High CHT on one cylinder - O-360-A4M

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Moonshine
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High CHT on one cylinder - O-360-A4M

Post by Moonshine »

Noticed something interesting on my engine data - #1 jug is positively running hot. More evident at higher power settings.
Now, I understand that my -A4M is somewhat different that -M1A's most of you guys have, but would appreciate any suggestions
Here's a good sample of what I'm seeing:
http://www.diamondaviators.net/reports/flights/1800

My ideas so far:

- check the temp rating of the spark plugs, replace them all. I believe Lance said that his airplane originating from the same operator and maintenance facility had a wide array of different plugs.

- check baffling. Didn't see anything weird there, and the fact that #3 is doing fine and #1 is acting up tells me that the chances of this being a baffling issue are pretty slim.

- check for exhaust stack integrity. Seemed fine, but we'll take another look.

- check the CHT probe to make sure it's the same thing as on the other cylinders.. Vaguely remember seeing "replaced CHT probe with serviceable" in the logs.
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Lance Murray
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Re: DA40 HID Lights from Lo Presti ...

Post by Lance Murray »

Here is a good list of things to check.

http://www.sacskyranch.com/eng23.htm
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Re: DA40 HID Lights from Lo Presti ...

Post by Moonshine »

Thanks, Lance! Was reading that some 10 mins ago - but looks like we are in the wrong thread :)
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Re: High CHT on one cylinder - O-360-A4M

Post by Moonshine »

Fascinating stuff

Took the plane to mx, checked the plugs (all good), switched the upper and lower on #1 (didn't do much in the overall EGT picture)...... removed a piece of bubling "fireproofing" paint on the upper cowling that was sitting right on top of the #1.
Runup before
http://www.diamondaviators.net/reports/flights/1803
Runup after
http://www.diamondaviators.net/reports/flights/1804

Need to go fly and see if it did change something - runup temps look better. Go figure.
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Re: High CHT on one cylinder - O-360-A4M

Post by Moonshine »

Went flying for a bit today - CHT #1 where it should be.
Took note of some interesting numbers for 40FP - lazy takeoff at 2300lbs - 80' msl, 30.10" baro, +33C and no wind - 2050 feet from start of the roll to positive rate of climb.
Went to do some takeoffs and landings at wet grass strip (fairly tall grass, definitely over 10cm in the book) - 35 Msl, rest the same, managed 1780'.
Came back, quick rest, wanted to go flying again - dead spark plug on #3.
Off to get the M2508 and 3/4" tempest fine wires...

http://www.diamondaviators.net/reports/flights/1809
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Lance Murray
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Re: High CHT on one cylinder - O-360-A4M

Post by Lance Murray »

You will like the Fine Wires. I am not sure why the other plugs load up so easily.
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Re: High CHT on one cylinder - O-360-A4M

Post by BlackMammoth »

Fine wires rock!
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Rick
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Re: High CHT on one cylinder - O-360-A4M

Post by Rick »

BlackMammoth wrote:Fine wires rock!
Indeed! I went from having fouling issues every other flight (despite aggressive leaning both ground and air) to not a single problem since installing the fine wires. I swear it runs smoother, too! :thumbsup:
Roanoke, VA (KROA)
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Re: High CHT on one cylinder - O-360-A4M

Post by Moonshine »

Affirmative - fine wires run smoother and allow for peak ops on my O-360 :)
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