
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Space Cadet Space Cadet is offline
 
Join Date: Mar 2007
Location: Denver, CO
Posts: 211
Default Seal

Quote:
Originally Posted by MauleDriver View Post
I wish my oil access door didn't leak so much cooling air.
Bill- you tried putting a gasket seal on that door? You can just put a bead of RTV or similar on one side, clear tape on the matching flange, close it and let it dry. Should seal it right up. Course, I haven't done it to mine yet, on the list of finishing items...

Dwight
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  #9  
Old 11-29-2011, 03:43 PM
AaronG AaronG is offline
 
Join Date: Sep 2009
Location: Hartford, CT
Posts: 97
Default

My temps started really high during flight test (400+) in cruise. I did the following in order of effectiveness.

1. Installed wheel pants and fairings
2. Cut down the blocker plates in front of cylinders 1 and 2
3. Added a fiberglass baffle to the top cover that provides a close fit around the prop governor
4. Sealed every little baffle leak i could find with rtv

After all of this, my hottest runs around 360 in cruise on an 80 degree day. Climbs on this same day are around 400 at Vy but i like to climb out at 125 knots where temps stay around 180. When i go lean of peak the 360 cruise temp on the hottest drops to around 320, with the coldest around 295.

My next step would have been to add baffles, but with the temps above, i didn't see the need.

Aaron
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  #10  
Old 11-29-2011, 06:08 PM
Strasnuts Strasnuts is offline
 
Join Date: Jan 2009
Location: Salt Lake City, Utah
Posts: 554
Default Hottest Cylinder

My #5 is my hottest cylinder. I cut my front plates down by half before I started and now I want them back. My engine ran high for the first 10 hours then came down substantially.
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