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What are your CHT's After LASAR Cowl Installation


C.J.

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On 10/3/2022 at 3:16 PM, MooneyP87 said:

Also getting 420-430F right after takeoff on initial climb out, especially when it's hot out. Cruise is around 360-380F depending on power %. Like everyone stated previously, I think you do need to have it checked for the idle/taxi temps as those seem abnormally high, even for a C.

CHT probe being checked for accuracy on Monday. Hopefully that's the issue.

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On 10/2/2022 at 2:09 PM, DXB said:

I'm pretty sure they all have a doghouse, which is a piece of dogsh*t in my view.  Crap mixture distribution via the carb is another offender, and perhaps the dominant one  - It's really just #2 and #4 that have the issue for me (both in climb and cruise) - the other two cool nicely, even after putting in a Powerflow exhaust and advancing timing at lower power settings via the Surefly mag.  You really need to have the richer carb option on these engines also.  From '68 onward they fixed the cowl flap position on the C, which I suspect didn't help either.  I've "illegally" retarded baseline timing to -23ish on mine but it didn't noticeably help. 

At high CHTs, I think there is a cylinder longevity issue, maybe not in the low 400s though.  My hottest cylinder in climb (#4) actually lasted longer (~1350 hrs) than the other 3 before needing to be reworked - it rarely went any higher than the 430s in climb though, even on the hottest day.  When my blowby-related oil consumption rose to 1qt/3hrs and #4 had a consistently oily bottom plug, I figured it was time and I replaced #4 with factory new, hoping to make it another several hundred hours before overhauling.  After 1.5 years and 200 hours, oil consumption is back down to 1qt/3hrs, the crosshatch looks polished out of #4, and it now also has an oily TOP plug :angry:.   A little while before swapping #4, the Powerflow went in, which made it commonplace to break CHTs of 450 on that cylinder in climb, and I gotta think that's what led to the premature wear.  Now I leave the throttle out 1 inch when going to full power on the runway - this has barely perceptible effect on MP and fuel flow but keeps #2/4 CHTs in early climb below 420 generally. It must be improved mixture distribution that occurs here, though I think they also cool worse from an airflow perspective.   I wish I'd figured this out when #4 was brand new instead of abusing it so badly :(

I'll keep the 1 inch throttle-back in mind if none of the stuff I'm trying to address CHT helps.

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On 10/2/2022 at 12:01 PM, pirate said:

I have the cowl closure on my 70C, I have power flow, I have the dog house properly fitted & sealed, my mags are at 25.

Generally 280-300 ish taxi aggressively leaned 80-90 degree day 

Generally 360-380 ish cruise 

 

 

Thanks for those comparison numbers. Only difference between a 70C & 65C that I'm aware of is fixed cowl flaps versus manually operated

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In a dark hangar, uncowl your mooney but leave the doghouse in place. Stick a flashlight in the doghouse, and anywhere you see light, there’s air escaping. 
 

Seconding the power flow exhaust as a heat source.. that’s not helping your situation.
 

I got after my doghouse aggressively with some sealer and saw significant changes in temperatures. 25 degrees is the number for your timing, but it doesn’t take a lot of adjustment to help. 24.500001 degrees rounds up to 25 in some folks’ book. 
 

I have no idea how you’re measuring temperatures so accurately with a single CHT probe into the Garwin box. It’s telling you 1/4 of the story… and even that is transmitted with some poetic license. 

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With regard to high CHT’s, I throw out the thought that the amount of time exposed to high temperatures might be a factor in how bad it is for one’s cylinders.  I too see high CHT readings in the initial high power climb out phase of flight, however after reaching roughly say 1000AGL I pull the power back a tad, lower the nose a tad to get the speed up, and I see the CHT numbers drop back under 400, 375 or so. The time of “above 400” operation is limited to perhaps 2-3 minutes, and is not in the high temp regime for hours and hours.  I think of it as transient high temp operation. Not that I’m happy about it but I also don’t lose much sleep over it either.

This is on a 1965 M20C with an O360A1A, the €*% doghouse, and the ARI cowl mod.  

