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Jim Mantyla
 Post subject: Engine Too Cold
PostPosted: Fri May 25, 2018 10:30 am 
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Location: Barrie, Ontario,Canada
Guys,

I am wondering if my engine is running too cold. Let me explain. When i bought the plane the CHT was about 360F at cruise with the outside temperature about 75F. I did some changes to the baffling and the CHT came down to about 320-325F with outside temps about 75F. This winter I sealed all the holes I could find and changed the baffle tape material to really seal everything up so all the incoming air has to go through the cooling fins.

When I did my first flight this year with the outside temp about 40F the CHT was 260-265F. Last night I was out and the outside temp was 77 F and the CHT got as high as 302F in cruise and 320F on climb out. I believe my CHT is working because it indicates the correct ambient temp before I start up.

Your thoughts on this would be appreciated. Maybe I need to poke some holes in the baffles so that they are not as efficient, or maybe cut down the air inlet area? I have a Ratray cowl.

Regards,

Jim


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jrevens
 Post subject: Re: Engine Too Cold
PostPosted: Fri May 25, 2018 12:27 pm 
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I think your CHTs are great, Jim. IMHO, cooler is always better - within reason of course. It’s not directly like oil temperature, where you want to reach a temperature sufficient to remove water.

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Arvada, Colorado

T-18 N71JE (sold)
Kitfox 7 SS N27JE


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Rich Brazell
 Post subject: Re: Engine Too Cold
PostPosted: Fri May 25, 2018 1:36 pm 
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Location: Jamul, CA (San Diego area)
For my 0-360 Mama temp. (lycoming manual) sez...

CHT

400 deg. or below . :P
500 deg. max . :o
150-400 for max service life at cont. operation . ;)

RB O0


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Jim Mantyla
 Post subject: Re: Engine Too Cold
PostPosted: Fri May 25, 2018 1:39 pm 
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Location: Barrie, Ontario,Canada
I should have mentioned I have an IO-320 in my plane.

Jim


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jrevens
 Post subject: Re: Engine Too Cold
PostPosted: Fri May 25, 2018 6:07 pm 
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Jim Mantyla wrote:
I should have mentioned I have an IO-320 in my plane.

Jim



Shouldn’t matter.

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John Evens
Arvada, Colorado

T-18 N71JE (sold)
Kitfox 7 SS N27JE


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TonyNZ
 Post subject: Re: Engine Too Cold
PostPosted: Fri May 25, 2018 6:18 pm 
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Like John says, if cyl temps are mid range no problems. Just make sure oil temp is 80 C plus to keep moisture out.
Tony S
ZK-VMS


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Unclerap
 Post subject: Re: Engine Too Cold
PostPosted: Fri May 25, 2018 9:08 pm 
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Single probe or 4? Peak EGT at cruise? Most 4 cyl lycs run best lean and in the 300-350 CHT range as previously stated.


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Jeff J
 Post subject: Re: Engine Too Cold
PostPosted: Sat May 26, 2018 8:21 am 
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Your temps sound okay but there is quite a spread between 77 degrees and 325 degrees. It is posiible the probe could be good at low end and way off high. If you are serious about checking it then I suggest the probe be suspended in boiling water (212 degrees) or some other medium where you can measure the temp to check it. I ran into an oil temp probe on a PT6A a while back that was good at ambient but 20 degrees off at 212. If the error scale was constant then it could have been off by 40 at 325.

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Doug S
 Post subject: Re: Engine Too Cold
PostPosted: Sat May 26, 2018 9:09 am 
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Location: Daytona Bch, FL
If the temps. are correct, you can add more performance (speed or economy) start shrinking outlets of cowl.
I would think you could bring CHTs up into the 325 range with little worry & a few more knots (or MPG)


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