Jetpilot86 Posted April 17 Report Posted April 17 I’ve got an 80dF split between #5 & #6 cylinders. The left flap was jammed on a dent in the cowl and I managed to get it to close more, but not all the way. Any tips on how to adjust it? Quote
Fritz1 Posted April 17 Report Posted April 17 See how much adjustment is still possible on the left cowl flaps pushrod, if nothing left you may have to take the cowl flap out and straighten the area where the bracket for the heim joint is riveted to the cowl flap, soft aluminum straightens easily Quote
LANCECASPER Posted April 17 Report Posted April 17 On 4/16/2024 at 9:12 PM, Jetpilot86 said: I’ve got an 80dF split between #5 & #6 cylinders. The left flap was jammed on a dent in the cowl and I managed to get it to close more, but not all the way. Any tips on how to adjust it? That’s a fiberglass cowl. At this point it probably wouldn’t be a huge deal to repair the fiberglass. But with a “dent” in fiberglass you can be sure it’s got small cracks in it, which will spread. If that comes apart while you’re flying I’m not sure what the results would be, but i can’t imagine it being good. Plus if it goes beyond the point of being able to be repaired try finding a replacement cowl for a Bravo. When you find out how expensive it is to fix the cowl and the cowl flaps properly, including matching paint, etc, you may want to make an insurance claim. Quote
Fritz1 Posted April 18 Report Posted April 18 Ah, did not see the dent in the fiberglass cowl, absolutely repair that first, cowl flap pushrod may still need adjustment, best fiberglass repair is typically done by shops that work on gliders unless you know how to do it yourself from working on model airplanes, motorcycle fairings etc. Quote
Jetpilot86 Posted April 20 Author Report Posted April 20 On 4/17/2024 at 6:38 PM, LANCECASPER said: That’s a fiberglass cowl. At this point it probably wouldn’t be a huge deal to repair the fiberglass. But with a “dent” in fiberglass you can be sure it’s got small cracks in it, which will spread. If that comes apart while you’re flying I’m not sure what the results would be, but i can’t imagine it being good. Plus if it goes beyond the point of being able to be repaired try finding a replacement cowl for a Bravo. When you find out how expensive it is to fix the cowl and the cowl flaps properly, including matching paint, etc, you may want to make an insurance claim. As long as it makes it thru to December, I'll have it dealt with during the repaint then.... I'm more concerned with getting the #6 CHT down, which I can't figure out why it is a problem with the Cowl Flap on that side stuck open for so long.... Quote
LANCECASPER Posted April 20 Report Posted April 20 1 minute ago, Jetpilot86 said: As long as it makes it thru to December, I'll have it dealt with during the repaint then.... I'm more concerned with getting the #6 CHT down, which I can't figure out why it is a problem with the Cowl Flap on that side stuck open for so long.... Let's see a picture of your baffle seals. Quote
carusoam Posted April 20 Report Posted April 20 is that a new dent causing the challenge? or…. Let’s see why one cylinder is reading differently than the five others… often, the odd one out is using a different sensor in a different cylinder location… Check where your ship’s CHT gauge is, and see where the JPI sensor is… To check if it is a sensor challenge, a simple swap of sensors between adjacent cylinders can prove what you are seeing… There is a good chance that somebody installed a ring sensor, to get it to read 50°F too high… bad ring sensors double as spark plug gaskets…. Crummy ring sensors are mounted on the TC well for the regular CHT sensor… PP thoughts only, not a mechanic… Best regards, -a- Quote
Jetpilot86 Posted April 20 Author Report Posted April 20 8 hours ago, carusoam said: is that a new dent causing the challenge? or…. Let’s see why one cylinder is reading differently than the five others… often, the odd one out is using a different sensor in a different cylinder location… Check where your ship’s CHT gauge is, and see where the JPI sensor is… To check if it is a sensor challenge, a simple swap of sensors between adjacent cylinders can prove what you are seeing… There is a good chance that somebody installed a ring sensor, to get it to read 50°F too high… bad ring sensors double as spark plug gaskets…. Crummy ring sensors are mounted on the TC well for the regular CHT sensor… PP thoughts only, not a mechanic… Best regards, -a- The dent probably predates my ownership, but I’ll check the rest out. Thanks! Quote
Jetpilot86 Posted April 20 Author Report Posted April 20 8 hours ago, LANCECASPER said: Let's see a picture of your baffle seals. They are a new GeeBee install by Maxwell. Found one bulge and cut it so it overlaps. They are good, now. 1 Quote
LANCECASPER Posted April 20 Report Posted April 20 4 hours ago, Jetpilot86 said: The dent probably predates my ownership, but I’ll check the rest out. Thanks! It's possible when they picked up the airplane that they jammed the cowl flaps or dented the cowl. http://www.kathrynsreport.com/2021/09/mooney-m20m-257-tls-n64sm-incident.html When it was for sale it 2023 it only shows the cowl flaps open, so the pre-buy might have missed that: https://www.aircraft.com/aircraft/228063917/n64sm-1995-mooney-m20m-tls @carusoam's suggestion to swap cht probes with another cylinder is a good idea. If that doesn't solve it, since your engine is a factory OH Lycoming with low hours, I would get Lycoming involved. 2 Quote