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Soooo….

This seems to be more of a how do I cool my M20C better… type discussion…. In that case… I invite @Hank along for the discussion…  :)

 

Dog house health is everything… if you haven’t had this discussion before…

The older Mooneys got the dog house… some are getting an update, non dog house replacement….

Not mentioned in this thread… is updated alternators and starters… that didn’t get updated felt seals… or silicone seals….

Post pics of what you have all around the dog house….

Chances of its health being top notch over several decades is pretty slim….

The air is supposed to flow from top to bottom using air pressure….

When seals on the dog house are ill-fitting… temps go way out of whack… because the airflow stops being pressure driven… the right way…

PP thoughts only, not a mechanic…

Best regards,

-a-

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On 10/12/2022 at 8:17 AM, Pasturepilot said:

In a dark hangar, uncowl your mooney but leave the doghouse in place. Stick a flashlight in the doghouse, and anywhere you see light, there’s air escaping. 

I have no idea how you’re measuring temperatures so accurately with a single CHT probe into the Garwin box. It’s telling you 1/4 of the story… and even that is transmitted with some poetic license. 

I like the flashlight idea to find smaller gaps in the doghouse - thanks. The obvious larger gaps are being sealed.

Just eyeballing the Garwin gauge as best as one can by interpolating using the minimal temp scale provided. 

Turned out the CHT probe when tested was in error by 60 - 70*F

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On 10/14/2022 at 9:00 PM, carusoam said:

Soooo….

This seems to be more of a how do I cool my M20C better… type discussion…. In that case… I invite @Hank along for the discussion…  :)

 

Dog house health is everything… if you haven’t had this discussion before…

The older Mooneys got the dog house… some are getting an update, non dog house replacement….

Not mentioned in this thread… is updated alternators and starters… that didn’t get updated felt seals… or silicone seals….

Post pics of what you have all around the dog house….

Chances of its health being top notch over several decades is pretty slim….

The air is supposed to flow from top to bottom using air pressure….

When seals on the dog house are ill-fitting… temps go way out of whack… because the airflow stops being pressure driven… the right way…

PP thoughts only, not a mechanic…

Best regards,

-a-

Mechanics tested the CHT probe last week & it was in error by 60* to 70*F high at the highest, tested temperature of 360*F. 

Obvious gaps in the doghouse are being sealed. There were quite a few. 

I'm ordering an EI CGR-30P & C monitor. Time to bring this Mooney engine gauges into the 21st century.

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On 10/19/2022 at 3:16 PM, C.J. said:

Mechanics tested the CHT probe last week & it was in error by 60* to 70*F high at the highest, tested temperature of 360*F. 

Obvious gaps in the doghouse are being sealed. There were quite a few. 

I'm ordering an EI CGR-30P & C monitor. Time to bring this Mooney engine gauges into the 21st century.

I installed a CGR30P and C recently as well in my 63C. I am really loving them. With the Lasar cowl mod I have, I see about 415 max on cyl 3 in a VX climb. In cruise I’m in the 330s, it stays very cool, even on hot days. When we installed the engine monitor we went through the doghouse and sealed up any suspect areas with RTV. 

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22 minutes ago, 67 m20F chump said:

I dis the 30p+c as well.  Are you going to replace the fuel senders? I didn’t but I keep thinking it would have been nicer.  The install took some time!8ABAD9D1-7C21-4ED4-8E70-DC1CEA25755B.jpeg.3b3a40c8f0282af4c0e3f996a53a154f.jpeg

I did the magnetic fuel senders. They are pretty accurate, at least while on the ground. 

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I have the ARI cowling mod installed on my M20C, plus powerflow and sureflight. High CHT have been my nightmare for the last years. I tried everything, timing, changed the carb, installed a new doghouse (there was a company in Alaska that made them), went back to magnetos, then back to sureflight and no success. On run up temps went up to 350 and then after take off, they raised to 450. Very frustrating. 

I talked to whoever had an opinion and listened to advice...

