Dood Posted May 13, 2018 Report Share Posted May 13, 2018 Good evening, i need one more time community’s help for my M20J It’s hard to keep my #1 cylinder upper 300° without the #3 reaches 380° I think the #1 is too rich; You can see the flight data here Can you tell me what is the average CHT, cylinder by cylinder on your plane ? To compare and to submit your anwers to my mechanical thanks, Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 13, 2018 Report Share Posted May 13, 2018 Dood, There is a lot of JPI data posted by people flying around with io360s.... They probably show actual CHTs varying 15 -30°F from each other? (Where the comparison is more important than the actual temp.) Your collection of data, online is really easy to review... (nice way to share your data) When one CHT gets out of line like yours... 1) First need to review, what thermocouple is supplying the odd piece of data...? There doesn’t seem to be one really bad one... they all seam to be varying from each other.... 2) Does the EGT support there is something happening in that cylinder....? 3) Are you running LOP? Or ROP? Do you have FF to go with that? 4) If you are running LOP, cylinder one is propbably going leaner sooner than the others... 5) If you are running ROP, cylinder one is staying richer than the others... 6) you might consider doing things like the Gami lean test to see what the EGT spread looks like... this gives you a feeling of how much more fuel is going to each cylinder... the spread is Best when closer to zero... all EGTs peak at the same time... 7) If you have a large gami spread, there is a test, often called the baby food jar test... it tests the flow rate of each fuel injector into a separate jar... 8) it looks like you may have a pretty wide gami spread... there are solutions for that once they are found.... 9) Are you familiar with the Gami spread test? The Savvy site has a good description of it... 10) The folks at Savvy can be paid to review your data and make recommendations... that may make a good next step too.... Lets see how far we can get in conversation prior to spending a lot of euros. There is going to be euros spent, just better targeted the next time.... It looks like CHT #1 is really running cooler than everything else... EGT and CHT... I’m guessing that you are flying LOP, the more you lean, the colder CHT1 gets... lean more and CHT1 will quit operating before the rest... If running ROP, the opposite should happen, CHT and CHT1 will peak first and go LOP sooner than the others... If this is all true... you really want to get into the cleaning fuel injectors and see if anything comes from that... If they are all clean.... the baby food jars are next... Trying to get the gami spread as close to zero as possible.... gami balanced injectors are worth reading up on at this time... Once the gami spread is close to zero... looking to balance the air cooling through the cowling becomes a driving factor... check all baffling and silicone seals... any gaps or wavy rubber can be bad for airflow... post some pics of the seals and their condition... We have a seal supplier that may be of interest to you... Again, nice collection of data, that was easy to review... How is that for a bunch of PP ideas... not mechanic ideas... that’s a lot of info... let me know if I missed something... Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
Bob - S50 Posted May 13, 2018 Report Share Posted May 13, 2018 (edited) I only looked at your last flight. I do not think #1 is too rich. All your cylinders peaked at almost the exact same time (very low GAMI spread) which is good. Both 3 & 4 are hotter than 1 & 2 which makes sense because they are at the back of your engine. It also looked like you found peak and then went quite a bit ROP. Depending on how ROP you went (in terms of degrees) that may actually heat up your engine. Here are a couple things to consider: 1. If it was only #3 that was too hot you could rig the right cowl flap open just a bit. You are allowed to rig the cowl flaps so that they are open just a little bit when the control is fully forward. We do that on the right side to keep our #3 cooler. However, just doing the right side won't help #4. You might choose to do both sides but I'm not sure what that will do to 1 & 2 CHT's. Probably make them even cooler. Don't know for sure though. 2. While I hesitate to bring up LOP vs ROP, you don't have to go very far LOP to get a significant drop in CHT. On the other hand, a little ROP makes it worse and a lot ROP helps but not as much as the same amount LOP. You might consider trying LOP next time. Find peak and then go about 30 LOP and let it stabilize to see what you get. During the summer at higher altitudes, our #3 flirts with 400. When it does, I go just a little further LOP (maybe 10 degrees) and it usually brings the CHT down to about 390. 3. It looks like you run at 2400 RPM. If you use 2500 or 2600 RPM, I think you'll find that also helps bring down the CHT because peak pressure will occur further after TDC. Edited May 14, 2018 by Bob - S50 1 Quote Link to comment Share on other sites More sharing options...
mooneyflyfast Posted May 14, 2018 Report Share Posted May 14, 2018 Is the baffle in place in front of your no. 1 cylinder? My no. 1 was my hottest cylinder until I trimmed the baffle 3/4 inch. It is now the coolest cylinder. I believe the baffle is there to prevent no. 1 running too cool. A missing or shortened no. 1 baffle could explain what you are seeing. I wouldn't be concerned about the temperatures you are seeing. 380 is good and I don't see a downside to a 300 CHT. Quote Link to comment Share on other sites More sharing options...
bradp Posted May 14, 2018 Report Share Posted May 14, 2018 What type of CHT probe do you have for #3? Washer or bayonet? Add 25-40F error for use of a washer probe. Also put a piece of 1/8” silicone baffle seal (1”x1/2”) between the aluminum baffle and the fins of #3. Send us a picture of your baffle seals for comments. If they don’t seal properly you can have mucho CHT issues. One quick way is to shine a bright flashlight in the oil door and look from the front. Anywhere you see light you are losing cooling 1 Quote Link to comment Share on other sites More sharing options...
jaylw314 Posted May 14, 2018 Report Share Posted May 14, 2018 Look at your flight 2/23/18. When you leaned at 00:34:30, your GAMI spread was only 0.3. Your cylinder fuel mixtures are pretty damn good. If you have the factory CHT probe in cylinder #3 (like I think most IO-360's are), you have either a spark plug gasket or piggyback thermocouple for the engine monitor. These can be off by 20-50 degF Make sure your engine baffling is solid. FWIW, my cylinders generally run: #1: 0 #2: -20 degF #3: -40 degF #4: 0 so it's pretty different from yours Quote Link to comment Share on other sites More sharing options...
KSMooniac Posted May 14, 2018 Report Share Posted May 14, 2018 I've got all of mine within 8-10 degrees now.Sent from my LG-US996 using Tapatalk Quote Link to comment Share on other sites More sharing options...
Bartman Posted May 14, 2018 Report Share Posted May 14, 2018 New baffle seals fixed my variations, and I run cooler across the board at the same power settings and conditions. I used to see 380 in climb with high OAT on I think #3 occasionally, but have not in 3 years now. Quote Link to comment Share on other sites More sharing options...
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