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  #1  
Old 02-19-2020, 02:24 PM
findane findane is offline
 
Join Date: Oct 2014
Location: Naples, FL
Posts: 51
Default too cool cylinders and oil temps

I have a James cowl over a James Plenum with a Superior IO320, a 9:1 compression running a 3 blade Catto prop. I've got 9 hours on the engine. The plenum seems to work too efficiently. Cylinders 1 and 3 run very cool, about 200 degrees for 1 and about 250 for 3. The James Plenum on the right side directs the incoming air directly into 1 and 3. On the left side 2 and 4 run at normal temps of between 325 and 350 as the incoming air is partially blocked and directed over the cylinders

Have any other James plenum owners experienced the same problem? Do I need to add some baffling in the right intake to cut down some of the incoming air. In addition, I remotely located a 13 row oil cooler behind and below the #4 cylinder. It's working too efficiently as my oil temps won't rise above 160 degrees. What's the best solution for raising the oil temp?
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  #2  
Old 02-19-2020, 02:36 PM
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jrtens jrtens is offline
 
Join Date: Apr 2018
Location: Sandy, Utah
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Default

I use varying amounts (depending on the air temp) of hi temp foil tape on the oil cooler to get the oil temp I want. This works on mine because it is a constant flow (no thermostat) - not sure what you have.

https://smile.amazon.com/gp/product/...91CK8ZYM&psc=1
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Last edited by jrtens : 02-19-2020 at 03:53 PM.
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  #3  
Old 02-19-2020, 03:15 PM
lr172 lr172 is offline
 
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Location: Schaumburg, IL
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I know little about the james cowl/plenum, but I struggle to believe a spread of 200 to 350 degrees across cylinders on the same well running engine, regardless of where the air is flowing. Might want to check the CHT sensor accuracy as well as other things that could be causing low CHTs. I might believe the 250 number, but quite suspicious on that one as well. Simple tape to block airflow, as mentioned above, will help to confirm that.

I just can't fathom an engine running greater than 65% power in florida weather to have a CHT of 200 without some type of problem.

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Last edited by lr172 : 02-19-2020 at 03:21 PM.
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  #4  
Old 02-19-2020, 05:54 PM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
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I did not have that much temperature difference on my James cowl. IO360 M1B std Cr, Mags. Standard small Niagara cooler.

Not that it is affecting your engine but consider that inlet air for cooling either goes through their cooler or over the engine and you sort through this issue.

The large temperature delta would be the first thing to check. A good place to start is the CHT probes, to ensure they are correctly wired and yielding an accurate temperature.

I found the baffles (tape typically) on the front of the heads can change the front rear temps some but not for side to side.

IMO, if the plenum leakage around the baffles (not going through the fins) is low, the primary control of temps is the open exit area under the heads and barrels.

Leakage by the intersection baffles under the cylinders on mine was huge. Use the tried and true light method to check and repair.
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  #5  
Old 02-20-2020, 01:40 AM
PCHunt PCHunt is offline
 
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Location: San Diego, CA
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I think I'd be swapping sensors, and checking wiring, as mentioned by previous posters, before I modified the baffles. Swap sensors side to side, see if the problem "moves" with the sensors.
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Last edited by PCHunt : 02-20-2020 at 01:45 AM. Reason: Added comment.
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  #6  
Old 02-21-2020, 03:04 PM
findane findane is offline
 
Join Date: Oct 2014
Location: Naples, FL
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The gentlemen who purchased James cowl responded very quickly. They echoed the same. Check the CHT probes and wiring. I plan to swap 1-3 with 2-4.
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  #7  
Old 02-21-2020, 03:37 PM
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Zuldarin Zuldarin is offline
 
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Location: Snoqualmie, wa
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Somebody much more electrical knowledge can confirm (or debunk) but I've been told that the type of wire has to match the type of probe. If somebody uses the wrong type of wire then the sensors will not report the proper values.
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  #8  
Old 02-22-2020, 10:46 AM
climberrn climberrn is offline
 
Join Date: Oct 2008
Location: Carson City, NV
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Omega.com

They have many articles and specifications on thermocouples. Have changed some of my problem connections over to their plugs. Lots of resources on that site.

Yes, the wire needs to match the type of probe. They have different connectors for the J and K probes. I canít tell you whatís different but they have different ones listed for the different probe types. You can do the boiling water test on the probes to see if they read a known temperature.
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  #9  
Old 02-22-2020, 11:32 AM
lr172 lr172 is offline
 
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J and K type wires have different colors, so easy to identify. Seems unlikely that an engine has two CHTs with correct wire and two with incorrect wire. Far more likely to be a bad thermocouple or improper installation.
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  #10  
Old 02-22-2020, 01:18 PM
Jpm757 Jpm757 is offline
 
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Just curious, if you power up the airplane cold, all of your EGT, CHT and oil temp should read the same.
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