Small things helped,  modified my take off technic, played with the throttle, adjusted my timing, turned on carb heat partially, re-sealed doghouse, installed new baffling, changed carburator to increase fuel flow. All these things obviously helped. But what really made a difference were the cowlflaps. I opened them up to the maximun possible and that changed everything. Now my take off temps (with OAT in the 90s) stay below 410 and in cruise I am able to lean and get figures between 380 and 405. 

So look at your cowflaps and check if their aperture is in line with what the Manual says, mine were not. 

 

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On 10/22/2022 at 2:31 PM, phxcobraz said:

I installed a CGR30P and C recently as well in my 63C. I am really loving them. With the Lasar cowl mod I have, I see about 415 max on cyl 3 in a VX climb. In cruise I’m in the 330s, it stays very cool, even on hot days. When we installed the engine monitor we went through the doghouse and sealed up any suspect areas with RTV. 

It will be a few months before the CGR-30P & C will be installed - I just ordered it - 8 weeks lead time plus I have to get on the schedule for installation. At this point it's just great to know that my actual CHT's are significantly lower that what the Garmin gauge indicates.

Glad you're loving the CGR's. Do you have any photos? Did you place them on the right or left panel?

 

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On 10/23/2022 at 2:07 PM, Oscar Avalle said:

I have the ARI cowling mod installed on my M20C, plus powerflow and sureflight. High CHT have been my nightmare for the last years. I tried everything, timing, changed the carb, installed a new doghouse (there was a company in Alaska that made them), went back to magnetos, then back to sureflight and no success. On run up temps went up to 350 and then after take off, they raised to 450. Very frustrating. 

I talked to whoever had an opinion and listened to advice...

Small things helped,  modified my take off technic, played with the throttle, adjusted my timing, turned on carb heat partially, re-sealed doghouse, installed new baffling, changed carburator to increase fuel flow. All these things obviously helped. But what really made a difference were the cowlflaps. I opened them up to the maximun possible and that changed everything. Now my take off temps (with OAT in the 90s) stay below 410 and in cruise I am able to lean and get figures between 380 and 405. 

So look at your cowflaps and check if their aperture is in line with what the Manual says, mine were not. 

 

I hear you on the "nightmare" of high CHT!!!! My CHT probe was tested last week at a "known" temperature of 360*F and gave an indication of 430*F. That 430*F on the Garwin gauge was very tough to look at climbing thru 500 AGL after takeoff. Great to know that at least on my C model I was nowhere near that. I'd initially hoped the LASAR cowl fairing mod would've made a difference, but it didn't. Doghouse gaps & holes were recently sealed off and in maybe 3 months or so I'll have an EI CGR-30 monitor so I'll have a far more accurate CHT reading & on four cylinders instead of just #3. I'll definitely have the cowl flaps checked for aperture. Thanks for that info. 

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On 10/22/2022 at 2:52 PM, 67 m20F chump said:

I dis the 30p+c as well.  Are you going to replace the fuel senders? I didn’t but I keep thinking it would have been nicer.  The install took some time!8ABAD9D1-7C21-4ED4-8E70-DC1CEA25755B.jpeg.3b3a40c8f0282af4c0e3f996a53a154f.jpeg

THANKS for posting this photo. It seems that most monitor photos on MS are JPI installations.

I was planning on putting the CGRs on the right panel but now I'm thinking re-doing the left panel into an "8 Pack".

How many hours did the install take? I'll be changing the fuel senders too with CiES. The guess-ti-mate is at least 40 - 45 hours

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On 10/28/2022 at 11:35 AM, C.J. said:

It will be a few months before the CGR-30P & C will be installed - I just ordered it - 8 weeks lead time plus I have to get on the schedule for installation. At this point it's just great to know that my actual CHT's are significantly lower that what the Garmin gauge indicates.

Glad you're loving the CGR's. Do you have any photos? Did you place them on the right or left panel?

 

Right side of the panel. When I finish doing some other avionics I’ll move them where my transponder and audio panel are. 

AECEF8B4-C8A6-4B9A-9382-BF27FFB1E8EA.jpeg

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