Jetpilot86 Posted April 20 Author Report Posted April 20 4 hours ago, LANCECASPER said: It's possible when they picked up the airplane that they jammed the cowl flaps or dented the cowl. http://www.kathrynsreport.com/2021/09/mooney-m20m-257-tls-n64sm-incident.html When it was for sale it 2023 it only shows the cowl flaps open, so the pre-buy might have missed that: https://www.aircraft.com/aircraft/228063917/n64sm-1995-mooney-m20m-tls @carusoam's suggestion to swap cht probes with another cylinder is a good idea. If that doesn't solve it, since your engine is a factory OH Lycoming with low hours, I would get Lycoming involved. Ya, I’ve got all those pics and more. Nothing I can discern from those pics. Quote
carusoam Posted April 20 Report Posted April 20 There are a few good things baked into this approach… 1) Maxwell is a top of the line shop… hard to find anything better. 2) BeeGee has a great record for making fantastic cowling seals. 3) To get one cylinder to be 50°F off from the others… something should stand out… - additional gap somewhere - lack of clearance elsewhere - something that robs the airflow from one cylinder, and allows it to flow past another instead…. 4) Keep in mind… airflow at the top is affected by the air flow at the bottom… make sure all of the air passages go all the way in, and are free to go all the way back out…. 5) Don’t trust the instruments, until proven to be correct…. PP thoughts only, not a mechanic… Best regards, -a- 1 Quote
Jetpilot86 Posted April 20 Author Report Posted April 20 Pre baffle swap. Head scratcher is the engine has 50 hours on it. Quote
LANCECASPER Posted April 20 Report Posted April 20 1 hour ago, Jetpilot86 said: Pre baffle swap. Head scratcher is the engine has 50 hours on it. If that is a factory overhaul you have a two year warranty on the cylinders. (https://www.lycoming.com/services/overhaul-engines) If you've already swapped the CHT and determined that the cylinder is really running that much hotter than the rest I would talk to Lycoming asap. 1 Quote
carusoam Posted April 21 Report Posted April 21 Also… CHT = ENERGY IN - ENERGY OUT There are two parts to this equation. We have been discussing cooling issues pretty extensively… Did we look at any oddities related to the EGTs? is the odd ball cylinder’s EGT peaking any sooner than the others? Can you perform a Gami spread test, to see if anything stands out regarding fuel flow to the odd cylinder? Back to the warranty issue… the Bravo’s cylinders are oil cooled heads. How do mechanics check that the oil cooling is working properly on all of the cylinders? PP thoughts on,y, not a mechanic or Lycoming owner… Best regards, -a- Quote
Fritz1 Posted April 21 Report Posted April 21 If CHT probes swapped with no change, blowing the oil lines to the exhaust valve guides through can't hurt, maybe piece of debris in no 6 line or valve guide channel, do spread test and talk to gami, maybe fuel flow no 6, no result talk to Lycoming asap Quote
Jetpilot86 Posted April 21 Author Report Posted April 21 9 hours ago, carusoam said: Also… CHT = ENERGY IN - ENERGY OUT There are two parts to this equation. We have been discussing cooling issues pretty extensively… Did we look at any oddities related to the EGTs? is the odd ball cylinder’s EGT peaking any sooner than the others? Can you perform a Gami spread test, to see if anything stands out regarding fuel flow to the odd cylinder? Back to the warranty issue… the Bravo’s cylinders are oil cooled heads. How do mechanics check that the oil cooling is working properly on all of the cylinders? PP thoughts on,y, not a mechanic or Lycoming owner… Best regards, -a- Other than #5 & #6 being the last to peak, nothing odd with EGT’s. The GAMI sweep, pre-FineWires was right at .5gal, but keep the troubleshooting ideas coming. The oil cooling blockage is an interesting idea, the oil has about 20 hours on it, averages 185-190 in cruise, and looks clean. I’m due for a change by 25 hours on the oil. 1 Quote
Jetpilot86 Posted May 13 Author Report Posted May 13 Changed the oil from Shell to the Phillips X/C + Camguard last week. Found another small bulge in the new baffling on the left sidewall of the cowl and trimmed it to lay flat. Flew it a few days ago and after noticing something from the previous flight and decided to accelerate to 130kias minimum before setting Key 58 climb power. As a result, initial climb CHT's dropped from 400-415dF, to 380 and less, with the Cowl Flaps at 1/2, on the #6 Cylinder. Was able to run 50LoP at Key 52 and #6 CHT fell into the middle of the pack vs being the highest. Even at Power FF & Key 52, I was able to keep the #6 CHT under 380 with a bit of Cowl Flap. TIT was under 1550dF. This was at 11500' and ISA +6. Very pleased at how smooth she was running LoP with the factory injectors. Not sure if after 50 hours SFOH she finally broke in all the way, that last little bulge was the problem, if it was the change in oil since P X/C supposedly runs cooler, or I was just operating her better, but very pleased with the latest flight. Did some more comparisons vs the POH and am making the book numbers, probably the fresh wax job. Now that the sales tax window in FL has passed, looking forward to my first flight down there for Memorial Day. Quote
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